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Ochoa ME, Henry C, John GP, Medeiros CD, Pan R, Scoffoni C, Buckley TN, Sack L. Pinpointing the causal influences of stomatal anatomy and behavior on minimum, operational, and maximum leaf surface conductance. PLANT PHYSIOLOGY 2024; 196:51-66. [PMID: 38775665 DOI: 10.1093/plphys/kiae292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 04/23/2024] [Indexed: 09/03/2024]
Abstract
Leaf surface conductance to water vapor and CO2 across the epidermis (gleaf) strongly determines the rates of gas exchange. Thus, clarifying the drivers of gleaf has important implications for resolving the mechanisms of photosynthetic productivity and leaf and plant responses and tolerance to drought. It is well recognized that gleaf is a function of the conductances of the stomata (gs) and of the epidermis + cuticle (gec). Yet, controversies have arisen around the relative roles of stomatal density (d) and size (s), fractional stomatal opening (α; aperture relative to maximum), and gec in determining gleaf. Resolving the importance of these drivers is critical across the range of leaf surface conductances, from strong stomatal closure under drought (gleaf,min), to typical opening for photosynthesis (gleaf,op), to maximum achievable opening (gleaf,max). We derived equations and analyzed a compiled database of published and measured data for approximately 200 species and genotypes. On average, within and across species, higher gleaf,min was determined 10 times more strongly by α and gec than by d and negligibly by s; higher gleaf,op was determined approximately equally by α (47%) and by stomatal anatomy (45% by d and 8% by s), and negligibly by gec; and higher gleaf,max was determined entirely by d. These findings clarify how diversity in stomatal functioning arises from multiple structural and physiological causes with importance shifting with context. The rising importance of d relative to α, from gleaf,min to gleaf,op, enables even species with low gleaf,min, which can retain leaves through drought, to possess high d and thereby achieve rapid gas exchange in periods of high water availability.
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Affiliation(s)
- Marissa E Ochoa
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA
| | - Christian Henry
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA
| | - Grace P John
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - Camila D Medeiros
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA
| | - Ruihua Pan
- School of Ecology and Environment, Inner Mongolia University, Hohhot, 010021, China
| | - Christine Scoffoni
- Department of Biological Sciences, California State University, Los Angeles, CA 90032, USA
| | - Thomas N Buckley
- Department of Plant Sciences, University of California, Davis, CA 95616, USA
| | - Lawren Sack
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA
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2
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Pichaco J, Manandhar A, McAdam SAM. Mechanical advantage makes stomatal opening speed a function of evaporative demand. PLANT PHYSIOLOGY 2024; 195:370-377. [PMID: 38217870 DOI: 10.1093/plphys/kiae023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 12/20/2023] [Accepted: 12/21/2023] [Indexed: 01/15/2024]
Abstract
Stomatal opening in the light, observed in nearly all vascular land plants, is essential for providing access to atmospheric CO2 for photosynthesis. The speed of stomatal opening in the light is critical for maximizing carbon gain in environments in which light intensity changes, yet we have little understanding of how other environmental signals, particularly evaporative demand driven by vapor pressure deficit (VPD) influences the kinetics of this response. In angiosperms, and some fern species from the family Marsileaceae, a mechanical interaction between the guard cells and the epidermal cells determines the aperture of the pore. Here, we examine whether this mechanical interaction influences the speed of stomatal opening in the light. To test this, we investigated the speed of stomatal opening in response to light across a range of VPDs in seven plant species spanning the evolutionary diversity of guard cell and epidermal cell mechanical interactions. We found that stomatal opening speed is a function of evaporative demand in angiosperm species and Marsilea, which have guard cell and epidermal cell mechanical interactions. Stomatal opening speeds did not change across a range of VPD in species of gymnosperm and fern, which do not have guard cell mechanical interactions with the epidermis. We find that guard cell and epidermal cell mechanical interactions may play a key role in regulating stomatal responsiveness to light. These results provide valuable insight into the adaptive relevance of mechanical advantage.
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Affiliation(s)
- Javier Pichaco
- Irrigation and Crop Ecophysiology Group, Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS, CSIC), Avenida Reina Mercedes 10, 41012 Seville, Spain
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA
| | - Anju Manandhar
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA
| | - Scott A M McAdam
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA
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3
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Binstock BR, Manandhar A, McAdam SAM. Characterizing the breakpoint of stomatal response to vapor pressure deficit in an angiosperm. PLANT PHYSIOLOGY 2024; 194:732-740. [PMID: 37850913 DOI: 10.1093/plphys/kiad560] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 09/21/2023] [Accepted: 10/05/2023] [Indexed: 10/19/2023]
Abstract
Vapor pressure difference between the leaf and atmosphere (VPD) is the most important regulator of daytime transpiration, yet the mechanism driving stomatal responses to an increase in VPD in angiosperms remains unresolved. Here, we sought to characterize the mechanism driving stomatal closure at high VPD in an angiosperm species, particularly testing whether abscisic acid (ABA) biosynthesis could explain the observation of a trigger point for stomatal sensitivity to an increase in VPD. We tracked leaf gas exchange and modeled leaf water potential (Ψl) in leaves exposed to a range of step-increases in VPD in the herbaceous species Senecio minimus Poir. (Asteraceae). We found that mild increases in VPD in this species did not induce stomatal closure because modeled Ψl did not decline below a threshold close to turgor loss point (Ψtlp), but when leaves were exposed to a large increase in VPD, stomata closed as modeled Ψl declined below Ψtlp. Leaf ABA levels were higher in leaves exposed to a step-increase in VPD that caused Ψl to transiently decline below Ψtlp and in which stomata closed compared with leaves in which stomata did not close. We conclude that the stomata of S. minimus are insensitive to VPD until Ψl declines to a threshold that triggers the biosynthesis of ABA and that this mechanism might be common to angiosperms.
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Affiliation(s)
- Benjamin R Binstock
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA
| | - Anju Manandhar
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA
| | - Scott A M McAdam
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA
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4
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Zekri MA, Leimhofer C, Drexler N, Lang I. A rapid freezing method to determine tissue layer thickness in drought-stressed leaves. J Microsc 2024. [PMID: 38282132 DOI: 10.1111/jmi.13272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 01/16/2024] [Accepted: 01/22/2024] [Indexed: 01/30/2024]
Abstract
Plants have been affected by water stress ever since they settled on dry land. In severe and persisting drought, plant leaves are wilting. However, a documentation at the anatomical level of the minute changes that occur before wilting is challenging. On the other hand, understanding the anatomical alteration in plant leaves with respect to water stress provides a stronger basis to study molecular and submolecular processes through which plants enhance drought tolerance. In this work, we applied an affordable method to visualise mesophyll layers of Arabidopsis thaliana cell lines without preparation steps that would alter the volume of the cells. We rapidly plunge-froze the leaves in liquid nitrogen, cut them while in the N2 bath, and immediately imaged the mesophyll cross sections in a scanning electron microscope. We applied a reduction of watering from 60 to 40 to 20 mL per day and investigated two time points, 7 and 12 days, respectively. Interestingly, the overall thickness of leaves increased in water stress conditions. Our results showed that the palisade and spongy layers behaved differently under varying watering regimes. Moreover, the results showed that this method can be used to image leaf sections after drought stress without the risk of artefacts or swelling caused by contact to liquids as during chemical fixation.
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Affiliation(s)
- Maryam Alsadat Zekri
- Faculty of Life Sciences, Department of Functional and Evolutionary Ecology, University of Vienna, Vienna, Austria
| | - Carina Leimhofer
- Faculty of Life Sciences, Department of Functional and Evolutionary Ecology, University of Vienna, Vienna, Austria
| | | | - Ingeborg Lang
- Faculty of Life Sciences, Department of Functional and Evolutionary Ecology, University of Vienna, Vienna, Austria
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5
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Zhang K, Xue M, Qin F, He Y, Zhou Y. Natural polymorphisms in ZmIRX15A affect water-use efficiency by modulating stomatal density in maize. PLANT BIOTECHNOLOGY JOURNAL 2023; 21:2560-2573. [PMID: 37572352 PMCID: PMC10651153 DOI: 10.1111/pbi.14153] [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: 12/01/2022] [Revised: 05/11/2023] [Accepted: 07/31/2023] [Indexed: 08/14/2023]
Abstract
Stomatal density (SD) is closely related to crop drought resistance. Understanding the genetic basis for natural variation in SD may facilitate efforts to improve water-use efficiency. Here, we report a genome-wide association study for SD in maize seedlings, which identified 18 genetic variants that could be resolved to seven candidate genes. A 3-bp insertion variant (InDel1089) in the last exon of Zea mays (Zm) IRX15A (Irregular xylem 15A) had the most significant association with SD and modulated the translation of ZmIRX15A mRNA by affecting its secondary structure. Dysfunction of ZmIRX15A increased SD, leading to an increase in the transpiration rate and CO2 assimilation efficiency. ZmIRX15A encodes a xylan deposition enzyme and its disruption significantly decreased xylan abundance in secondary cell wall composition. Transcriptome analysis revealed a substantial alteration of the expression of genes involved in stomatal complex morphogenesis and drought response in the loss-of-function of ZmIRX15A mutant. Overall, our study provides important genetic insights into the natural variation of leaf SD in maize, and the identified loci or genes can serve as direct targets for enhancing drought resistance in molecular-assisted maize breeding.
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Affiliation(s)
- Kun Zhang
- State Key Laboratory of Plant Physiology and BiochemistryEngineering Research Center of Plant Growth RegulatorCollege of Agronomy and BiotechnologyChina Agricultural UniversityBeijingChina
| | - Ming Xue
- Jiangsu Key Laboratory of Crop Genetics and PhysiologyCo‐Innovation Center for Modern Production Technology of Grain CropsKey Laboratory of Plant Functional Genomics of the Ministry of EducationYangzhou UniversityYangzhouChina
| | - Feng Qin
- State Key Laboratory of Plant Physiology and BiochemistryCollege of Biological SciencesChina Agricultural UniversityBeijingChina
| | - Yan He
- National Maize Improvement Center of ChinaCollege of Agronomy and BiotechnologyChina Agricultural UniversityBeijingChina
| | - Yuyi Zhou
- State Key Laboratory of Plant Physiology and BiochemistryEngineering Research Center of Plant Growth RegulatorCollege of Agronomy and BiotechnologyChina Agricultural UniversityBeijingChina
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Poudyal D, Joshi BK, Zhou R, Ottosen CO, Dahal KC. Evaluating the physiological responses and identifying stress tolerance of Akabare chili landraces to individual and combined drought and heat stresses. AOB PLANTS 2023; 15:plad083. [PMID: 38106642 PMCID: PMC10721449 DOI: 10.1093/aobpla/plad083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 11/28/2023] [Indexed: 12/19/2023]
Abstract
Abstract. Akabare chili (Capsicum annuum) contributes to Nepalese rural livelihoods but suffers from low productivity due to various abiotic stresses including drought and heat. This study aimed to assess the physiological responses of Akabare chili landraces to heat and drought stress, individually and together, and to identify stress-tolerant genotypes in the early vegetative stage. Selected eight Akabare chili landraces and chili variety 'Jwala' were subjected to control (30/22 °C day/night) and heat stress (40/32 °C) conditions with irrigation, and drought stress (30/22 °C) and combined drought-heat stress conditions without irrigation for 7 days, followed by a 5-day recovery under control condition. Stress-tolerant landraces showed better performance compared to sensitive ones in terms of efficacy of PS II (Fv/Fm), transpiration rate (E), net photosynthetic rate (PN), stomatal conductance (gs), leaf temperature depression, water use efficiency (WUE) and the ratio of stomata pore area to stomata area under stress conditions, resulting in improved biomass. Although all genotypes performed statistically similar under control conditions, their responses Fv/Fm, PN, E, gs and WUE were significantly reduced under thermal stress, further reduced under drought stress, and severely declined under the combination of both. Total biomass exhibited a 57.48 % reduction due to combined stress, followed by drought (37.8 %) and heat (21.4 %) compared to the control. Among the landraces, C44 showed the most significant gain in biomass (35 %), followed by DKT77 (33.48 %), while the lowest gain percentage was observed for C64C and PPR77 during the recovery phase (29 %). The tolerant landraces also showed a higher percentage of leaf cooling, chlorophyll content and leaf relative water content with fewer stomata but broader openings of pores. The study identifies potential stress-tolerant Akabare chili landraces and discusses the stress-tolerant physiological mechanisms to develop resilient crop varieties in changing climates.
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Affiliation(s)
- Damodar Poudyal
- Postgraduate Program, Institute of Agriculture and Animal Science, Tribhuvan University, Kirtipur-10, 44618 Kathmandu, Nepal
| | - Bal Krishna Joshi
- National Agriculture Genetic Resource Center, Nepal Agriculture Research Council, Khumaltar, 44700 Lalitpur, Nepal
| | - Rong Zhou
- College of Horticulture, Nanjing Agriculture University, Weigang No.1, 210095 Nanjing, China
| | - Carl-Otto Ottosen
- Department of Food Science, Aarhus University, Agro Food Park 48, 8200 Aarhus N, Denmark
| | - Kishor Chandra Dahal
- Postgraduate Program, Institute of Agriculture and Animal Science, Tribhuvan University, Kirtipur-10, 44618 Kathmandu, Nepal
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Aros-Mualin D, Guadagno CR, Silvestro D, Kessler M. Light, rather than circadian rhythm, regulates gas exchange in ferns and lycophytes. PLANT PHYSIOLOGY 2023; 191:1634-1647. [PMID: 36691320 PMCID: PMC10022864 DOI: 10.1093/plphys/kiad036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 12/13/2022] [Indexed: 06/17/2023]
Abstract
Circadian regulation plays a vital role in optimizing plant responses to the environment. However, while circadian regulation has been extensively studied in angiosperms, very little is known for lycophytes and ferns, leaving a gap in our understanding of the evolution of circadian rhythms across the plant kingdom. Here, we investigated circadian regulation in gas exchange through stomatal conductance and photosynthetic efficiency in a phylogenetically broad panel of 21 species of lycophytes and ferns over a 46 h period under constant light and a selected few under more natural conditions with day-night cycles. No rhythm was detected under constant light for either lycophytes or ferns, except for two semi-aquatic species of the family Marsileaceae (Marsilea azorica and Regnellidium diphyllum), which showed rhythms in stomatal conductance. Furthermore, these results indicated the presence of a light-driven stomatal control for ferns and lycophytes, with a possible passive fine-tuning through leaf water status adjustments. These findings support previous evidence for the fundamentally different regulation of gas exchange in lycophytes and ferns compared to angiosperms, and they suggest the presence of alternative stomatal regulations in Marsileaceae, an aquatic family already well known for numerous other distinctive physiological traits. Overall, our study provides evidence for heterogeneous circadian regulation across plant lineages, highlighting the importance of broad taxonomic scope in comparative plant physiology studies.
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Affiliation(s)
| | | | - Daniele Silvestro
- Department of Biology, University of Fribourg, Fribourg 1700, Switzerland
- Department of Biological and Environmental Sciences and Global Gothenburg Biodiversity Centre, University of Gothenburg, Gothenburg SE-405 30, Sweden
- Swiss Institute of Bioinformatics, Fribourg 1700, Switzerland
| | - Michael Kessler
- Department of Systematics and Evolutionary Botany, University of Zurich, Zurich 8008, Switzerland
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Haworth M, Marino G, Materassi A, Raschi A, Scutt CP, Centritto M. The functional significance of the stomatal size to density relationship: Interaction with atmospheric [CO 2] and role in plant physiological behaviour. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 863:160908. [PMID: 36535478 DOI: 10.1016/j.scitotenv.2022.160908] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 12/08/2022] [Accepted: 12/09/2022] [Indexed: 06/17/2023]
Abstract
The limits for stomatal conductance are set by stomatal size (SS) and density (SD). An inverse relationship between SS and SD has been observed in fossil and living plants. This has led to hypotheses proposing that the ratio of SS to SD influences the diffusion pathway for CO2 and degree of physiological stomatal control. However, conclusive evidence supportive of a functional role of the SS-SD relationship is not evident, and patterns in SS-SD may simply reflect geometric constraints in stomatal spacing over a leaf surface. We examine published and new data to investigate the potential functional significance of the relationship between SS and SD to atmospheric [CO2] in multiple generation adaptive responses and short-term acclamatory adjustment of stomatal morphology. Consistent patterns in SS and SD were not evident in fossil and living plants adapted to high [CO2] over many generations. However, evolutionary adaptation to [CO2] strongly affected SS and SD responses to elevated [CO2], with plants adapted to the 'low' [CO2] of the past 10 million years (Myr) showing adjustment of SS-SD, while members of the same species adapted to 'high' [CO2] showed no response. This may suggest that SS and SD responses to future [CO2] will likely constrain the stimulatory effect of 'CO2-fertilisation' on photosynthesis. Angiosperms generally possessed higher densities of smaller stomata that corresponded to a greater degree of physiological stomatal control consistent with selective pressures induced by declining [CO2] over the past 90 Myr. Atmospheric [CO2] has likely shaped stomatal size and density relationships alongside the interaction with stomatal physiological behaviour. The rate and predicted extent of future increases in [CO2] will have profound impacts on the selective pressures shaping SS and SD. Understanding the trade-offs involved in SS-SD and the interaction with [CO2], will be central to the development of more productive climate resilient crops.
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Affiliation(s)
- Matthew Haworth
- Institute for Sustainable Plant Protection, National Research Council of Italy (CNR-IPSP), Via Madonna del Piano 10 Sesto Fiorentino, 50019 Firenze, Italy.
| | - Giovanni Marino
- Institute for Sustainable Plant Protection, National Research Council of Italy (CNR-IPSP), Via Madonna del Piano 10 Sesto Fiorentino, 50019 Firenze, Italy
| | - Alessandro Materassi
- The Institute of BioEconomy, National Research Council of Italy (CNR-IBE), Via Giovanni Caproni 8, 50145 Firenze, Italy
| | - Antonio Raschi
- The Institute of BioEconomy, National Research Council of Italy (CNR-IBE), Via Giovanni Caproni 8, 50145 Firenze, Italy
| | - Charles P Scutt
- Laboratoire de Reproduction et Développement des Plantes, UMR5667, CNRS, INRA, Université de Lyon, Ecole Normale Supérieure de Lyon, Lyon Cedex 07, France
| | - Mauro Centritto
- Institute for Sustainable Plant Protection, National Research Council of Italy (CNR-IPSP), Via Madonna del Piano 10 Sesto Fiorentino, 50019 Firenze, Italy
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Suissa JS, Agbleke AA, Friedman WE. A bump in the node: The hydraulic implications of rhizomatous growth. AMERICAN JOURNAL OF BOTANY 2023; 110:e16105. [PMID: 36401563 DOI: 10.1002/ajb2.16105] [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: 03/04/2022] [Revised: 11/06/2022] [Accepted: 11/08/2022] [Indexed: 06/16/2023]
Abstract
PREMISE Rhizomatous growth characterizes numerous taxa among vascular plants. While abundant information exists on nutrient sharing and demography, the question of how these metameric organisms move water through their bodies remains largely unstudied. Moreover, we lack an understanding of the evolutionary implications of rhizomatous growth across vascular plants. Here, we examined these questions by investigating how rhizomatous growth and vascular construction affect whole-plant hydraulic function. METHODS In five terrestrial fern species with diverse vascular construction, we used microcomputed tomography and bright-field microscopy to examine vascular construction across nodes along the rhizome. These data were integrated with measurements of leaf stomatal conductance under rooted and uprooted conditions to relate vascular patterning and hydraulic architecture to leaf water status. RESULTS Similar to phytomers of woody seed plants, nodal regions in rhizomatous ferns are areas of hydraulic resistance. While water is shared along the rhizomes of these investigated species, hydraulic conductivity drops at nodes and stomatal conductance declines when nodes were locally uprooted. Together, our data suggest that nodes are chokepoints in axial water movement along the rhizome. CONCLUSIONS Nodal chokepoints decrease hydraulic integration between phytomers. At the same time, chokepoints may act as "safety valves", hydraulically localizing each phytomer-potentially decreasing embolism and pathogen spread. This suggests a potential trade-off in the principal construction of the fern rhizome. Moreover, we propose that shoot-borne roots (homorhizy) and the prostrate habit of rhizomatous ferns decrease the hydraulic and structural burdens that upright plants typically incur. The absence of these hydraulic and structural demands may be one reason ferns (and many rhizomatous plants) lack, or have minimally developed, secondary xylem.
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Affiliation(s)
- Jacob S Suissa
- The Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- The Arnold Arboretum of Harvard University, Boston, MA, USA
| | | | - William E Friedman
- The Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
- The Arnold Arboretum of Harvard University, Boston, MA, USA
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Chen Y, Zhu W, Yan T, Chen D, Jiang L, Chen ZH, Wu D. Stomatal morphological variation contributes to global ecological adaptation and diversification of Brassica napus. PLANTA 2022; 256:64. [PMID: 36029339 DOI: 10.1007/s00425-022-03982-4] [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: 06/29/2022] [Accepted: 08/22/2022] [Indexed: 06/15/2023]
Abstract
Stomatal density and guard cell length of 274 global core germplasms of rapeseed reveal that the stomatal morphological variation contributes to global ecological adaptation and diversification of Brassica napus. Stomata are microscopic structures of plants for the regulation of CO2 assimilation and transpiration. Stomatal morphology has changed substantially in the adaptation to the external environment during land plant evolution. Brassica napus is a major crop to produce oil, livestock feed and biofuel in the world. However, there are few studies on the regulatory genes controlling stomatal development and their interaction with environmental factors as well as the genetic mechanism of adaptive variation in B. napus. Here, we characterized stomatal density (SD) and guard cell length (GL) of 274 global core germplasms at seedling stage. It was found that among the significant phenotypic variation, European germplasms are mostly winter rapeseed with high stomatal density and small guard cell length. However, the germplasms from Asia (especially China) are semi-winter rapeseed, which is characterized by low stomatal density and large guard cell length. Through selective sweep analysis and homology comparison, we identified several candidate genes related to stomatal density and guard cell length, including Epidermal Patterning Factor2 (EPF2; BnaA09g23140D), Epidermal Patterning Factor Like4 (EPFL4; BnaC01g22890D) and Suppressor of LLP1 (SOL1 BnaC01g22810D). Haplotype and phylogenetic analysis showed that natural variation in EPF2, EPFL4 and SOL1 is closely associated with the winter, spring, and semi-winter rapeseed ecotypes. In summary, this study demonstrated for the first time the relation between stomatal phenotypic variation and ecological adaptation in rapeseed, which is useful for future molecular breeding of rapeseed in the context of evolution and domestication of key stomatal traits and global climate change.
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Affiliation(s)
- Yeke Chen
- Department of Agronomy, Key Laboratory of Crop Germplasm Resource of Zhejiang Province, Zhejiang University, Hangzhou, 310058, China
| | - Weizhuo Zhu
- Department of Agronomy, Key Laboratory of Crop Germplasm Resource of Zhejiang Province, Zhejiang University, Hangzhou, 310058, China
| | - Tao Yan
- College of Agronomy, Hunan Agricultural University, Changsha, 410128, China
| | - Danyi Chen
- Department of Agronomy, Key Laboratory of Crop Germplasm Resource of Zhejiang Province, Zhejiang University, Hangzhou, 310058, China
| | - Lixi Jiang
- Department of Agronomy, Key Laboratory of Crop Germplasm Resource of Zhejiang Province, Zhejiang University, Hangzhou, 310058, China
| | - Zhong-Hua Chen
- School of Science, Western Sydney University, Penrith, NSW, Australia.
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia.
| | - Dezhi Wu
- Department of Agronomy, Key Laboratory of Crop Germplasm Resource of Zhejiang Province, Zhejiang University, Hangzhou, 310058, China.
- College of Agronomy, Hunan Agricultural University, Changsha, 410128, China.
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11
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Xie J, Wang Z, Li Y. Stomatal opening ratio mediates trait coordinating network adaptation to environmental gradients. THE NEW PHYTOLOGIST 2022; 235:907-922. [PMID: 35491493 DOI: 10.1111/nph.18189] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 04/22/2022] [Indexed: 06/14/2023]
Abstract
A trait coordination network is constructed through intercorrelations of functional traits, which reflect trait-based adaptive strategies. However, little is known about how these networks change across spatial scales, and what drivers and mechanisms mediate this change. This study bridges that gap by integrating functional traits related to plant carbon gain and water economy into the coordination network of Siberian elm (Ulmus pumila), a eurybiont that survives along a 3800 km environmental gradient from humid forest to arid desert. Our results demonstrated that both stomatal density and stomatal size reached a physiological threshold at which adjustments in these traits were not sufficient to cope with the increased environmental stress. Network analysis further revealed that the mechanism for overcoming this threshold, the stomatal opening ratio, gratio , was represented by the highest values for centrality across different spatial scales, and therefore mediated the changes in the trait coordination network along environmental gradients. The mediating roles manifested as creating the highest maximum theoretical stomatal conductance (gsmax ) but lowest possible gratio for pathogen defense in humid regions, while maintaining the gratio 'sweet spot' (c. 20% in this region) for highest water use efficiency in semihumid regions, and having the lowest gsmax and highest gratio for gas exchange and leaf cooling in arid regions. These results suggested that the stomatal traits related to control of stomatal movement play fundamental roles in balancing gas exchange, leaf cooling, embolism resistance and pathogen defense. These insights will allow more accurate model parameterization for different regions, and therefore better predictions of species' responses to global change.
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Affiliation(s)
- Jiangbo Xie
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou, 311300, China
| | - Zhongyuan Wang
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou, 311300, China
| | - Yan Li
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou, 311300, China
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Marek S, Tomaszewski D, Żytkowiak R, Jasińska A, Zadworny M, Boratyńska K, Dering M, Danusevičius D, Oleksyn J, Wyka TP. Stomatal density in Pinus sylvestris as an indicator of temperature rather than CO 2 : Evidence from a pan-European transect. PLANT, CELL & ENVIRONMENT 2022; 45:121-132. [PMID: 34748220 DOI: 10.1111/pce.14220] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 10/13/2021] [Accepted: 10/28/2021] [Indexed: 05/15/2023]
Abstract
The commonly observed negative relationship between stomatal density (SD) and atmospheric CO2 has led to SD being proposed as an indicator of atmospheric CO2 concentration. The use of SD as a proxy for CO2 , however, has been hampered by an insufficient understanding of the intraspecific variation of this trait. We hypothesized that SD in Pinus sylvestris, a widely distributed conifer, varies geographically and that this variation is determined by major climatic variables. By sampling needles from naturally growing trees along a latitudinal range of 32.25°, equivalent to 13.7°C gradient of mean annual temperature (MAT) across Europe, we found that SD decreased from the warmest southern sites to the coldest sites in the north at a rate of 4 stomata per mm2 for each 1°C, with MAT explaining 44% of the variation. Additionally, samples from a provenance trial exhibited a positive relationship between SD and the MAT of the original localities, suggesting that high SD is an adaptation to warm temperature. Our study revealed one of the strongest intraspecific relationships between SD and climate in any woody species, supporting the utility of SD as a temperature, rather than direct CO2 , proxy. In addition, our results predict the response of SD to climate warming.
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Affiliation(s)
- Sławomir Marek
- Institute of Dendrology, Polish Academy of Sciences, Kórnik, Poland
| | | | - Roma Żytkowiak
- Institute of Dendrology, Polish Academy of Sciences, Kórnik, Poland
| | - Anna Jasińska
- Institute of Dendrology, Polish Academy of Sciences, Kórnik, Poland
| | - Marcin Zadworny
- Institute of Dendrology, Polish Academy of Sciences, Kórnik, Poland
| | | | | | - Darius Danusevičius
- Faculty of Forest Science and Ecology, Aleksandras Stulginskis University, Akademija, Kaunas, Lithuania
| | - Jacek Oleksyn
- Institute of Dendrology, Polish Academy of Sciences, Kórnik, Poland
| | - Tomasz P Wyka
- Faculty of Biology, Adam Mickiewicz University, Poznań, Poland
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