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Kessler M, Aros-Mualin D. The power of independent generations in plants. THE NEW PHYTOLOGIST 2024. [PMID: 39329429 DOI: 10.1111/nph.20162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/28/2024]
Affiliation(s)
- Michael Kessler
- Systematic and Evolutionary Botany, University of Zurich, Zurich, Switzerland
| | - Daniela Aros-Mualin
- Department of Botany and Plant Pathology, Purdue Center for Plant Biology, Purdue University, West Lafayette, IN, 47907, USA
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2
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Yoneoka K, Fujiwara T, Kataoka T, Hori K, Ebihara A, Murakami N. Morphological and functional evolution of gametophytes in epilithic Hymenasplenium murakami-hatanakae (Aspleniaceae): The fifth family capable of producing the independent gametophytes. JOURNAL OF PLANT RESEARCH 2024; 137:815-828. [PMID: 38918283 PMCID: PMC11393290 DOI: 10.1007/s10265-024-01553-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Accepted: 06/02/2024] [Indexed: 06/27/2024]
Abstract
The fern independent gametophytes that can maintain populations by vegetative reproduction without conspecific sporophytes have been considered an unusual phenomenon found in some epiphytic or epilithic species of Hymenophyllaceae, Pteridaceae, Lomariopsidaceae, and Polypodiaceae. By chance, the discovery of mysterious strap-like gametophytes on Izu-Oshima Island, Japan, has led to the hypothesis that Hymenasplenium murakami-hatanakae, a fern species belonging to Aspleniaceae, can also form independent gametophytes. Our investigation revealed gametophyte populations of H. murakami-hatanakae on three islands in the Izu Islands. Based on chloroplast DNA analysis of the gametophyte and sporophyte populations, the gametophytes were found to be maintained by vegetative reproduction without a new supply of spores from sporophytes. A comparison of the surrounding vegetation at the collection sites showed that environmental factors such as light and humidity may influence the maintenance of gametophyte populations. These results clearly show that H. murakami-hatanakae is one of the ferns capable of forming independent gametophytes. This is the first report of independent gametophytes from the suborder Aspleniineae (eupolypod II). The discovery of the independent gametophyte within a phylogenetic lineage previously thought not to form independent gametophytes will provide important insights into the morphological and functional evolution of gametophytes in ferns.
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Affiliation(s)
- Katsuhiro Yoneoka
- Makino Herbarium, Tokyo Metropolitan University, 1-1 Minami-Osawa 1-1, Hachioji, Tokyo, 192-0397, Japan.
| | - Tao Fujiwara
- The Mt. Fuji Institute for Nature and Biology, Showa University, 4562 Kamiyoshida, Fujiyoshida, Yamanashi, 403-0005, Japan
| | - Toshifumi Kataoka
- Makino Herbarium, Tokyo Metropolitan University, 1-1 Minami-Osawa 1-1, Hachioji, Tokyo, 192-0397, Japan
| | - Kiyotaka Hori
- Makino Botanical Garden, 4200-6 Godaisan, Kouchi-City, Kouchi, 780-0870, Japan
| | - Atsushi Ebihara
- Department of Botany, National Museum of Nature and Science, 4-1-1 Amakubo, Tsukuba, Ibaraki, 305-0005, Japan
| | - Noriaki Murakami
- Makino Herbarium, Tokyo Metropolitan University, 1-1 Minami-Osawa 1-1, Hachioji, Tokyo, 192-0397, Japan
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3
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Blake-Mahmud J, Sessa EB, Visger CJ, Watkins JE. Polyploidy and environmental stress response: a comparative study of fern gametophytes. THE NEW PHYTOLOGIST 2024. [PMID: 39044655 DOI: 10.1111/nph.19969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Accepted: 06/24/2024] [Indexed: 07/25/2024]
Abstract
Climate change is rapidly altering natural habitats and generating complex patterns of environmental stress. Ferns are major components of many forest understories and, given their independent gametophyte generation, may experience unique pressures in emerging temperature and drought regimes. Polyploidy is widespread in ferns and may provide a selective advantage in these rapidly changing environments. This work aimed to understand whether the gametophytes of allopolyploid ferns respond differently to climate-related physiological stress than their diploid parents. The experimental approach involved a multifactorial design with 27 treatment combinations including exposure to multiple levels of drought and temperature over three treatment durations, with recovery measured at multiple timepoints. We measured Chl fluorescence from over 2000 gametophytes to evaluate stress avoidance and tolerance in diploid and polyploid species. Polyploids generally showed a greater ability to avoid and/or tolerate a range of stress conditions compared with their diploid counterparts, suggesting that polyploidy may confer enhanced flexibility and resilience under climate stress. Overall, these results suggest that polyploidy may provide some resilience to climate change in mixed ploidy populations. However, all species remain susceptible to the impacts of extreme drought and heat stress.
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Affiliation(s)
| | - Emily B Sessa
- William & Lynda Steere Herbarium, New York Botanical Garden, Bronx, NY, 10458, USA
| | - Clayton J Visger
- Department of Biological Sciences, California State University, Sacramento, CA, 95819, USA
| | - James E Watkins
- Department of Biology, Colgate University, 13 Oak Drive, Hamilton, NY, 13346, USA
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Wefferling KM, Castro M, Castro S, Holmlund H, Loureiro J, Rothfels CJ, Schuettpelz E. Polyploid goldback and silverback ferns (Pentagramma) occupy a wider, colder, and wetter bioclimatic niche than diploid counterparts. AMERICAN JOURNAL OF BOTANY 2024; 111:e16305. [PMID: 38517199 DOI: 10.1002/ajb2.16305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 01/22/2024] [Accepted: 01/22/2024] [Indexed: 03/23/2024]
Abstract
PREMISE The western North American fern genus Pentagramma (Pteridaceae) is characterized by complex patterns of ploidy variation, an understanding of which is critical to comprehending both the evolutionary processes within the genus and its current diversity. METHODS We undertook a cytogeographic study across the range of the genus, using a combination of chromosome counts and flow cytometry to infer ploidy level. Bioclimatic variables and elevation were used to compare niches. RESULTS We found that diploids and tetraploids are common and widespread, and triploids are rare and sporadic; in contrast with genome size inferences in earlier studies, no hexaploids were found. Diploids and tetraploids show different geographic ranges: only tetraploids were found in the northernmost portion of the range (Washington, Oregon, and British Columbia) and only diploids were found in the Sierra Nevada of California. Diploid, triploid, and tetraploid cytotypes were found to co-occur in relatively few localities: in the southern (San Diego County, California) and desert Southwest (Arizona) parts of the range, and along the Pacific Coast of California. CONCLUSIONS Tetraploids occupy a wider bioclimatic niche than diploids both within P. triangularis and at the genus-wide scale. It is unknown whether the wider niche of tetraploids is due to their expansion upon the diploid niche, if diploids have contracted their niche due to competition or changing abiotic conditions, or if this wider niche occupancy is due to multiple origins of tetraploids.
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Affiliation(s)
- Keir M Wefferling
- Department of Biology, Gary A. Fewless Herbarium, Cofrin Center for Biodiversity, University of Wisconsin-Green Bay, Green Bay, 54311, Wisconsin, USA
| | - Mariana Castro
- Department of Life Sciences, Centre for Functional Ecology, University of Coimbra, Coimbra, Portugal
| | - Sílvia Castro
- Department of Life Sciences, Centre for Functional Ecology, University of Coimbra, Coimbra, Portugal
| | - Helen Holmlund
- Natural Science Division, Pepperdine University, Malibu, 90263, California, USA
| | - João Loureiro
- Department of Life Sciences, Centre for Functional Ecology, University of Coimbra, Coimbra, Portugal
| | - Carl J Rothfels
- Department of Biology, Ecology Center, and Intermountain Herbarium, Utah State University, Logan, 84322, Utah, USA
| | - Eric Schuettpelz
- Department of Botany, National Museum of Natural History, Smithsonian Institution, Washington, 20560, DC, USA
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Chen XZ, Hogan JA, Wang CP, Wang PL, Lin TC. Responses of a common tropical epiphyte, Asplenium nidus, to changes in water and nutrient availability. AOB PLANTS 2023; 15:plad076. [PMID: 38046406 PMCID: PMC10689150 DOI: 10.1093/aobpla/plad076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Accepted: 11/08/2023] [Indexed: 12/05/2023]
Abstract
Epiphytes are highly dependent on atmospheric inputs of water and nutrients. Reductions in water availability associated with warming and climate change and continual atmospheric nitrogen (N) deposition can affect plant growth but few studies have evaluated the effects of changes in both water and nutrient availabilities on epiphytes. We experimentally tested whether epiphyte growth is more water- or nutrient-limited, if nutrient limitation was stronger for nitrogen or phosphorus, and whether nutrient limitation interacts with water availability. We applied watering (high and low) and nutrient addition (control, +N, +P, +N+P) treatments to greenhouse-grown Asplenium nidus, a common epiphytic fern found in many tropical and subtropical wet forests. We measured leaf area production and leaf elemental concentrations to assess how A. nidus growth and physiology respond to changes in water and nutrient availabilities. We found that leaf growth of A. nidus was more affected by water availability than nutrient addition and the effect of adding nutrients was not fully realized under low-water availability. Among the different nutrient treatments, +N+P had the greatest effects on A. nidus growth and physiology in both watering treatments. Watering treatment changed leaf elemental concentrations but not their ratios (i.e. C:N and N:P). Nutrient addition altered C:N and N:P ratios and increased the concentration of the added elements in leaves, with more pronounced increases in the high-watering treatment. We conclude that the growth of A. nidus is more water- than nutrient-limited. When nutrient limitation occurs (i.e. under high-water availability), nutrient co-limitation is stronger than limitation by N or P alone. This result taken together with studies of other epiphytes suggests greater water than nutrient limitation is likely widespread among epiphytic plants. The limited effects of nutrient addition in the low-water treatment suggest that the effect of atmospheric N deposition on epiphyte growth will be limited when water availability is low.
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Affiliation(s)
- Xiao-Zhen Chen
- Department of Life Science, National Taiwan Normal University, Taipei 11677, Taiwan
| | - J Aaron Hogan
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - Chiao-Ping Wang
- Silviculture Division, Taiwan Forestry Research Institute, Taipei 10066, Taiwan
| | - Pei-Ling Wang
- Institute of Oceanography, National Taiwan University, Taipei 10617, Taiwan
| | - Teng-Chiu Lin
- Department of Life Science, National Taiwan Normal University, Taipei 11677, Taiwan
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Pittermann J, Baer A, Campany C, Jansen S, Holmlund H, Schuettpelz E, Mehltreter K, Watkins JE. A reduced role for water transport during the Cenozoic evolution of epiphytic Eupolypod ferns. THE NEW PHYTOLOGIST 2023; 237:1745-1758. [PMID: 36484140 DOI: 10.1111/nph.18667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 11/15/2022] [Indexed: 06/17/2023]
Abstract
The Cretaceous-Cenozoic expansion of tropical forests created canopy space that was subsequently occupied by diverse epiphytic communities including Eupolypod ferns. Eupolypods proliferated in this more stressful niche, where lower competition enabled the adaptive radiation of thousands of species. Here, we examine whether xylem traits helped shape the Cenozoic radiation of Eupolypod ferns. We characterized the petiole xylem anatomy of 39 species belonging to the Eupolypod I and Eupolypod II clades occupying the epiphytic, hemiepiphytic, and terrestrial niche, and we assessed vulnerability to embolism in a subset of species. The transition to the canopy was associated with reduced xylem content and smaller tracheid diameters, but no differences were found in species vulnerability to embolism and pit membrane thickness. Phylogenetic analyses support selection for traits associated with reduced water transport in Eupolypod 1 species. We posit that in Eupolypod epiphytes, selection favored water retention via thicker leaves and lower stomatal density over higher rates of water transport. Consequently, lower leaf water loss was coupled with smaller quantities of xylem and narrower tracheid diameters. Traits associated with water conservation were evident in terrestrial Eupolypod 1 ferns and may have predisposed this clade toward radiation in the canopy.
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Affiliation(s)
- Jarmila Pittermann
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, 95060, USA
| | - Alex Baer
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, 95060, USA
| | - Courtney Campany
- Department of Biology, Shepherd University, Shepherdstown, WV, 25443, USA
| | - Steven Jansen
- Institute for Systematic Botany and Ecology, University of Ulm, Ulm, 89081, Germany
| | - Helen Holmlund
- Natural Science Division, Pepperdine University, Malibu, CA, 90263, USA
| | - Eric Schuettpelz
- Department of Botany, National Museum of Natural History, Smithsonian Institution, Washington, DC, 20560, USA
| | - Klaus Mehltreter
- Red de Ecologia Funcíonal, Instituto de Ecología A.C, Xalapa, Veracruz, 91073, Mexico
| | - James E Watkins
- Department of Biology, Colgate University, Hamilton, NY, 13346, USA
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7
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Pietrak A, Salachna P, Łopusiewicz Ł. Changes in Growth, Ionic Status, Metabolites Content and Antioxidant Activity of Two Ferns Exposed to Shade, Full Sunlight, and Salinity. Int J Mol Sci 2022; 24:ijms24010296. [PMID: 36613740 PMCID: PMC9820618 DOI: 10.3390/ijms24010296] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 12/08/2022] [Accepted: 12/20/2022] [Indexed: 12/28/2022] Open
Abstract
The interactions between ferns and the environment have been frequently researched. However, detailed data on how ferns respond to specific stresses and a combination of stress factors during cultivation are lacking. This study assessed the effects of salinity and full sunlight and the combination of both stresses on the growth and selected metabolic parameters of two hardy ferns (Athyrium nipponicum cv. Red Beauty and Dryopteris erythrosora) under production conditions. Hardy ferns are highly interesting ornamental plants that can serve as a potential source of antioxidants for the pharmaceutical, cosmetic, and food industries. The results showed that in both ferns, salinity and salinity combined with full sunlight lowered the dry weight of the aerial part and potassium/sodium and calcium/potassium ratio compared with control plants. Salinity, full sunlight, and multi-stress did not affect the total polyphenol content in both ferns but increased the total free amino acids and flavonoids in D. erythrosora. In A. nipponicum cv. Red Beauty, all stressors decreased the total free amino acids content and the antioxidant activities determined by ABTS, DPPH, FRAP, and reducing power assays. By contrast, plants of D. erythrosora grown under full sunlight are characterized by higher antioxidant activities determined by DPPH, FRAP, and reducing power assays. Overall, a greater adaptive potential to abiotic stresses was found in D. erythrosora than in A. nipponicum cv. Red Beauty. Our findings shed some light on the physiological mechanisms responsible for sensitivity/tolerance to salinity, full sunlight, and combined stresses in hardy ferns.
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Affiliation(s)
- Anna Pietrak
- Department of Horticulture, West Pomeranian University of Technology in Szczecin, 71-459 Szczecin, Poland
- Correspondence: (A.P.); (P.S.); Tel.: +48-91-449-6359 (P.S.)
| | - Piotr Salachna
- Department of Horticulture, West Pomeranian University of Technology in Szczecin, 71-459 Szczecin, Poland
- Correspondence: (A.P.); (P.S.); Tel.: +48-91-449-6359 (P.S.)
| | - Łukasz Łopusiewicz
- Center of Bioimmobilisation and Innovative Packaging Materials, West Pomeranian University of Technology in Szczecin, 71-270 Szczecin, Poland
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Bouda M, Huggett BA, Prats KA, Wason JW, Wilson JP, Brodersen CR. Hydraulic failure as a primary driver of xylem network evolution in early vascular plants. Science 2022; 378:642-646. [DOI: 10.1126/science.add2910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The earliest vascular plants had stems with a central cylindrical strand of water-conducting xylem, which rapidly diversified into more complex shapes. This diversification is understood to coincide with increases in plant body size and branching; however, no selection pressure favoring xylem strand-shape complexity is known. We show that incremental changes in xylem network organization that diverge from the cylindrical ancestral form lead to progressively greater drought resistance by reducing the risk of hydraulic failure. As xylem strand complexity increases, independent pathways for embolism spread become fewer and increasingly concentrated in more centrally located conduits, thus limiting the systemic spread of embolism during drought. Selection by drought may thus explain observed trajectories of xylem strand evolution in the fossil record and the diversity of extant forms.
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Affiliation(s)
- Martin Bouda
- Institute of Botany, Czech Academy of Sciences, Průhonice, Czechia
| | | | - Kyra A. Prats
- Yale School of the Environment, New Haven, CT, USA
- New York Botanical Garden, Bronx, NY, USA
| | - Jay W. Wason
- School of Forest Resources, University of Maine, Orono, ME, USA
| | - Jonathan P. Wilson
- Department of Environmental Studies, Haverford College, Haverford, PA, USA
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Krieg CP, Chambers SM. The ecology and physiology of fern gametophytes: A methodological synthesis. APPLICATIONS IN PLANT SCIENCES 2022; 10:e11464. [PMID: 35495196 PMCID: PMC9039797 DOI: 10.1002/aps3.11464] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 12/21/2021] [Accepted: 01/10/2022] [Indexed: 05/14/2023]
Abstract
All green plants alternate between the gametophyte and sporophyte life stages, but only seed-free vascular plants (ferns and lycophytes) have independent, free-living gametophytes. Fern and lycophyte gametophytes are significantly reduced in size and morphological complexity relative to their sporophytic counterparts and have often been overlooked in ecological and physiological studies. Understanding the ecological and physiological factors that directly impact this life stage is of critical importance because the ultimate existence of a sporophyte is dependent upon successful fertilization in the gametophyte generation. Furthermore, previous research has shown that the dual nature of the life cycle and the high dispersibility of spores can result in different geographic patterns between gametophytes and their respective sporophytes. This variation in distribution patterns likely exacerbates the separation of selective pressures acting on gametophyte and sporophyte generations, and can uniquely impact a species' ecology and physiology. Here, we provide a review of historical and contemporary methodologies used to examine ecological and physiological aspects of fern gametophytes, as well as those that allow for comparisons between the two generations. We conclude by suggesting methodological approaches to answer currently outstanding questions. We hope that the information covered herein will serve as a guide to current researchers and stimulate future discoveries in fern gametophyte ecology and physiology.
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Affiliation(s)
| | - Sally M. Chambers
- Department of BotanyMarie Selby Botanical GardensSarasotaFlorida34236USA
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10
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Prats KA, Brodersen CR. Desiccation and rehydration dynamics in the epiphytic resurrection fern Pleopeltis polypodioides. PLANT PHYSIOLOGY 2021; 187:1501-1518. [PMID: 34618062 PMCID: PMC8566288 DOI: 10.1093/plphys/kiab361] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 07/01/2021] [Indexed: 05/13/2023]
Abstract
The epiphytic resurrection-or desiccation-tolerant (DT)-fern Pleopeltis polypodioides can survive extreme desiccation and recover physiological activity within hours of rehydration. Yet, how epiphytic DT ferns coordinate between deterioration and recovery of their hydraulic and photosynthetic systems remains poorly understood. We examined the functional status of the leaf vascular system, chlorophyll fluorescence, and photosynthetic rate during desiccation and rehydration of P. polypodioides. Xylem tracheids in the stipe embolized within 3-4 h during dehydration. When the leaf and rhizome received water, tracheids refilled after ∼24 h, which occurred along with dramatic structural changes in the stele. Photosynthetic rate and chlorophyll fluorescence recovered to predesiccation values within 12 h of rehydration, regardless of whether fronds were connected to their rhizome. Our data show that the epiphytic DT fern P. polypodioides can utilize foliar water uptake to rehydrate the leaf mesophyll and recover photosynthesis despite a broken hydraulic connection to the rhizome.
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Affiliation(s)
- Kyra A Prats
- School of the Environment, Yale University, New Haven, Connecticut, USA
- Author for communication:
| | - Craig R Brodersen
- School of the Environment, Yale University, New Haven, Connecticut, USA
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11
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Reproductive Stage Drought Tolerance in Wheat: Importance of Stomatal Conductance and Plant Growth Regulators. Genes (Basel) 2021; 12:genes12111742. [PMID: 34828346 PMCID: PMC8623834 DOI: 10.3390/genes12111742] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 10/28/2021] [Accepted: 10/28/2021] [Indexed: 12/13/2022] Open
Abstract
Drought stress requires plants to adjust their water balance to maintain tissue water levels. Isohydric plants (‘water-savers’) typically achieve this through stomatal closure, while anisohydric plants (‘water-wasters’) use osmotic adjustment and maintain stomatal conductance. Isohydry or anisohydry allows plant species to adapt to different environments. In this paper we show that both mechanisms occur in bread wheat (Triticum aestivum L.). Wheat lines with reproductive drought-tolerance delay stomatal closure and are temporarily anisohydric, before closing stomata and become isohydric at higher threshold levels of drought stress. Drought-sensitive wheat is isohydric from the start of the drought treatment. The capacity of the drought-tolerant line to maintain stomatal conductance correlates with repression of ABA synthesis in spikes and flag leaves. Gene expression profiling revealed major differences in the drought response in spikes and flag leaves of both wheat lines. While the isohydric drought-sensitive line enters a passive growth mode (arrest of photosynthesis, protein translation), the tolerant line mounts a stronger stress defence response (ROS protection, LEA proteins, cuticle synthesis). The drought response of the tolerant line is characterised by a strong response in the spike, displaying enrichment of genes involved in auxin, cytokinin and ethylene metabolism/signalling. While isohydry may offer advantages for longer term drought stress, anisohydry may be more beneficial when drought stress occurs during the critical stages of wheat spike development, ultimately improving grain yield.
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12
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Nitta JH, Watkins JE, Holbrook NM, Wang TW, Davis CC. Ecophysiological differentiation between life stages in filmy ferns (Hymenophyllaceae). JOURNAL OF PLANT RESEARCH 2021; 134:971-988. [PMID: 34117960 DOI: 10.1007/s10265-021-01318-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 06/03/2021] [Indexed: 06/12/2023]
Abstract
Desiccation tolerance was a key trait that allowed plants to colonize land. However, little is known about the transition from desiccation tolerant non-vascular plants to desiccation sensitive vascular ones. Filmy ferns (Hymenophyllaceae) represent a useful system to investigate how water-stress strategies differ between non-vascular and vascular stages within a single organism because they have vascularized sporophytes and nonvascular gametophytes that are each capable of varying degrees of desiccation tolerance. To explore this, we surveyed sporophytes and gametophytes of 19 species (22 taxa including varieties) of filmy ferns on Moorea (French Polynesia) and used chlorophyll fluorescence to measure desiccation tolerance and light responses. We conducted phylogenetically informed analyses to identify differences in physiology between life stages and growth habits. Gametophytes had similar or less desiccation tolerance (ability to recover from 2 days desiccation at - 86 MPa) and lower photosynthetic optima (maximum electron transport rate of photosystem II and light level at 95% of that rate) than sporophytes. Epiphytes were more tolerant of desiccation than terrestrial species in both life stages. Despite their lack of greater physiological tolerances, gametophytes of several species occurred over a wider elevational range than conspecific sporophytes. Our results demonstrate that filmy fern gametophytes and sporophytes differ in their physiology and niche requirements, and point to the importance of microhabitat in shaping the evolution of water-use strategies in vascular plants.
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Affiliation(s)
- Joel H Nitta
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA.
- Harvard University Herbaria, 22 Divinity Avenue, Cambridge, MA, 02138, USA.
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, 113-0032, Japan.
| | - James E Watkins
- Department of Biology, Colgate University, 13 Oak Drive, Hamilton, NY, 13346, USA
| | - N Michele Holbrook
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Tristan W Wang
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
- Harvard University Herbaria, 22 Divinity Avenue, Cambridge, MA, 02138, USA
- Section of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Charles C Davis
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
- Harvard University Herbaria, 22 Divinity Avenue, Cambridge, MA, 02138, USA
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Pittermann J, Baer A, Sang Y. Primary tissues may affect estimates of cavitation resistance in ferns. THE NEW PHYTOLOGIST 2021; 231:285-296. [PMID: 33786827 DOI: 10.1111/nph.17374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 03/11/2021] [Indexed: 06/12/2023]
Abstract
Different methods of measuring cavitation resistance in fern petioles lead to variable results, particularly with respect to the P50 metric. We hypothesised that the fern dictyostele structure affects air entry into the xylem, and therefore impacts the shape of the vulnerability curve. Our study examined this variation by comparing vulnerability curves constructed on petioles collected from evergreen and deciduous ferns in the field, with curves generated using the standard centrifuge, air-injection and bench-top dehydration methods. Additional experiments complemented the vulnerability curves to better understand how anatomy shapes estimates of cavitation resistance. Centrifugation and radial air injection generated acceptable vulnerability curves for the deciduous species, but overestimated drought resistance in the two evergreen ferns. In these hardy plants, axial air injection and bench-top dehydration produced results that most closely aligned with observations in nature. Additional experiments revealed that the dictyostele anatomy impedes air entry into the xylem during spinning and radial air injection. Each method produced acceptable vulnerability curves, depending on the species being tested. Therefore, we stress the importance of validating the curves with in situ measures of water potential and, if possible, hydraulic data to generate realistic results with any of the methods currently available.
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Affiliation(s)
- Jarmila Pittermann
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, 95060, USA
| | - Alex Baer
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, 95060, USA
| | - Ying Sang
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, 95060, USA
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14
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Campany CE, Pittermann J, Baer A, Holmlund H, Schuettpelz E, Mehltreter K, Watkins JE. Leaf water relations in epiphytic ferns are driven by drought avoidance rather than tolerance mechanisms. PLANT, CELL & ENVIRONMENT 2021; 44:1741-1755. [PMID: 33665827 DOI: 10.1111/pce.14042] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 02/22/2021] [Accepted: 02/23/2021] [Indexed: 06/12/2023]
Abstract
Opportunistic diversification has allowed ferns to radiate into epiphytic niches in angiosperm dominated landscapes. However, our understanding of how ecophysiological function allowed establishment in the canopy and the potential transitionary role of the hemi-epiphytic life form remain unclear. Here, we surveyed 39 fern species in Costa Rican tropical forests to explore epiphytic trait divergence in a phylogenetic context. We examined leaf responses to water deficits in terrestrial, hemi-epiphytic and epiphytic ferns and related these findings to functional traits that regulate leaf water status. Epiphytic ferns had reduced xylem area (-63%), shorter stipe lengths (-56%), thicker laminae (+41%) and reduced stomatal density (-46%) compared to terrestrial ferns. Epiphytic ferns exhibited similar turgor loss points, higher osmotic potential at saturation and lower tissue capacitance after turgor loss than terrestrial ferns. Overall, hemi-epiphytic ferns exhibited traits that share characteristics of both terrestrial and epiphytic species. Our findings clearly demonstrate the prevalence of water conservatism in both epiphytic and hemi-epiphytic ferns, via selection for anatomical and structural traits that avoid leaf water stress. Even with likely evolutionarily constrained physiological function, adaptations for drought avoidance have allowed epiphytic ferns to successfully endure the stresses of the canopy habitat.
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Affiliation(s)
- Courtney E Campany
- Department of Biology, Shepherd University, Shepherdstown, West Virginia, USA
- Department of Biology, Colgate University, Hamilton, New York, USA
| | - Jarmila Pittermann
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, California, USA
| | - Alex Baer
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, California, USA
| | - Helen Holmlund
- Natural Science Division, Pepperdine University, Malibu, California, USA
| | - Eric Schuettpelz
- Department of Botany, National Museum of Natural History, Smithsonian Institution, Washington, District of Columbia, USA
| | - Klaus Mehltreter
- Red de Ecología Funcional, Instituto de Ecología A.C., Xalapa, Mexico
- Institute for Systematic Botany and Ecology, University of Ulm, Ulm, Germany
| | - James E Watkins
- Department of Biology, Colgate University, Hamilton, New York, USA
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15
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Fernández-Marín B, Arzac MI, López-Pozo M, Laza JM, Roach T, Stegner M, Neuner G, García-Plazaola JI. Frozen in the dark: interplay of night-time activity of xanthophyll cycle, xylem attributes, and desiccation tolerance in fern resistance to winter. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:3168-3184. [PMID: 33617637 DOI: 10.1093/jxb/erab071] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 02/15/2021] [Indexed: 05/14/2023]
Abstract
While most ferns avoid freezing as they have a tropical distribution or shed their fronds, wintergreen species in temperate and boreoalpine ecosystems have to deal with sub-zero temperatures. Increasing evidence has revealed overlapping mechanisms of desiccation and freezing tolerance in angiosperms, but the physiological mechanisms behind freezing tolerance in ferns are far from clear. We evaluated photochemical and hydraulic parameters in five wintergreen fern species differing in their ability to tolerate desiccation. We assessed frond freezing tolerance, ice nucleation temperature and propagation pattern, and xylem anatomical traits. Dynamics of photochemical performance and xanthophyll cycle were evaluated during freeze-thaw events under controlled conditions and, in selected species, in the field. Only desiccation-tolerant species, which possessed a greater fraction of narrow tracheids (<18 μm) than sensitive species, tolerated freezing. Frond freezing occurred in the field at -3.4 ± 0.9 °C (SD) irrespective of freezing tolerance, freezable water content, or tracheid properties. Even in complete darkness, maximal photochemical efficiency of photosystem II was down-regulated concomitantly with zeaxanthin accumulation in response to freezing. This was reversible upon re-warming only in tolerant species. Our results suggest that adaptation for freezing tolerance is associated with desiccation tolerance through complementary xylem properties (which may prevent risk of irreversible cavitation) and effective photoprotection mechanisms. The latter includes de-epoxidation of xanthophylls in darkness, a process evidenced for the first time directly in the field.
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Affiliation(s)
- Beatriz Fernández-Marín
- Department of Botany, Ecology and Plant Physiology, University of La Laguna (ULL), Tenerife 38200, Spain
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Spain
| | - Miren Irati Arzac
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Spain
| | - Marina López-Pozo
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Spain
| | - José Manuel Laza
- Laboratory of Macromolecular Chemistry (Labquimac), Department of Physical Chemistry, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Spain
| | - Thomas Roach
- Department of Botany and Centre for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Sternwartestrasse 15, 6020 Innsbruck, Austria
| | - Matthias Stegner
- Department of Botany and Centre for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Sternwartestrasse 15, 6020 Innsbruck, Austria
| | - Gilbert Neuner
- Department of Botany and Centre for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Sternwartestrasse 15, 6020 Innsbruck, Austria
| | - José I García-Plazaola
- Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Spain
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16
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Yao GQ, Li FP, Nie ZF, Bi MH, Jiang H, Liu XD, Wei Y, Fang XW. Ethylene, not ABA, is closely linked to the recovery of gas exchange after drought in four Caragana species. PLANT, CELL & ENVIRONMENT 2021; 44:399-411. [PMID: 33131059 DOI: 10.1111/pce.13934] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 10/21/2020] [Indexed: 06/11/2023]
Abstract
Drought is a cyclical phenomenon in natural environments. During dehydration, stomatal closure is mainly regulated by abscisic acid (ABA) dynamics that limit transpiration in seed plants, but following rehydration, the mechanism of gas exchange recovery is still not clear. In this study, leaf water potential (ψleaf ), stomatal conductance (gs ), leaf hydraulic conductance (Kleaf ), foliar ABA level, ethylene emission rate in response to dehydration and rehydration were investigated in four Caragana species with isohydric (Caragana spinosa and C. pruinosa) and anisohydric (C. intermedia and C. microphylla) traits. Two isohydric species with ABA-induced stomatal closure exhibited more sensitive gs and Kleaf to decreasing ψleaf than two anisohydric species which exhibited a switch from ABA to water potential-driven stomatal closure during dehydration. Following rehydration, the recovery of gas exchange was not associated with a decrease in ABA level but was strongly limited by the degradation of the ethylene emission rate in all species. Furthermore, two anisohydric species with low drought-induced ethylene production exhibited more rapid recovery in gas exchange upon rehydration. Our results indicated that ethylene is a key factor regulating the drought-recovery ability in terms of gas exchange, which may shape species adaptation to drought and potential species distribution.
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Affiliation(s)
- Guang-Qian Yao
- State Key Laboratory of Grassland Agro-Ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Feng-Ping Li
- State Key Laboratory of Grassland Agro-Ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Zheng-Fei Nie
- State Key Laboratory of Grassland Agro-Ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Min-Hui Bi
- State Key Laboratory of Grassland Agro-Ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Hui Jiang
- State Key Laboratory of Grassland Agro-Ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Xu-Dong Liu
- State Key Laboratory of Grassland Agro-Ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Yang Wei
- State Key Laboratory of Grassland Agro-Ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Xiang-Wen Fang
- State Key Laboratory of Grassland Agro-Ecosystems, School of Life Sciences, Lanzhou University, Lanzhou, China
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17
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Nitta JH, Watkins JE, Davis CC. Life in the canopy: community trait assessments reveal substantial functional diversity among fern epiphytes. THE NEW PHYTOLOGIST 2020; 227:1885-1899. [PMID: 32285944 DOI: 10.1111/nph.16607] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 04/02/2020] [Indexed: 06/11/2023]
Abstract
The expansion of angiosperm-dominated forests in the Cretaceous and early Cenozoic had a profound effect on terrestrial biota by creating novel ecological niches. The majority of modern fern lineages are hypothesized to have arisen in response to this expansion, particularly fern epiphytes that radiated into the canopy. Recent evidence, however, suggests that epiphytism does not correlate with increased diversification rates in ferns, calling into question the role of the canopy habitat in fern evolution. To understand the role of the canopy in structuring fern community diversity, we investigated functional traits of fern sporophytes and gametophytes across a broad phylogenetic sampling on the island of Moorea, French Polynesia, including > 120 species and representatives of multiple epiphytic radiations. While epiphytes showed convergence in small size and a higher frequency of noncordate gametophytes, they showed greater functional diversity at the community level relative to terrestrial ferns. These results suggest previously overlooked functional diversity among fern epiphytes, and raise the hypothesis that while the angiosperm canopy acted as a complex filter that restricted plant size, it also facilitated diversification into finely partitioned niches. Characterizing these niche axes and adaptations of epiphytic ferns occupying them should be a priority for future pteridological research.
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Affiliation(s)
- Joel H Nitta
- Department of Organismic and Evolutionary Biology and Harvard University Herbaria, Harvard University, 22 Divinity Avenue, Cambridge, MA, 02138, USA
| | - James E Watkins
- Department of Biology, Colgate University, 13 Oak Drive, Hamilton, NY, 13346, USA
| | - Charles C Davis
- Department of Organismic and Evolutionary Biology and Harvard University Herbaria, Harvard University, 22 Divinity Avenue, Cambridge, MA, 02138, USA
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18
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Wilson JP, White JD, Montañez IP, DiMichele WA, McElwain JC, Poulsen CJ, Hren MT. Carboniferous plant physiology breaks the mold. THE NEW PHYTOLOGIST 2020; 227:667-679. [PMID: 32267976 DOI: 10.1111/nph.16460] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 11/17/2019] [Indexed: 06/11/2023]
Abstract
How plants have shaped Earth surface feedbacks over geologic time is a key question in botanical and geological inquiry. Recent work has suggested that biomes during the Carboniferous Period contained plants with extraordinary physiological capacity to shape their environment, contradicting the previously dominant view that plants only began to actively moderate the Earth's surface with the rise of angiosperms during the Mesozoic Era. A recently published Viewpoint disputes this recent work, thus here, we document in detail, the mechanistic underpinnings of our modeling and illustrate the extraordinary ecophysiological nature of Carboniferous plants.
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Affiliation(s)
- Jonathan P Wilson
- Department of Environmental Studies, Haverford College, Haverford, PA, 19041, USA
| | - Joseph D White
- Department of Biology, Baylor University, Waco, TX, 76798, USA
| | - Isabel P Montañez
- Department of Earth and Planetary Sciences, University of California, Davis, CA, 95616, USA
| | - William A DiMichele
- Department of Paleobiology, Smithsonian Museum of Natural History, Washington, DC, 20560, USA
| | - Jennifer C McElwain
- Department of Botany, School of Natural Sciences, Trinity College Dublin, The University of Dublin, Dublin 2, Ireland
| | - Christopher J Poulsen
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Michael T Hren
- Center for Integrative Geosciences, University of Connecticut, Storrs, CT, 06269, USA
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19
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Baer A, Wheeler JK, Pittermann J. Limited hydraulic adjustments drive the acclimation response of Pteridium aquilinum to variable light. ANNALS OF BOTANY 2020; 125:691-700. [PMID: 31956911 PMCID: PMC7102999 DOI: 10.1093/aob/mcaa006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 01/14/2020] [Indexed: 05/27/2023]
Abstract
BACKGROUND AND AIMS The success of invasive plants can be attributed to many traits including the ability to adapt to variable environmental conditions. Whether by adaptation, acclimation or phenotypic plasticity, these plants often increase their resource-use efficiency and, consequently, their fitness. The goal of this study was to examine the hydraulic and eco-physiological attributes of sun and shade populations of Pteridium aquilinum, a weedy fern, to determine whether the presence of vessels and other hydraulic attributes affects its success under a variety of light conditions. METHODS Hydraulic traits such as cavitation resistance, hydraulic conductivity, photosynthesis and water potential at turgor loss point were measured on fronds from sun and shade populations. Anatomical and structural traits such as conduit diameter and length, stomatal density and vein density were also recorded. Diurnal measures of leaf water potential and stomatal conductance complement these data. KEY RESULTS Gas exchange was nearly double in the sun plants, as was water-use efficiency, leaf-specific conductivity, and stomatal and vein density. This was largely achieved by a decrease in leaf area, coupled with higher xylem content. There was no significant difference in petiole cavitation resistance between the sun and shade leaves, nor in xylem-specific conductivity. Hydraulic conduit diameters were nearly equivalent in the two leaf types. CONCLUSIONS Shifts in leaf area and xylem content allow P. aquilinum to occupy habitats with full sun, and to adjust its physiology accordingly. High rates of photosynthesis explain in part the success of this fern in disturbed habitats, although no change was observed in intrinsic xylem qualities such as cavitation resistance or conduit length. This suggests that P. aquilinum is constrained by its fundamental body plan, in contrast to seed plants, which show greater capacity for hydraulic adjustment.
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Affiliation(s)
- Alex Baer
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
| | - James K Wheeler
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
| | - Jarmila Pittermann
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, USA
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20
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Holmlund HI, Davis SD, Ewers FW, Aguirre NM, Sapes G, Sala A, Pittermann J. Positive root pressure is critical for whole-plant desiccation recovery in two species of terrestrial resurrection ferns. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:1139-1150. [PMID: 31641748 PMCID: PMC6977189 DOI: 10.1093/jxb/erz472] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Accepted: 10/10/2019] [Indexed: 05/26/2023]
Abstract
Desiccation-tolerant (DT) organisms can lose nearly all their water without dying. Desiccation tolerance allows organisms to survive in a nearly completely dehydrated, dormant state. At the cellular level, sugars and proteins stabilize cellular components and protect them from oxidative damage. However, there are few studies of the dynamics and drivers of whole-plant recovery in vascular DT plants. In vascular DT plants, whole-plant desiccation recovery (resurrection) depends not only on cellular rehydration, but also on the recovery of organs with unequal access to water. In this study, in situ natural and artificial irrigation experiments revealed the dynamics of desiccation recovery in two DT fern species. Organ-specific irrigation experiments revealed that the entire plant resurrected when water was supplied to roots, but leaf hydration alone (foliar water uptake) was insufficient to rehydrate the stele and roots. In both species, pressure applied to petioles of excised desiccated fronds resurrected distal leaf tissue, while capillarity alone was insufficient to resurrect distal pinnules. Upon rehydration, sucrose levels in the rhizome and stele dropped dramatically as starch levels rose, consistent with the role of accumulated sucrose as a desiccation protectant. These findings provide insight into traits that facilitate desiccation recovery in dryland ferns associated with chaparral vegetation of southern California.
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Affiliation(s)
| | | | - Frank W Ewers
- California State Polytechnic University, Pomona, Pomona, CA, USA
| | | | | | - Anna Sala
- University of Montana, Missoula, MT, USA
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21
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Kübarsepp L, Laanisto L, Niinemets Ü, Talts E, Tosens T. Are stomata in ferns and allies sluggish? Stomatal responses to CO 2 , humidity and light and their scaling with size and density. THE NEW PHYTOLOGIST 2020; 225:183-195. [PMID: 31479517 DOI: 10.1111/nph.16159] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 08/15/2019] [Indexed: 06/10/2023]
Abstract
Fast stomatal reactions enable plants to successfully cope with a constantly changing environment yet there is an ongoing debate on the stomatal regulation mechanisms in basal plant groups. We measured stomatal morphological parameters in 29 fern and allied species from temperate to tropical biomes and two outgroup angiosperm species. Stomatal dynamic responses to environmental drivers were measured in 16 ferns and the two angiosperms using a gas-exchange system. Principal components analyses were used to further reveal the structure-function relationships in stomata. We show a > 10-fold variation for stomatal opening delays and 20-fold variation for stomatal closing delays in ferns. Across species, stomatal responses to vapor pressure deficit (VPD) were the fastest, while light and [CO2 ] responses were slower. In most cases the outgroup species' reaction speeds to changes in environmental variables were similar to those of ferns. Correlations between stomatal response rate and size were apparent for stomatal opening in light and low [CO2 ] while not evident for closing reactions and changes in VPD. No correlations between stomatal density and response speed were observed. Together, this study demonstrates different mechanisms controlling stomatal reactions in ferns at different environmental stimuli, which should be considered in future studies relating stomatal morphology and function.
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Affiliation(s)
- Liisa Kübarsepp
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu, 51014, Estonia
| | - Lauri Laanisto
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu, 51014, Estonia
| | - Ülo Niinemets
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu, 51014, Estonia
- Estonian Academy of Sciences, Kohtu 6, Tallinn, 10130, Estonia
| | - Eero Talts
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu, 51014, Estonia
| | - Tiina Tosens
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu, 51014, Estonia
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22
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Sareen B, Thapa P, Joshi R, Bhattacharya A. Proteome Analysis of the Gametophytes of a Western Himalayan Fern Diplazium maximum Reveals Their Adaptive Responses to Changes in Their Micro-Environment. FRONTIERS IN PLANT SCIENCE 2019; 10:1623. [PMID: 31921265 PMCID: PMC6928197 DOI: 10.3389/fpls.2019.01623] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2019] [Accepted: 11/19/2019] [Indexed: 06/10/2023]
Abstract
Ferns have survived changing habitats and environmental extremes of different eras, wherein, the exploratory haploid gametophytes are believed to have played a major role. Therefore, the proteome of in vitro grown gametophytes of a temperate Himalayan fern, Diplazium maximum in response to 0 (G0), 1 (G1), and 3% (G3) sucrose was studied. A total of 110 differentially abundant protein spots (DAPs) were obtained. Among these, only 67 could be functionally categorized as unique proteins involved in various metabolic processes. Calcium dependent proteins, receptor like kinases, G proteins, proteins related to hormonal signaling and their interaction with other pathways, and regulatory proteins were recorded indicating the involvement of five different signaling pathways. DAPs involved in the activation of genes and transcription factors of signaling and transduction pathways, transport and ion channels, cell-wall and structural proteins, defense, chaperons, energy metabolism, protein synthesis, modification, and turnover were identified. The gametophytes responded to changes in their micro-environment. There was also significant increase in prothallus biomass and conversion of two-dimensional prothalli into three-dimensional prothallus clumps at 3% sucrose. The three-D clumps had higher photosynthetic surface area and also closer proximity for sexual reproduction and sporophyte formation. Highest accumulation of proline, enhanced scavenging of reactive oxygen species (ROS) and DAPs of mostly, abiotic stress tolerance, secondary metabolite synthesis, and detoxification at 3% sucrose indicated an adaptive response of gametophytes. Protein Protein Interaction network and Principal Component analyses, and qRT-PCR validation of genes encoding 12 proteins of various metabolic processes indicated differential adjustment of gametophytes to different levels of sucrose in the culture medium. Therefore, a hypothetical mechanism was proposed to show that even slight changes in the micro-environment of D. maximum gametophytes triggered multiple mechanisms of adaptation. Many DAPs identified in the study have potential use in crop improvement and metabolic engineering programs, phytoremediation and environmental protection.
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Affiliation(s)
- Bhuvnesh Sareen
- Division of Biotechnology, CSIR-Institute of Himalayan Bioresource Technology, Palampur, India
- Department of Biotechnology, Guru Nanak Dev University, Amritsar, India
| | - Pooja Thapa
- Division of Biotechnology, CSIR-Institute of Himalayan Bioresource Technology, Palampur, India
- Department of Biotechnology, Guru Nanak Dev University, Amritsar, India
| | - Robin Joshi
- Division of Biotechnology, CSIR-Institute of Himalayan Bioresource Technology, Palampur, India
| | - Amita Bhattacharya
- Division of Biotechnology, CSIR-Institute of Himalayan Bioresource Technology, Palampur, India
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23
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Watts JL, Moran RC, Watkins JE. Hymenasplenium volubile: documentation of its gametophytes and the first record of a hemiepiphyte in the Aspleniaceae. ANNALS OF BOTANY 2019; 124:829-835. [PMID: 31630154 PMCID: PMC6868390 DOI: 10.1093/aob/mcz124] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 10/18/2019] [Indexed: 05/27/2023]
Abstract
BACKGROUND AND AIMS Through careful field examination of the growth habit of the gametophytes and sporophytes of Hymenasplenium volubile across an ontogenetic series, we aim to understand better the evolution of epiphytism in this poorly understood group of ferns. METHODS We made field observations of H. volubile sporophytes and gametophytes, and brought specimens back to the lab for microscopic analysis. In the field, sporophytes at each ontogenetic stage were photographed to document the species' growth habit. We used an existing phylogeny to optimize growth form of New World Hymenasplenium. KEY RESULTS Young sporophytes were at first fully epiphytic and produced one or two long feeding roots that extend to the soil where they branch profusely. The feeding roots remain in contact with the soil throughout the life of the plant. Thus, H. volubile is a hemiepiphyte. While immature, gametophytes are appressed to the tree trunk, but, as their gametangia mature, their lower margin lifts upward, imparting a shelf-like appearance to the thallus. The thallus attaches to the substrate by branched rhizoids produced along the margin of the thallus in contact with the substrate. CONCLUSIONS Hemiepiphytes are a key link in the evolution of epiphytic ferns and may act as a bridge between the forest floor and the canopy. Our finding is the first report of hemiepiphytism in Aspleniaceae, a large lineage with many epiphytic and terrestrial taxa. This work serves as an important model to understand the evolution of epiphytism in this group specifically and in ferns in general. The majority of our understanding of fern gametophyte biology is derived from laboratory studies. Our efforts represent a fundamental contribution to understanding fern gametophyte ecology in a field setting.
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Affiliation(s)
- Jacob L Watts
- Colgate University, Department of Biology, Hamilton, NY, USA
| | | | - James E Watkins
- Colgate University, Department of Biology, Hamilton, NY, USA
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24
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Nitta JH, Ebihara A. Virtual issue: Ecology and evolution of pteridophytes in the era of molecular genetics. JOURNAL OF PLANT RESEARCH 2019; 132:719-721. [PMID: 31595362 DOI: 10.1007/s10265-019-01139-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The past quarter-century has witnessed a revolution in our understanding of the phylogenetics, systematics, and ecology of pteridophytes (ferns and lycophytes), particularly due to the rapid accumulation of plastid sequence data and a renewed interest in the ecology of the sexual phase of the life cycle. We here compile 19 papers recently published in the Journal of Plant Research dealing with the biology of pteridophytes, grouped into six categories: (1) breeding systems, (2) species complexes and polyploidization, (3) fossil taxa, (4) gametophyte ecology, (5) systematics, (6) biodiversity. We hope this collection of papers will be of value to researchers interested in this fascinating group of plants.
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Affiliation(s)
- Joel H Nitta
- Department of Botany, National Museum of Natural History, Smithsonian Institution, Washington, DC, 20013, USA.
| | - Atsushi Ebihara
- Department of Botany, National Museum of Nature and Science, 4-1-1 Amakubo, Tsukuba, Ibaraki, 305-0005, Japan
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25
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Olson ME, Pittermann J. Cheap and attractive: water relations and floral adaptation. THE NEW PHYTOLOGIST 2019; 223:8-10. [PMID: 31032932 DOI: 10.1111/nph.15839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Affiliation(s)
- Mark E Olson
- Instituto de Biologia, Universidad Nacional Autonoma de Mexico, Tercer Circuito sin de CU, Mexico City, DF, 04510, Mexico
| | - Jarmila Pittermann
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, 95060, USA
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26
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Brock JMR, Burns BR, Perry GLW, Lee WG. Gametophyte niche differences among sympatric tree ferns. Biol Lett 2019; 15:20180659. [PMID: 30958217 PMCID: PMC6371912 DOI: 10.1098/rsbl.2018.0659] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 12/19/2018] [Indexed: 11/12/2022] Open
Abstract
Forest community assembly is usually framed in terms of sporophyte dynamics; however, the recruitment and maintenance of fern populations, frequently influential in forest composition and structure, are initially determined by gametophytes. Sporophytes of three Cyathea tree fern species show habitat partitioning along gradients of phosphorus and light; we asked whether gametophyte niche differences parallel this pattern. To compare niche characteristics among taxa we compared growth rates to a size threshold (≥3 mm) of gametophytes under controlled conditions using a multi-factorial, multi-level (3 × 4) experiment, varying irradiance (5.4 ± 4.4; 59.1 ± 44.3; 107 ± 74.1 µmol m-2 s-1) and orthophosphate concentrations (5, 10, 20, 40 mg kg-1). Gametophytes of the pioneer species C. medullaris developed to the size threshold across a broad range of phosphate and irradiance treatments (more than 20% of gametophytes in ≥ 7 of the 12 treatments), peaking at 20 mg kg-1 P and 60 µmol m-2 s-1 irradiance. The growth rates of the forest understorey species C. dealbata and C. smithii also peaked at 60 µmol m-2 s-1 but varied across treatments, suggesting niche differentiation along irradiance and orthophosphate gradients. Our analysis suggests that gametophyte development is strategically aligned to the ecological habits of sporophytes and that forest community assembly is likely strongly influenced by the independent gametophyte life-stage.
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Affiliation(s)
- James M. R. Brock
- School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - Bruce R. Burns
- School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - George L. W. Perry
- School of Environment, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
| | - William G. Lee
- School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
- Landcare Research, Private Bag 1930, Dunedin 9054, New Zealand
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Niinemets Ü, Bravo LA, Copolovici L. Changes in photosynthetic rate and stress volatile emissions through desiccation-rehydration cycles in desiccation-tolerant epiphytic filmy ferns (Hymenophyllaceae). PLANT, CELL & ENVIRONMENT 2018; 41:1605-1617. [PMID: 29603297 PMCID: PMC6047733 DOI: 10.1111/pce.13201] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 03/20/2018] [Indexed: 05/25/2023]
Abstract
Exposure to recurrent desiccation cycles carries a risk of accumulation of reactive oxygen species that can impair leaf physiological activity upon rehydration, but changes in filmy fern stress status through desiccation and rewatering cycles have been poorly studied. We studied foliage photosynthetic rate and volatile marker compounds characterizing cell wall modifications (methanol) and stress development (lipoxygenase [LOX] pathway volatiles and methanol) through desiccation-rewatering cycles in lower-canopy species Hymenoglossum cruentum and Hymenophyllum caudiculatum, lower- to upper-canopy species Hymenophyllum plicatum and upper-canopy species Hymenophyllum dentatum sampled from a common environment and hypothesized that lower canopy species respond more strongly to desiccation and rewatering. In all species, rates of photosynthesis and LOX volatile emission decreased with progression of desiccation, but LOX emission decreased with a slower rate than photosynthesis. Rewatering first led to an emission burst of LOX volatiles followed by methanol, indicating that the oxidative burst was elicited in the symplast and further propagated to cell walls. Changes in LOX emissions were more pronounced in the upper-canopy species that had a greater photosynthetic activity and likely a greater rate of production of photooxidants. We conclude that rewatering induces the most severe stress in filmy ferns, especially in the upper canopy species.
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Affiliation(s)
- Ülo Niinemets
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu, 51014, Estonia
- Estonian Academy of Sciences, Kohtu 6, Tallinn, 10130, Estonia
| | - León A Bravo
- Departamento de Ciencias, Agronómicas y Recursos Naturales, Facultad de Ciencias Agropecuarias y Forestales, and Center of Plant, Soil Interaction and Natural Resources Biotechnology, Scientific and Technological Bioresource Nucleus, Universidad de La Frontera, Temuco, 1145, Chile
| | - Lucian Copolovici
- Faculty of Food Engineering, Tourism and Environmental Protection, Institute of Research, Innovation and Development in Technical and Natural Sciences, "Aurel Vlaicu" University, Romania, 2 Elena Dragoi, Arad, 310330, Romania
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Babenko LM, Romanenko KO, Shcherbatiuk MM, Vasheka OV, Romanenko PO, Negretsky VA, Kosakivska IV. Effects of Exogenous Phytohormones on Spore Germination and Morphogenesis of Polystichum aculeatum (L.) Roth Gametophyte in vitro Culture. CYTOL GENET+ 2018. [DOI: 10.3103/s0095452718020032] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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29
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Klein T, Zeppel MJB, Anderegg WRL, Bloemen J, De Kauwe MG, Hudson P, Ruehr NK, Powell TL, von Arx G, Nardini A. Xylem embolism refilling and resilience against drought-induced mortality in woody plants: processes and trade-offs. Ecol Res 2018. [DOI: 10.1007/s11284-018-1588-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Testo WL, Sundue MA. Are rates of species diversification and body size evolution coupled in the ferns? AMERICAN JOURNAL OF BOTANY 2018; 105:525-535. [PMID: 29637539 DOI: 10.1002/ajb2.1044] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 11/09/2017] [Indexed: 06/08/2023]
Abstract
PREMISE OF THE STUDY Understanding the relationship between phenotypic evolution and lineage diversification is a central goal of evolutionary biology. To extend our understanding of the role morphological evolution plays in the diversification of plants, we examined the relationship between leaf size evolution and lineage diversification across ferns. METHODS We tested for an association between body size evolution and lineage diversification using a comparative phylogenetic approach that combined a time-calibrated phylogeny and leaf size data set for 2654 fern species. Rates of leaf size change and lineage diversification were estimated using BAMM, and rate correlations were performed for rates obtained for all families and individual species. Rates and patterns of rate-rate correlation were also analyzed separately for terrestrial and epiphytic taxa. KEY RESULTS We find no significant correlation between rates of leaf area change and lineage diversification, nor was there a difference in this pattern when growth habit is considered. Our results are consistent with the findings of an earlier study that reported decoupled rates of body size evolution and diversification in the Polypodiaceae, but conflict with a recent study that reported a positive correlation between body size evolution and lineage diversification rates in the tree fern family Cyatheaceae. CONCLUSIONS Our findings indicate that lineage diversification in ferns is largely decoupled from shifts in body size, in contrast to several other groups of organisms. Speciation in ferns appears to be primarily driven by hybridization and isolation along elevational gradients, rather than adaptive radiations featuring prominent morphological restructuring. The exceptional diversity of leaf morphologies in ferns appears to reflect a combination of ecophysiological constraints and adaptations that are not key innovations.
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Affiliation(s)
- Weston L Testo
- The Pringle Herbarium, University of Vermont, 27 Colchester Drive, Burlington, VT, 05405, USA
| | - Michael A Sundue
- The Pringle Herbarium, University of Vermont, 27 Colchester Drive, Burlington, VT, 05405, USA
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Sessa EB, Chambers SM, Li D, Trotta L, Endara L, Burleigh JG, Baiser B. Community assembly of the ferns of Florida. AMERICAN JOURNAL OF BOTANY 2018; 105:549-564. [PMID: 29730880 DOI: 10.1002/ajb2.1073] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 01/18/2018] [Indexed: 06/08/2023]
Abstract
PREMISE OF THE STUDY Many ecological and evolutionary processes shape the assembly of organisms into local communities from a regional pool of species. We analyzed phylogenetic and functional diversity to understand community assembly of the ferns of Florida at two spatial scales. METHODS We built a phylogeny for 125 of the 141 species of ferns in Florida using five chloroplast markers. We calculated mean pairwise dissimilarity (MPD) and mean nearest taxon distance (MNTD) from phylogenetic distances and functional trait data for both spatial scales and compared the results to null models to assess significance. KEY RESULTS Our results for over vs. underdispersion in functional and phylogenetic diversity differed depending on spatial scale and metric considered. At the county scale, MPD revealed evidence for phylogenetic overdispersion, while MNTD revealed phylogenetic and functional underdispersion, and at the conservation area scale, MPD revealed phylogenetic and functional underdispersion while MNTD revealed evidence only of functional underdispersion. CONCLUSIONS Our results are consistent with environmental filtering playing a larger role at the smaller, conservation area scale. The smaller spatial units are likely composed of fewer local habitat types that are selecting for closely related species, with the larger-scale units more likely to be composed of multiple habitat types that bring together a larger pool of species from across the phylogeny. Several aspects of fern biology, including their unique physiology and water relations and the importance of the independent gametophyte stage of the life cycle, make ferns highly sensitive to local, microhabitat conditions.
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Affiliation(s)
- Emily B Sessa
- Department of Biology, University of Florida, 220 Bartram Hall, Gainesville, FL, 32611, USA
| | - Sally M Chambers
- Department of Biology, University of Florida, 220 Bartram Hall, Gainesville, FL, 32611, USA
- Marie Selby Botanical Gardens, 900 S. Palm Avenue, Sarasota, FL, 34236, USA
| | - Daijiang Li
- Department of Wildlife Ecology & Conservation, University of Florida, 110 Newins-Ziegler Hall, Gainesville, FL, 32611, USA
| | - Lauren Trotta
- Department of Wildlife Ecology & Conservation, University of Florida, 110 Newins-Ziegler Hall, Gainesville, FL, 32611, USA
| | - Lorena Endara
- Department of Biology, University of Florida, 220 Bartram Hall, Gainesville, FL, 32611, USA
| | - J Gordon Burleigh
- Department of Biology, University of Florida, 220 Bartram Hall, Gainesville, FL, 32611, USA
| | - Benjamin Baiser
- Department of Wildlife Ecology & Conservation, University of Florida, 110 Newins-Ziegler Hall, Gainesville, FL, 32611, USA
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Raven JA. Evolution and palaeophysiology of the vascular system and other means of long-distance transport. Philos Trans R Soc Lond B Biol Sci 2018; 373:20160497. [PMID: 29254962 PMCID: PMC5745333 DOI: 10.1098/rstb.2016.0497] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/11/2017] [Indexed: 12/13/2022] Open
Abstract
Photolithotrophic growth on land using atmospheric CO2 inevitably involves H2O vapour loss. Embryophytes greater than or equal to 100 mm tall are homoiohydric and endohydric with mass flow of aqueous solution through the xylem in tracheophytes. Structural details in Rhynie sporophytes enable modelling of the hydraulics of H2O supply to the transpiring surface, and the potential for gas exchange with the Devonian atmosphere. Xylem carrying H2O under tension involves programmed cell death, rigid cell walls and embolism repair; fossils provide little evidence on these functions other than the presence of lignin. The phenylalanine ammonia lyase essential for lignin synthesis came from horizontal gene transfer. Rhynie plants lack endodermes, limiting regulation of the supply of soil nutrients to shoots. The transfer of organic solutes from photosynthetic sites to growing and storage tissues involves mass flow through phloem in extant tracheophytes. Rhynie plants show little evidence of phloem; possible alternatives for transport of organic solutes are discussed. Extant examples of the arbuscular mycorrhizas found in Rhynie plants exchange soil-derived nutrients (especially P) for plant-derived organic matter, involving bidirectional mass flow along the hyphae. The aquatic cyanobacteria and the charalean Palaeonitella at Rhynie also have long-distance (relative to the size of the organism) transport.This article is part of a discussion meeting issue 'The Rhynie cherts: our earliest terrestrial ecosystem revisited'.
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Affiliation(s)
- John A Raven
- Division of Plant Sciences, University of Dundee at the James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK
- School of Biological Sciences, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
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Costa MCD, Cooper K, Hilhorst HWM, Farrant JM. Orthodox Seeds and Resurrection Plants: Two of a Kind? PLANT PHYSIOLOGY 2017; 175:589-599. [PMID: 28851758 PMCID: PMC5619911 DOI: 10.1104/pp.17.00760] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 08/22/2017] [Indexed: 05/27/2023]
Abstract
Understanding shared strategies for desiccation tolerance in orthodox seeds and resurrection plants can yield insights for agricultural improvement.
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Affiliation(s)
- Maria-Cecília D Costa
- Department of Molecular and Cell Biology, University of Cape Town, 7701 Cape Town, South Africa
| | - Keren Cooper
- Department of Molecular and Cell Biology, University of Cape Town, 7701 Cape Town, South Africa
| | - Henk W M Hilhorst
- Laboratory of Plant Physiology, Wageningen University, 6708PB Wageningen, The Netherlands
| | - Jill M Farrant
- Department of Molecular and Cell Biology, University of Cape Town, 7701 Cape Town, South Africa
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Nitta JH, Meyer J, Taputuarai R, Davis CC. Life cycle matters:
DNA
barcoding reveals contrasting community structure between fern sporophytes and gametophytes. ECOL MONOGR 2017. [DOI: 10.1002/ecm.1246] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Joel H. Nitta
- Department of Organismic and Evolutionary Biology and Harvard University Herbaria Harvard University Cambridge Massachusetts 02138 USA
| | - Jean‐Yves Meyer
- Délégation à la Recherche Government of French Polynesia B.P. 20981 Papeete, Tahiti French Polynesia
| | - Ravahere Taputuarai
- Association Te Rau Ati Ati a Tau a Hiti Noa Tu B.P. 11553 Mahina, Tahiti French Polynesia
| | - Charles C. Davis
- Department of Organismic and Evolutionary Biology and Harvard University Herbaria Harvard University Cambridge Massachusetts 02138 USA
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35
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Burns EE, Pittermann J, Rico C. Evergreen and Deciduous Ferns of the Coast Redwood Forest. ACTA ACUST UNITED AC 2016. [DOI: 10.3120/0024-9637-63.4.329] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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36
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Haufler CH, Pryer KM, Schuettpelz E, Sessa EB, Farrar DR, Moran R, Schneller JJ, Watkins JE, Windham MD. Sex and the Single Gametophyte: Revising the Homosporous Vascular Plant Life Cycle in Light of Contemporary Research. Bioscience 2016. [DOI: 10.1093/biosci/biw108] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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37
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Sessa EB, Testo WL, Watkins JE. On the widespread capacity for, and functional significance of, extreme inbreeding in ferns. THE NEW PHYTOLOGIST 2016; 211:1108-1119. [PMID: 27094807 DOI: 10.1111/nph.13985] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 03/18/2016] [Indexed: 06/05/2023]
Abstract
Homosporous vascular plants utilize three different mating systems, one of which, gametophytic selfing, is an extreme form of inbreeding only possible in homosporous groups. This mating system results in complete homozygosity in all progeny and has important evolutionary and ecological implications. Ferns are the largest group of homosporous land plants, and the significance of extreme inbreeding for fern evolution has been a subject of debate for decades. We cultured gametophytes in the laboratory and quantified the relative frequencies of sporophyte production from isolated and paired gametophytes, and examined associations between breeding systems and several ecological and evolutionary traits. The majority of fern species studied show a capacity for gametophytic selfing, producing sporophytes from both isolated and paired gametophytes. While we did not follow sporophytes to maturity to investigate potential detrimental effects of homozygosity at later developmental stages, our results suggest that gametophytic selfing may have greater significance for fern evolution and diversification than has previously been realized. We present evidence from the largest study of mating behavior in ferns to date that the capacity for extreme inbreeding is prevalent in this lineage, and we discuss its implications and relevance and make recommendations for future studies of fern mating systems.
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Affiliation(s)
- Emily B Sessa
- Department of Biology, University of Florida, Box 118525, Gainesville, FL 32611, USA
| | - Weston L Testo
- Department of Plant Biology, University of Vermont, 111 Jeffords Hall, 63 Carrigan Drive, Burlington, VT, 05405, USA
| | - James E Watkins
- Biology Department, Colgate University, 129 Ho Science Center, 13 Oak Drive, Hamilton, NY, 13346, USA
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38
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Franks PJ, Britton-Harper ZJ. No evidence of general CO2 insensitivity in ferns: one stomatal control mechanism for all land plants? THE NEW PHYTOLOGIST 2016; 211:819-27. [PMID: 27214852 DOI: 10.1111/nph.14020] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 04/19/2016] [Indexed: 05/21/2023]
Abstract
Stomatal regulation of plant carbon uptake and water loss under changing environmental conditions was a crucial evolutionary step in the colonization of land by plants. There are currently two conflicting models describing the nature of stomatal regulation across terrestrial vascular plants: the first is characterized by a fundamental mechanistic similarity across all lineages, and the second is characterized by the evolution of major differences in angiosperms compared with more ancient lineages. Specifically, the second model posits that stomata of ferns lack a response to elevated atmospheric CO2 concentration (ca ) and therefore cannot regulate leaf intercellular CO2 concentration (ci ). We compared stomatal sensitivity to changes in ca in three distantly related fern species and a representative angiosperm species. Fern and angiosperm stomata responded strongly and similarly to changes in ca . As a result, ci /ca was maintained within narrow limits during ca changes. Our results challenge the model in which stomata of ferns generally lack a response to elevated ca and that angiosperms evolved new dynamic mechanisms for regulating leaf gas exchange that differ fundamentally from ferns. Instead, the results are consistent with a universal stomatal control mechanism that is fundamentally conserved across ferns and angiosperms, and therefore likely all vascular plant divisions.
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Affiliation(s)
- Peter J Franks
- Faculty of Agriculture and Environment, University of Sydney, Sydney, NSW, 2006, Australia
| | - Zoe J Britton-Harper
- Faculty of Agriculture and Environment, University of Sydney, Sydney, NSW, 2006, Australia
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Baer A, Wheeler JK, Pittermann J. Not dead yet: the seasonal water relations of two perennial ferns during California's exceptional drought. THE NEW PHYTOLOGIST 2016; 210:122-132. [PMID: 26660879 DOI: 10.1111/nph.13770] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 10/17/2015] [Indexed: 06/05/2023]
Abstract
The understory of the redwood forests of California's coast harbors perennial ferns, including Polystichum munitum and Dryopteris arguta. Unusual for ferns, these species are adapted to the characteristic Mediterranean-type dry season, but the mechanisms of tolerance have not been studied. The water relations of P. munitum and D. arguta were surveyed for over a year, including measures of water potential (Ψ), stomatal conductance (gs) and frond stipe hydraulic conductivity (K). A dehydration and re-watering experiment on potted P. munitum plants corroborated the field data. The seasonal Ψ varied from 0 to below -3 MPa in both species, with gs and K generally tracking Ψ; the loss of K rarely exceeded 80%. Quantile regression analysis showed that, at the 0.1 quantile, 50% of K was lost at -2.58 and -3.84 MPa in P. munitum and D. arguta, respectively. The hydraulic recovery of re-watered plants was attributed to capillarity. The seasonal water relations of P. munitum and D. arguta are variable, but consistent with laboratory-based estimates of drought tolerance. Hydraulic and Ψ recovery following rain allows perennial ferns to survive severe drought, but prolonged water deficit, coupled with insect damage, may hamper frond survival. The legacy effects of drought on reproductive capacity and community dynamics are unknown.
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Affiliation(s)
- Alex Baer
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, 95064, USA
| | - James K Wheeler
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, 95064, USA
| | - Jarmila Pittermann
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, 95064, USA
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40
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Zhang KM, Shen Y, Fang YM, Liu Y. Changes in gametophyte physiology of Pteris multifida induced by the leaf leachate treatment of the invasive Bidens pilosa. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:3578-85. [PMID: 26490937 DOI: 10.1007/s11356-015-5589-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 09/20/2015] [Indexed: 05/26/2023]
Abstract
In recent years, the response of fern gametophytes to environment has raised much attention. However, studies on the influence of plant invasion to fern gametophytes are scarce. Allelopathy plays an important role in biological invasion. Hence, it is necessary to study the allelopathic effects of invasive plants on fern gametophytes and elucidate the mechanisms by which invasive plants cause phytotoxicity. As one of the main invasive plants in China, Bidens pilosa exhibits allelopathic effects on spermatophyte growth. Field investigation shows that many ferns are threatened by the invasion of B. pilosa. The distribution of Pteris multifida overlaps with that of B. pilosa in China. To examine the potential involvement of allelopathic mechanisms of B. pilosa leaves, changes in the physiology in P. multifida gametophytes are analyzed. We found that cell membrane and antioxidant enzyme activities as well as photosynthesis pigment contents of the gametophytes were affected by B. pilosa leachates. Gametophytes of P. multifida exposed to B. pilosa had increased damages to cell membranes, expressed in thiobarbituric acid reacting substance (TBARS) concentrations, malondialdehyde (MDA), electrolyte leakage (membrane permeability), and degree of injury. Enzyme activities, assessed by superoxide dismutase (SOD) and catalase (CAT) as well as guaiacol peroxidase (GPX) enhanced with the increase in leachate concentration after 2-day exposure. Meanwhile, lower chlorophyll a (Chl a), chlorophyll b (Chl b), carotenoid (Car), and the total chlorophyll were measured as leachate concentrations increased. At day 10, leaf leachates of B. pilosa exhibited the greatest inhibition. These results suggest that the observed inhibitory or stimulatory effects on the physiology studied can have an adverse effect on P. multifida and that allelopathic interference seems to have involved in this process.
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Affiliation(s)
- Kai-Mei Zhang
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, 210037, Jiangsu, China
- College of Biology and the Environment, Nanjing Forestry University, Nanjing, 210037, Jiangsu, China
- Department of Botany, Smithsonian Institution, Washington, DC, 20013, USA
| | - Yu Shen
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, 210037, Jiangsu, China
- College of Biology and the Environment, Nanjing Forestry University, Nanjing, 210037, Jiangsu, China
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Yan-Ming Fang
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, 210037, Jiangsu, China.
- College of Biology and the Environment, Nanjing Forestry University, Nanjing, 210037, Jiangsu, China.
| | - Ying Liu
- Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, 210037, Jiangsu, China
- College of Biology and the Environment, Nanjing Forestry University, Nanjing, 210037, Jiangsu, China
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41
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Brodersen CR, Rico C, Guenni O, Pittermann J. Embolism spread in the primary xylem of Polystichum munitum: implications for water transport during seasonal drought. PLANT, CELL & ENVIRONMENT 2016; 39:338-346. [PMID: 26227010 DOI: 10.1111/pce.12618] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 07/19/2015] [Accepted: 07/21/2015] [Indexed: 06/04/2023]
Abstract
Xylem network structure and function have been characterized for many woody plants, but less is known about fern xylem, particularly in species endemic to climates where water is a limiting resource for months at a time. We characterized seasonal variability in soil moisture and frond water status in a common perennial fern in the redwood understory of a costal California, and then investigated the consequences of drought-induced embolism on vascular function. Seasonal variability in air temperature and soil water content was minimal, and frond water potential declined slowly over the observational period. Our data show that Polystichum munitum was protected from significant drought-induced hydraulic dysfunction during this growing season because of a combination of cavitation resistant conduits (Air-seeding threshold (ASP) = -1.53 MPa; xylem pressure inducing 50% loss of hydraulic conductivity (P50 ) = -3.02 MPa) and a soil with low moisture variability. High resolution micro-computed tomography (MicroCT) imaging revealed patterns of embolism formation in vivo for the first time in ferns providing insight into the functional status of the xylem network under drought conditions. Together with stomatal conductance measurements, these data suggest that P. munitum is adapted to tolerate drier conditions than what was observed during the growing season.
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Affiliation(s)
- Craig R Brodersen
- School of Forestry and Environmental Studies, Yale University, New Haven, CT, 06511, USA
| | | | - Orlando Guenni
- Universidad Central de Venezuela, Facultad de Agronomía, Instituto de Botánica Agrícola, Maracay, 2101, Venezuela
| | - Jarmila Pittermann
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, 95064, USA
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Zier J, Belanger B, Trahan G, Watkins JE. Ecophysiology of four co-occurring lycophyte species: an investigation of functional convergence. AOB PLANTS 2015; 7:plv137. [PMID: 26602987 PMCID: PMC4689120 DOI: 10.1093/aobpla/plv137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 11/07/2015] [Indexed: 05/26/2023]
Abstract
Lycophytes are the most early divergent extant lineage of vascular land plants. The group has a broad global distribution ranging from tundra to tropical forests and can make up an important component of temperate northeast US forests. We know very little about the in situ ecophysiology of this group and apparently no study has evaluated if lycophytes conform to functional patterns expected by the leaf economics spectrum hypothesis. To determine factors influencing photosynthetic capacity (Amax), we analysed several physiological traits related to photosynthesis to include stomatal, nutrient, vascular traits, and patterns of biomass distribution in four coexisting temperate lycophyte species: Lycopodium clavatum, Spinulum annotinum, Diphasiastrum digitatum and Dendrolycopodium dendroideum. We found no difference in maximum photosynthetic rates across species, yet wide variation in other traits. We also found that Amax was not related to leaf nitrogen concentration and is more tied to stomatal conductance, suggestive of a fundamentally different sets of constraints on photosynthesis in these lycophyte taxa compared with ferns and seed plants. These findings complement the hydropassive model of stomatal control in lycophytes and may reflect canalization of function in this group. Our data also demonstrate functional ecological similarities: De. dendroideum and D. digitatum are species that have substantial belowground biomass investment and are consistently more similar to each other across multiple traits than either is to the more surficial S. annotinum and L. clavatum. Such differences may partition environments in ways that allow for the close coexistence of these species.
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Affiliation(s)
- Jacqlynn Zier
- Department of Biology, Colgate University, Hamilton, NY 13346, USA
| | - Bryce Belanger
- Department of Biology, Colgate University, Hamilton, NY 13346, USA
| | - Genevieve Trahan
- Department of Biology, Colgate University, Hamilton, NY 13346, USA
| | - James E Watkins
- Department of Biology, Colgate University, Hamilton, NY 13346, USA
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Zhang SB, Dai Y, Hao GY, Li JW, Fu XW, Zhang JL. Differentiation of water-related traits in terrestrial and epiphytic Cymbidium species. FRONTIERS IN PLANT SCIENCE 2015; 6:260. [PMID: 25954289 PMCID: PMC4406080 DOI: 10.3389/fpls.2015.00260] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 04/02/2015] [Indexed: 05/11/2023]
Abstract
Epiphytes that grow in the canopies of tropical and subtropical forests experience different water regimes when compared with terrestrial plants. However, the differences in adaptive strategies between epiphytic and terrestrial plants with respect to plant water relations remain poorly understood. To understand how water-related traits contrast between epiphytic and terrestrial growth forms within the Cymbidium (Orchidaceae), we assessed leaf anatomy, hydraulics, and physiology of seven terrestrial and 13 epiphytic species using a common garden experiment. Compared with terrestrial species, epiphytic species had higher values for leaf mass per unit area (LMA), leaf thickness (LT), epidermal thickness, saturated water content (SWC) and the time required to dry saturated leaves to 70% relative water content (T70). However, vein density (Dvein), stomatal density (SD), and photosynthetic capacity (Amax) did not differ significantly between the two forms. T70 was positively correlated with LT, LMA, and SWC, and negatively correlated with stomatal index (SI). Amax showed positive correlations with SD and SI, but not with Dvein. Vein density was marginally correlated with SD, and significantly correlated with SI. Overall, epiphytic orchids exhibited substantial ecophysiological differentiations from terrestrial species, with the former type showing trait values indicative of greater drought tolerance and increased water storage capacity. The ability to retain water in the leaves plays a key role in maintaining a water balance in those epiphytes. Therefore, the process of transpiration depends less upon the current substrate water supply and enables epiphytic Cymbidium species to adapt more easily to canopy habitats.
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Affiliation(s)
- Shi-Bao Zhang
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of SciencesKunming, China
- Yunnan Key Laboratory for Wild Plant ResourcesKunming, China
| | - Yan Dai
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of SciencesKunming, China
| | - Guang-You Hao
- State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of SciencesShenyang, China
- The Arnold Arboretum of Harvard UniversityBoston, MA, USA
| | - Jia-Wei Li
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of SciencesKunming, China
| | - Xue-Wei Fu
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of SciencesKunming, China
| | - Jiao-Lin Zhang
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of SciencesKunming, China
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Brodersen C, Jansen S, Choat B, Rico C, Pittermann J. Cavitation Resistance in Seedless Vascular Plants: The Structure and Function of Interconduit Pit Membranes. PLANT PHYSIOLOGY 2014; 165:895-904. [PMID: 24777347 PMCID: PMC4044861 DOI: 10.1104/pp.113.226522] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2013] [Accepted: 04/13/2014] [Indexed: 05/17/2023]
Abstract
Plant water transport occurs through interconnected xylem conduits that are separated by partially digested regions in the cell wall known as pit membranes. These structures have a dual function. Their porous construction facilitates water movement between conduits while limiting the spread of air that may enter the conduits and render them dysfunctional during a drought. Pit membranes have been well studied in woody plants, but very little is known about their function in more ancient lineages such as seedless vascular plants. Here, we examine the relationships between conduit air seeding, pit hydraulic resistance, and pit anatomy in 10 species of ferns (pteridophytes) and two lycophytes. Air seeding pressures ranged from 0.8 ± 0.15 MPa (mean ± sd) in the hydric fern Athyrium filix-femina to 4.9 ± 0.94 MPa in Psilotum nudum, an epiphytic species. Notably, a positive correlation was found between conduit pit area and vulnerability to air seeding, suggesting that the rare-pit hypothesis explains air seeding in early-diverging lineages much as it does in many angiosperms. Pit area resistance was variable but averaged 54.6 MPa s m-1 across all surveyed pteridophytes. End walls contributed 52% to the overall transport resistance, similar to the 56% in angiosperm vessels and 64% in conifer tracheids. Taken together, our data imply that, irrespective of phylogenetic placement, selection acted on transport efficiency in seedless vascular plants and woody plants in equal measure by compensating for shorter conduits in tracheid-bearing plants with more permeable pit membranes.
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Affiliation(s)
- Craig Brodersen
- School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut 06511 (C.B.);Institute for Systematic Botany and Ecology, Ulm University, 89081 Ulm, Germany (S.J.);University of Western Sydney, Hawkesbury Institute for the Environment, Richmond, New South Wales 2753, Australia (B.C.); andDepartment of Ecology and Evolutionary Biology, University of California, Santa Cruz, California 95064 (C.R., J.P.)
| | - Steven Jansen
- School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut 06511 (C.B.);Institute for Systematic Botany and Ecology, Ulm University, 89081 Ulm, Germany (S.J.);University of Western Sydney, Hawkesbury Institute for the Environment, Richmond, New South Wales 2753, Australia (B.C.); andDepartment of Ecology and Evolutionary Biology, University of California, Santa Cruz, California 95064 (C.R., J.P.)
| | - Brendan Choat
- School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut 06511 (C.B.);Institute for Systematic Botany and Ecology, Ulm University, 89081 Ulm, Germany (S.J.);University of Western Sydney, Hawkesbury Institute for the Environment, Richmond, New South Wales 2753, Australia (B.C.); andDepartment of Ecology and Evolutionary Biology, University of California, Santa Cruz, California 95064 (C.R., J.P.)
| | - Christopher Rico
- School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut 06511 (C.B.);Institute for Systematic Botany and Ecology, Ulm University, 89081 Ulm, Germany (S.J.);University of Western Sydney, Hawkesbury Institute for the Environment, Richmond, New South Wales 2753, Australia (B.C.); andDepartment of Ecology and Evolutionary Biology, University of California, Santa Cruz, California 95064 (C.R., J.P.)
| | - Jarmila Pittermann
- School of Forestry and Environmental Studies, Yale University, New Haven, Connecticut 06511 (C.B.);Institute for Systematic Botany and Ecology, Ulm University, 89081 Ulm, Germany (S.J.);University of Western Sydney, Hawkesbury Institute for the Environment, Richmond, New South Wales 2753, Australia (B.C.); andDepartment of Ecology and Evolutionary Biology, University of California, Santa Cruz, California 95064 (C.R., J.P.)
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Zhang SB, Sun M, Cao KF, Hu H, Zhang JL. Leaf photosynthetic rate of tropical ferns is evolutionarily linked to water transport capacity. PLoS One 2014; 9:e84682. [PMID: 24416265 PMCID: PMC3886989 DOI: 10.1371/journal.pone.0084682] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 11/18/2013] [Indexed: 11/22/2022] Open
Abstract
Ferns usually have relatively lower photosynthetic potential than angiosperms. However, it is unclear whether low photosynthetic potential of ferns is linked to leaf water supply. We hypothesized that there is an evolutionary association of leaf water transport capacity with photosynthesis and stomatal density in ferns. In the present study, a series of functional traits relating to leaf anatomy, hydraulics and physiology were assessed in 19 terrestrial and 11 epiphytic ferns in a common garden, and analyzed by a comparative phylogenetics method. Compared with epiphytic ferns, terrestrial ferns had higher vein density (Dvein), stomatal density (SD), stomatal conductance (gs), and photosynthetic capacity (Amax), but lower values for lower epidermal thickness (LET) and leaf thickness (LT). Across species, all traits varied significantly, but only stomatal length (SL) showed strong phylogenetic conservatism. Amax was positively correlated with Dvein and gs with and without phylogenetic corrections. SD correlated positively with Amax, Dvein and gs, with the correlation between SD and Dvein being significant after phylogenetic correction. Leaf water content showed significant correlations with LET, LT, and mesophyll thickness. Our results provide evidence that Amax of the studied ferns is linked to leaf water transport capacity, and there was an evolutionary association between water supply and demand in ferns. These findings add new insights into the evolutionary correlations among traits involving carbon and water economy in ferns.
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Affiliation(s)
- Shi-Bao Zhang
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, China
| | - Mei Sun
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Kun-Fang Cao
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, China
| | - Hong Hu
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Jiao-Lin Zhang
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, China
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