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Yuan Z, Ni X, Chen C, Zhang S, Chen X, Yang Z, Li C. Effects of different water conditions on the biomass, root morphology and aerenchyma formation in bermudagrass (Cynodon dactylon (L.) Pers). BMC PLANT BIOLOGY 2022; 22:266. [PMID: 35637438 PMCID: PMC9150380 DOI: 10.1186/s12870-022-03653-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 05/18/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND The bermudagrass (Cynodon dactylon (L.) Pers) roots responded differently in terms of morphological and anatomical characteristics under diverse submergence conditions, and they developed aerenchyma under non-flooding condition. In order to understand these mechanisms, bermudagrass cuttings were used as experimental material to examine their biomass, root morphology, and aerenchyma formation under three different water treatments, including control (CK), shallow submergence (SS), and deep submergence (DS). RESULTS The total root length, root volume, root surface area, and biomass of bermudagrass were largest in CK, followed by SS and DS. However, the average root diameter was greater in each of DS and SS than that in CK. Root aerenchyma formation was observed in CK, and submergence boosted the aerenchyma formation and the root cavity rate. Furthermore, our study found that the process of aerenchyma formation began with the increase of cell volume and cell separation to form a narrow space, and these cells gradually died to form matured aerenchyma cavity, which belongs to schizo-lysigenous aerenchyma. Meanwhile, typical biomarkers of programmed cell death were also observed. CONCLUSION Overall, these results suggested that submergence inhibited the accumulation of biomass and root growth, but facilitated aerenchyma formation by increasing root diameter.
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Affiliation(s)
- Zhongxun Yuan
- Key Laboratory of Eco-Environments in the Three Gorges Reservoir Region (Ministry of Education), Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, College of Life Sciences, Southwest University, Chongqing, 400715, China
- State Cultivation Base of Eco-Agriculture for Southwest Mountainous Land, Southwest University, Chongqing, 400715, China
| | - Xilu Ni
- Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration of North-Western China, Key Lab for Restoration and Reconstruction of Degraded Ecosystem in North-Western China (Ministry of Education), Ningxia University, Yinchuan, 750021, China
| | - Chunhua Chen
- Key Laboratory of Eco-Environments in the Three Gorges Reservoir Region (Ministry of Education), Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, College of Life Sciences, Southwest University, Chongqing, 400715, China
- State Cultivation Base of Eco-Agriculture for Southwest Mountainous Land, Southwest University, Chongqing, 400715, China
| | - Songlin Zhang
- Key Laboratory of Reservoir Aquatic Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing, 400714, China
| | - Xuemei Chen
- Key Laboratory of Eco-Environments in the Three Gorges Reservoir Region (Ministry of Education), Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, College of Life Sciences, Southwest University, Chongqing, 400715, China
- State Cultivation Base of Eco-Agriculture for Southwest Mountainous Land, Southwest University, Chongqing, 400715, China
| | - Zhihua Yang
- Key Laboratory of Eco-Environments in the Three Gorges Reservoir Region (Ministry of Education), Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, College of Life Sciences, Southwest University, Chongqing, 400715, China
- State Cultivation Base of Eco-Agriculture for Southwest Mountainous Land, Southwest University, Chongqing, 400715, China
| | - Changxiao Li
- Key Laboratory of Eco-Environments in the Three Gorges Reservoir Region (Ministry of Education), Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, College of Life Sciences, Southwest University, Chongqing, 400715, China.
- State Cultivation Base of Eco-Agriculture for Southwest Mountainous Land, Southwest University, Chongqing, 400715, China.
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2
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Naidoo G. Waterlogging tolerance of the common reeds
Phragmites mauritianus
and
P. australis. Afr J Ecol 2021. [DOI: 10.1111/aje.12884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Gonasageran Naidoo
- University of KwaZulu‐NatalSchool of Life Sciences Westville South Africa
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3
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Kirk GJ, Boghi A, Affholder M, Keyes SD, Heppell J, Roose T. Soil carbon dioxide venting through rice roots. PLANT, CELL & ENVIRONMENT 2019; 42:3197-3207. [PMID: 31378945 PMCID: PMC6972674 DOI: 10.1111/pce.13638] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 07/29/2019] [Accepted: 07/31/2019] [Indexed: 05/12/2023]
Abstract
The growth of rice in submerged soils depends on its ability to form continuous gas channels-aerenchyma-through which oxygen (O2 ) diffuses from the shoots to aerate the roots. Less well understood is the extent to which aerenchyma permits venting of respiratory carbon dioxide (CO2 ) in the opposite direction. Large, potentially toxic concentrations of dissolved CO2 develop in submerged rice soils. We show using X-ray computed tomography and image-based mathematical modelling that CO2 venting through rice roots is far greater than thought hitherto. We found rates of venting equivalent to a third of the daily CO2 fixation in photosynthesis. Without this venting through the roots, the concentrations of CO2 and associated bicarbonate (HCO3- ) in root cells would have been well above levels known to be toxic to roots. Removal of CO2 and hence carbonic acid (H2 CO3 ) from the soil was sufficient to increase the pH in the rhizosphere close to the roots by 0.7 units, which is sufficient to solubilize or immobilize various nutrients and toxicants. A sensitivity analysis of the model showed that such changes are expected for a wide range of plant and soil conditions.
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Affiliation(s)
- Guy J.D. Kirk
- School of Water, Energy and EnvironmentCranfield UniversityCranfieldUK
| | - Andrea Boghi
- School of Water, Energy and EnvironmentCranfield UniversityCranfieldUK
- Faculty of Engineering and EnvironmentUniversity of SouthamptonSouthamptonUK
| | | | - Samuel D. Keyes
- Faculty of Engineering and EnvironmentUniversity of SouthamptonSouthamptonUK
| | - James Heppell
- Faculty of Engineering and EnvironmentUniversity of SouthamptonSouthamptonUK
| | - Tiina Roose
- Faculty of Engineering and EnvironmentUniversity of SouthamptonSouthamptonUK
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4
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Mohammed U, Caine RS, Atkinson JA, Harrison EL, Wells D, Chater CC, Gray JE, Swarup R, Murchie EH. Rice plants overexpressing OsEPF1 show reduced stomatal density and increased root cortical aerenchyma formation. Sci Rep 2019; 9:5584. [PMID: 30944383 PMCID: PMC6447545 DOI: 10.1038/s41598-019-41922-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 03/19/2019] [Indexed: 01/07/2023] Open
Abstract
Stomata are adjustable pores in the aerial epidermis of plants. The role of stomata is usually described in terms of the trade-off between CO2 uptake and water loss. Little consideration has been given to their interaction with below-ground development or diffusion of other gases. We overexpressed the rice EPIDERMAL PATTERNING FACTOR1 (OsEPF1) to produce rice plants with reduced stomatal densities, resulting in lowered leaf stomatal conductance and enhanced water use efficiency. Surprisingly, we found that root cortical aerenchyma (RCA) is formed constitutively in OsEPF1OE lines regardless of tissue age and position. Aerenchyma is tissue containing air-spaces that can develop in the plant root during stressful conditions, e.g. oxygen deficiency when it functions to increase O2 diffusion from shoot to root. The relationship with stomata is unknown. We conclude that RCA development and stomatal development are linked by two possible mechanisms: first that reduced stomatal conductance inhibits the diffusion of oxygen to the root, creating an oxygen deficit and stimulating the formation of RCA, second that an unknown EPF signalling pathway may be involved. Our observations have fundamental implications for the understanding of whole plant gas diffusion and root-to-shoot signalling events.
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Affiliation(s)
- U. Mohammed
- 0000 0004 1936 8868grid.4563.4Division of Plant and Crop Science, School of Biosciences, University of Nottingham, Sutton Bonington campus, LE12 5RD Nottingham, UK
| | - R. S. Caine
- 0000 0004 1936 9262grid.11835.3eDepartment of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, S10 2TN Sheffield, UK
| | - J. A. Atkinson
- 0000 0004 1936 8868grid.4563.4Division of Plant and Crop Science, School of Biosciences, University of Nottingham, Sutton Bonington campus, LE12 5RD Nottingham, UK
| | - E. L. Harrison
- 0000 0004 1936 9262grid.11835.3eDepartment of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, S10 2TN Sheffield, UK
| | - D. Wells
- 0000 0004 1936 8868grid.4563.4Division of Plant and Crop Science, School of Biosciences, University of Nottingham, Sutton Bonington campus, LE12 5RD Nottingham, UK
| | - C. C. Chater
- 0000 0004 1936 9262grid.11835.3eDepartment of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, S10 2TN Sheffield, UK
| | - J. E. Gray
- 0000 0004 1936 9262grid.11835.3eDepartment of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, S10 2TN Sheffield, UK
| | - R. Swarup
- 0000 0004 1936 8868grid.4563.4Division of Plant and Crop Science, School of Biosciences, University of Nottingham, Sutton Bonington campus, LE12 5RD Nottingham, UK
| | - E. H. Murchie
- 0000 0004 1936 8868grid.4563.4Division of Plant and Crop Science, School of Biosciences, University of Nottingham, Sutton Bonington campus, LE12 5RD Nottingham, UK
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5
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Males J. Concerted anatomical change associated with crassulacean acid metabolism in the Bromeliaceae. FUNCTIONAL PLANT BIOLOGY : FPB 2018; 45:681-695. [PMID: 32291044 DOI: 10.1071/fp17071] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 01/05/2018] [Indexed: 06/11/2023]
Abstract
Crassulacean acid metabolism (CAM) is a celebrated example of convergent evolution in plant ecophysiology. However, many unanswered questions surround the relationships among CAM, anatomy and morphology during evolutionary transitions in photosynthetic pathway. An excellent group in which to explore these issues is the Bromeliaceae, a diverse monocot family from the Neotropics in which CAM has evolved multiple times. Progress in the resolution of phylogenetic relationships among the bromeliads is opening new and exciting opportunities to investigate how evolutionary changes in leaf structure has tracked, or perhaps preceded, photosynthetic innovation. This paper presents an analysis of variation in leaf anatomical parameters across 163C3 and CAM bromeliad species, demonstrating a clear divergence in the fundamental aspects of leaf structure in association with the photosynthetic pathway. Most strikingly, the mean volume of chlorenchyma cells of CAM species is 22 times higher than that of C3 species. In two bromeliad subfamilies (Pitcairnioideae and Tillandsioideae), independent transitions from C3 to CAM are associated with increased cell succulence, whereas evolutionary trends in tissue thickness and leaf air space content differ between CAM origins. Overall, leaf anatomy is clearly and strongly coupled with the photosynthetic pathway in the Bromeliaceae, where the independent origins of CAM have involved significant anatomical restructuring.
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Affiliation(s)
- Jamie Males
- Department of Plant Sciences, University of Cambridge, Cambridge, UK. Email
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6
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The Structure and Flexural Properties of Typha Leaves. Appl Bionics Biomech 2017; 2017:1249870. [PMID: 29123373 PMCID: PMC5662842 DOI: 10.1155/2017/1249870] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Accepted: 08/27/2017] [Indexed: 11/26/2022] Open
Abstract
The Typha leaf has a structure of lightweight cantilever beam, exhibiting excellent mechanical properties with low density. Especially, the leaf blade evolved high strength and low density with high porosity. In this paper, the structure of Typha leaf was characterized by microcomputed tomography (Micro-CT) and scanning electron microscopy (SEM), and the relationship with flexural properties was analyzed. The three-point bending test was performed on leaves to examine flexural properties, which indicated that the flexural properties vary from the base to the apex in gradient. The cross-sectional geometry shape of the leaf blade presented a strong influence on the optimized flexural stiffness. The load carrying capacity of the leaf depended on the development level of the epidermal tissue, the vascular bundle, the mechanical tissue, and the geometric properties. The investigation can be the basis for lightweight structure design and the application in the bionic engineering field.
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7
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Liu J, Zhang Z, Yu Z, Liang Y, Li X, Ren L. Experimental study and numerical simulation on the structural and mechanical properties of Typha leaves through multimodal microscopy approaches. Micron 2017; 104:37-44. [PMID: 29073496 DOI: 10.1016/j.micron.2017.10.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 10/11/2017] [Accepted: 10/11/2017] [Indexed: 11/24/2022]
Abstract
The Typha leaf, with special multi-level structure, low density and excellent mechanical properties, is an ideal bionic prototype utilized for lightweight design. In order to further study the relationship between the structure and mechanical properties, the three-dimensional macroscopic morphology of Typha leaves was characterized by micro computed tomography (Micro-CT) and its internal microstructure was observed by scanning electron microscopy (SEM). The combination of experimental and computational research was carried out in this paper, to reveal and verify the effect of multi-level structure on the mechanical properties. A universal testing machine and a self-developed mechanical testing apparatus with high precision and low load were used to measure the mechanical properties of the axial compression and lateral bending of the leaves, respectively. Three models with different internal structures were established based on the above-mentioned three-dimensional morphologies. The result demonstrated that the structure of partitions and diaphragms within the Typha leaf could form a reinforcement ribs structure which could provide multiple load paths and make the process of compression and bending difficult. The further nonlinear finite element analysis through LS-DYNA proved that internal structure could improve the ability of the models to resist compression and deformation. The investigation can be the reference for lightweight thin-walled structure design and inspire the application of the bionic structural materials.
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Affiliation(s)
- Jingjing Liu
- The Key Laboratory of Engineering Bionic (Ministry of Education, China) and the College of Biological and Agricultural Engineering, Jilin University, 5988 Renmin Street, Changchun, 130025, China
| | - Zhihui Zhang
- The Key Laboratory of Engineering Bionic (Ministry of Education, China) and the College of Biological and Agricultural Engineering, Jilin University, 5988 Renmin Street, Changchun, 130025, China; State Key Laboratory of Automotive Simulation and Control, Jilin University, 5988 Renmin Street, Changchun, 130025, China.
| | - Zhenglei Yu
- The Key Laboratory of Engineering Bionic (Ministry of Education, China) and the College of Biological and Agricultural Engineering, Jilin University, 5988 Renmin Street, Changchun, 130025, China.
| | - Yunhong Liang
- The Key Laboratory of Engineering Bionic (Ministry of Education, China) and the College of Biological and Agricultural Engineering, Jilin University, 5988 Renmin Street, Changchun, 130025, China; State Key Laboratory of Automotive Simulation and Control, Jilin University, 5988 Renmin Street, Changchun, 130025, China
| | - Xiujuan Li
- The Key Laboratory of Engineering Bionic (Ministry of Education, China) and the College of Biological and Agricultural Engineering, Jilin University, 5988 Renmin Street, Changchun, 130025, China
| | - Luquan Ren
- The Key Laboratory of Engineering Bionic (Ministry of Education, China) and the College of Biological and Agricultural Engineering, Jilin University, 5988 Renmin Street, Changchun, 130025, China
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8
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Faußer AC, Dušek J, Čížková H, Kazda M. Diurnal dynamics of oxygen and carbon dioxide concentrations in shoots and rhizomes of a perennial in a constructed wetland indicate down-regulation of below ground oxygen consumption. AOB PLANTS 2016; 8:plw025. [PMID: 27207278 PMCID: PMC4940480 DOI: 10.1093/aobpla/plw025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 03/19/2016] [Indexed: 06/02/2023]
Abstract
Wetland plants actively provide oxygen for aerobic processes in submerged tissues and the rhizosphere. The novel concomitant assessment of diurnal dynamics of oxygen and carbon dioxide concentrations under field conditions tests the whole-system interactions in plant-internal gas exchange and regulation. Oxygen concentrations ([O2]) were monitored in-situ in central culm and rhizome pith cavities of common reed (Phragmites australis) using optical oxygen sensors. The corresponding carbon dioxide concentrations ([CO2]) were assessed via gas samples from the culms. Highly dynamic diurnal courses of [O2] were recorded, which started at 6.5-13 % in the morning, increased rapidly up to 22 % during midday and declined exponentially during the night. Internal [CO2] were high in the morning (1.55-17.5 %) and decreased (0.04-0.94 %) during the rapid increase of [O2] in the culms. The observed negative correlations between [O2] and [CO2] particularly describe the below ground relationship between plant-mediated oxygen supply and oxygen use by respiration and biogeochemical processes in the rhizosphere. Furthermore, the nocturnal declining slopes of [O2] in culms and rhizomes indicated a down-regulation of the demand for oxygen in the complete below ground plant-associated system. These findings emphasize the need for measurements of plant-internal gas exchange processes under field conditions because it considers the complex interactions in the oxic-anoxic interface.
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Affiliation(s)
- Anna C Faußer
- Ulm University, Institute of Systematic Botany and Ecology, Ulm, Germany
| | - Jiří Dušek
- CzechGlobe - Global Change Research Centre AS CR, Department of Matters and Energy Fluxes, v.v.i. České Budějovice, Czech Republic
| | - Hana Čížková
- CzechGlobe - Global Change Research Centre AS CR, Department of Matters and Energy Fluxes, v.v.i. České Budějovice, Czech Republic University of South Bohemia, Faculty of Agriculture, Department of Biology, České Budějovice, Czech Republic
| | - Marian Kazda
- Ulm University, Institute of Systematic Botany and Ecology, Ulm, Germany
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9
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Sage RF, Khoshravesh R. Passive CO2 concentration in higher plants. CURRENT OPINION IN PLANT BIOLOGY 2016; 31:58-65. [PMID: 27058940 DOI: 10.1016/j.pbi.2016.03.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 03/16/2016] [Accepted: 03/23/2016] [Indexed: 06/05/2023]
Abstract
Photorespiratory limitations on C3 photosynthesis are substantial in warm, low CO2 conditions. To compensate, certain plants evolved mechanisms to actively concentrate CO2 around Rubisco using ATP-supported CO2 pumps such as C4 photosynthesis. Plants can also passively accumulate CO2 without additional ATP expenditure by localizing the release of photorespired and respired CO2 around Rubisco that is diffusively isolated from peripheral air spaces. Passive accumulation of photorespired CO2 occurs when glycine decarboxylase is localized to vascular sheath cells in what is termed C2 photosynthesis, and through forming sheaths of chloroplasts around the periphery of mesophyll cells. The peripheral sheaths require photorespired CO2 to re-enter chloroplasts where it can be refixed. Passive accumulation of respiratory CO2 is common in organs such as stems, fruits and flowers, due to abundant heterotrophic tissues and high diffusive resistance along the organ periphery. Chloroplasts within these organs are able to exploit this high CO2 to reduce photorespiration. CO2 concentration can also be enhanced passively by channeling respired CO2 from roots and rhizomes into photosynthetic cells of stems and leaves via lacunae, aerenchyma and the xylem stream. Through passive CO2 concentration, C3 species likely improved their carbon economy and maintained fitness during episodes of low atmospheric CO2.
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Affiliation(s)
- Rowan F Sage
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON M5S3B2, Canada.
| | - Roxana Khoshravesh
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON M5S3B2, Canada
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11
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Reef R, Lovelock CE. Regulation of water balance in mangroves. ANNALS OF BOTANY 2015; 115:385-95. [PMID: 25157072 PMCID: PMC4332601 DOI: 10.1093/aob/mcu174] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 06/30/2014] [Indexed: 05/06/2023]
Abstract
BACKGROUND Mangroves are a group of highly salt-tolerant woody plants. The high water use efficiency of mangroves under saline conditions suggests that regulation of water transport is a crucial component of their salinity tolerance. SCOPE This review focuses on the processes that contribute to the ability of mangroves to maintain water uptake and limit water loss to the soil and the atmosphere under saline conditions, from micro to macro scales. These processes include: (1) efficient filtering of the incoming water to exclude salt; (2) maintenance of internal osmotic potentials lower than that of the rhizosphere; (3) water-saving properties; and (4) efficient exploitation of less-saline water sources when these become available. CONCLUSIONS Mangroves are inherently plastic and can change their structure at the root, leaf and stand levels in response to salinity in order to exclude salt from the xylem stream, maintain leaf hydraulic conductance, avoid cavitation and regulate water loss (e.g. suberization of roots and alterations of leaf size, succulence and angle, hydraulic anatomy and biomass partitioning). However, much is still unknown about the regulation of water uptake in mangroves, such as how they sense and respond to heterogeneity in root zone salinity, the extent to which they utilize non-stomatally derived CO2 as a water-saving measure and whether they can exploit atmospheric water sources.
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Affiliation(s)
- Ruth Reef
- School of Biological Sciences, The University of Queensland, St Lucia, QLD 4072, Australia
| | - Catherine E Lovelock
- School of Biological Sciences, The University of Queensland, St Lucia, QLD 4072, Australia
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12
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Witztum A, Wayne R. Fibre cables in the lacunae of Typha leaves contribute to a tensegrity structure. ANNALS OF BOTANY 2014; 113:789-797. [PMID: 24532647 PMCID: PMC3962244 DOI: 10.1093/aob/mcu002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 01/03/2014] [Indexed: 06/03/2023]
Abstract
BACKGROUND AND AIMS Cables composed of long, non-lignified fibre cells enclosed in a cover of much shorter thin-walled, crystal-containing cells traverse the air chambers (lacunae) in leaves of the taller species of Typha. The non-lignified fibre cables are anchored in diaphragms composed of stellate cells of aerenchyma tissue that segment the long air chambers into smaller compartments. Although the fibre cables are easily observed and can be pulled free from the porous-to-air diaphragms, their structure and function have been ignored or misinterpreted. METHODS Leaves of various species of Typha were dissected and fibre cables were pulled free and observed with a microscope using bright-field and polarizing optics. Maximal tensile strength of freshly removed cables was measured by hanging weights from fibre cables, and Instron analysis was used to produce curves of load versus extension until cables broke. KEY RESULTS AND CONCLUSIONS Polarized light microscopy revealed that the cellulose microfibrils that make up the walls of the cable fibres are oriented parallel to the long axis of the fibres. This orientation ensures that the fibre cables are mechanically stiff and strong under tension. Accordingly, the measured stiffness and tensile strength of the fibre cables were in the gigapascal range. In combination with the dorsal and ventral leaf surfaces and partitions that contain lignified fibre bundles and vascular strands that are strong in compression, the very fine fibre cables that are strong under tension form a tensegrity structure. The tensegrity structure creates multiple load paths through which stresses are redistributed throughout the 1-3 m tall upright leaves of Typha angustifolia, T. latifolia, T. × glauca, T. domingensis and T. shuttleworthii. The length of the fibre cables relative to the length of the leaf blades is reduced in the last-formed leaves of flowering individuals. Fibre cables are absent in the shorter leaves of Typha minima and, if present, only extend for a few centimetres from the sheath into the leaf blade of Typha laxmannii. The advantage of the structure of the Typha leaf blade, which enables stiffness to give way to flexibility under windy conditions, is discussed for both vegetative and flowering plants.
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Affiliation(s)
- Allan Witztum
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Randy Wayne
- Laboratory of Natural Philosophy, Department of Plant Biology, Cornell University, Ithaca, New York, USA
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13
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Matthews PGD, Seymour RS. Stomata actively regulate internal aeration of the sacred lotus Nelumbo nucifera. PLANT, CELL & ENVIRONMENT 2014; 37:402-413. [PMID: 23862628 DOI: 10.1111/pce.12163] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 07/01/2013] [Indexed: 06/02/2023]
Abstract
The sacred lotus Nelumbo nucifera (Gaertn.) possesses a complex system of gas canals that channel pressurized air from its leaves, down through its petioles and rhizomes, before venting this air back to the atmosphere through large stomata found in the centre of every lotus leaf. These central plate stomata (CPS) lie over a gas canal junction that connects with two-thirds of the gas canals within the leaf blade and with the larger of two discrete pairs of gas canals within the petiole that join with those in the rhizome. It is hypothesized that the lotus actively regulates the pressure, direction and rate of airflow within its gas canals by opening and closing these stomata. Impression casting the CPS reveal that they are open in the morning, close at midday and reopen in the afternoon. The periodic closure of the CPS during the day coincides with a temporary reversal in airflow direction within the petiolar gas canals. Experiments show that the conductance of the CPS decreases in response to increasing light level. This behaviour ventilates the rhizome and possibly directs benthic CO2 towards photosynthesis in the leaves. These results demonstrate a novel function for stomata: the active regulation of convective airflow.
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Affiliation(s)
- Philip G D Matthews
- Environmental Biology, University of Adelaide, Darling Building, DP 418, Adelaide, South Australia, 5005, Australia
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14
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Nishiuchi S, Yamauchi T, Takahashi H, Kotula L, Nakazono M. Mechanisms for coping with submergence and waterlogging in rice. RICE (NEW YORK, N.Y.) 2012; 5:2. [PMID: 24764502 PMCID: PMC3834488 DOI: 10.1186/1939-8433-5-2] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Accepted: 02/27/2012] [Indexed: 05/19/2023]
Abstract
Rice (Oryza sativa L.), unlike other cereals, can grow well in paddy fields and is highly tolerant of excess water stress, from either submergence (in which part or all of the plant is under water) or waterlogging (in which excess water in soil limits gas diffusion). Rice handles submergence stress by internal aeration and growth controls. A quiescence strategy based on Submergence-1A (SUB1A) or an escape strategy based on SNORKEL1 (SK1) and SNORKEL2 (SK2) is used for the growth controls. On the other hand, rice handles waterlogging stress by forming lysigenous aerenchyma and a barrier to radial O2 loss (ROL) in roots in order to supply O2 to the root tip. In this article, we summarize recent advances in understanding the mechanisms of responding to excess water stresses (i.e., submergence and waterlogging) in rice and other gramineous plants.
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Affiliation(s)
- Shunsaku Nishiuchi
- Laboratory of Plant Genetics and Breeding, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8601, Japan
| | - Takaki Yamauchi
- Laboratory of Plant Genetics and Breeding, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8601, Japan
| | - Hirokazu Takahashi
- Laboratory of Plant Genetics and Breeding, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8601, Japan
| | - Lukasz Kotula
- Laboratory of Plant Genetics and Breeding, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8601, Japan
| | - Mikio Nakazono
- Laboratory of Plant Genetics and Breeding, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa, Nagoya 464-8601, Japan
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Mühlenbock P, Plaszczyca M, Plaszczyca M, Mellerowicz E, Karpinski S. Lysigenous aerenchyma formation in Arabidopsis is controlled by LESION SIMULATING DISEASE1. THE PLANT CELL 2007; 19:3819-30. [PMID: 18055613 PMCID: PMC2174864 DOI: 10.1105/tpc.106.048843] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2006] [Revised: 10/19/2007] [Accepted: 10/31/2007] [Indexed: 05/18/2023]
Abstract
Aerenchyma tissues form gas-conducting tubes that provide roots with oxygen under hypoxic conditions. Although aerenchyma have received considerable attention in Zea mays, the signaling events and genes controlling aerenchyma induction remain elusive. Here, we show that Arabidopsis thaliana hypocotyls form lysigenous aerenchyma in response to hypoxia and that this process involves H(2)O(2) and ethylene signaling. By studying Arabidopsis mutants that are deregulated for excess light acclimation, cell death, and defense responses, we find that the formation of lysigenous aerenchyma depends on the plant defense regulators LESION SIMULATING DISEASE1 (LSD1), ENHANCED DISEASE SUSCEPIBILITY1 (EDS1), and PHYTOALEXIN DEFICIENT4 (PAD4) that operate upstream of ethylene and reactive oxygen species production. The obtained results indicate that programmed cell death of lysigenous aerenchyma in hypocotyls occurs in a similar but independent manner from the foliar programmed cell death. Thus, the induction of aerenchyma is subject to a genetic and tissue-specific program. The data lead us to conclude that the balanced activities of LSD1, EDS1, and PAD4 regulate lysigenous aerenchyma formation in response to hypoxia.
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Affiliation(s)
- Per Mühlenbock
- Institute of Plant Physiology, Polish Academy of Sciences, 30 239 Krakow, Poland
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