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Okamoto A, Koyama K, Bhusal N. Diurnal Change of the Photosynthetic Light-Response Curve of Buckbean ( Menyanthes trifoliata), an Emergent Aquatic Plant. PLANTS (BASEL, SWITZERLAND) 2022; 11:174. [PMID: 35050061 PMCID: PMC8779618 DOI: 10.3390/plants11020174] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/01/2022] [Accepted: 01/04/2022] [Indexed: 12/02/2022]
Abstract
Understanding plant physiological responses to high temperature is an important concern pertaining to climate change. However, compared with terrestrial plants, information about aquatic plants remains limited. Since the degree of midday depression of photosynthesis under high temperature depends on soil water conditions, it is expected that emergent aquatic plants, for which soil water conditions are always saturated, will show different patterns compared with terrestrial plants. We investigated the diurnal course of the photosynthetic light-response curve and incident light intensity for a freshwater emergent plant, buckbean (Menyanthes trifoliata L.; Menyanthaceae) in a cool temperate region. The effect of midday depression was observed only on a very hot day, but not on a moderately hot day, in summer. The diurnal course of photosynthetic light-response curves on this hot day showed that latent morning reduction of photosynthetic capacity started at dawn, preceding the apparent depression around the midday, in agreement with results reported in terrestrial plants. We concluded that (1) midday depression of emergent plants occurs when the stress intensity exceeds the species' tolerance, and (2) measurements of not only photosynthetic rate under field conditions but also diurnal course of photosynthetic light-response curve are necessary to quantify the effect of midday depression.
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Affiliation(s)
- Azumi Okamoto
- Department of Agro-Environmental Science, Obihiro University of Agriculture and Veterinary Medicine, Inadacho, Obihiro 080-8555, Japan
| | - Kohei Koyama
- Department of Agro-Environmental Science, Obihiro University of Agriculture and Veterinary Medicine, Inadacho, Obihiro 080-8555, Japan
| | - Narayan Bhusal
- Department of Agriculture, Forestry and Bioresources, Seoul National University, Seoul 08826, Korea;
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2
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Kamakura M, Kosugi Y, Takanashi S, Matsuo N, Uemura A, Lion M. Temporal fluctuation of patchy stomatal closure in leaves of <i>Dipterocarpus sublamellatus</i> at upper canopy in Peninsular Malaysia over the last decade. TROPICS 2021. [DOI: 10.3759/tropics.ms21-05] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Mai Kamakura
- Graduate School of Agriculture, Kyoto University
| | | | - Satoru Takanashi
- Forestry and Forest Products Research Institute, Kansai Research Center
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Tan PY, Wong NH, Tan CL, Jusuf SK, Schmiele K, Chiam ZQ. Transpiration and cooling potential of tropical urban trees from different native habitats. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 705:135764. [PMID: 31806315 DOI: 10.1016/j.scitotenv.2019.135764] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 11/23/2019] [Accepted: 11/24/2019] [Indexed: 06/10/2023]
Abstract
Urban trees are widely promoted as a solution to cool the urban environment because of shading and evaporative cooling provided by tree canopies. The extent to which the cooling benefits are realized is dependent not just on the genetically determined traits of trees, but also by their interactions with the atmospheric and edaphic conditions in urban areas, for which there is currently a paucity of information. We conducted a field experiment to compare whole-tree transpiration (Et) of tropical urban species from seasonally dry forest (SDF) (Tabebuia rosea, Lagerstroemia speciosa, Delonix regia, Caesalpinia ferrea, Dalbergia sissoo, Samanea saman) and aseasonal evergreen forest (AEF) (Peltophorum pterocarpum, Sindora wallichii). We examined the dependence of Et on atmospheric conditions (solar radiation (Rn) and vapor pressure deficit (VPD)), as well as on soil moisture level (θv). Daily Et differences between species were large but not statistically significant overall: 2000-3200 g m-2 (leaf area) under sunny conditions and 980-2000 g m-2 under cloudy conditions. The led to a daily latent heat flux (LE) of 770 W m-2 between the species with the highest (2136 W m-2) and lowest (1369 W m-2) daily Et. SDF species had higher daily Et than AEF species, but the difference was only significant under cloudy condition. Rn had a slightly stronger role in influencing transpiration compared to VPD, and species responses to drought stress differed marginally between the two groups. We assessed if two plant functional traits, wood density (ρw) and leaf stomatal conductance (gs), could be used to predict Et. Only gs was shown to be moderately correlated with Et, but more studies are needed to assess this given the limited number of species used in the study.
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Affiliation(s)
- Puay Yok Tan
- Department of Architecture, 4 Architecture Drive, National University of Singapore, Singapore 117566, Singapore.
| | - Nyuk Hien Wong
- Department of Building, 4 Architecture Drive, National University of Singapore, Singapore 117566, Singapore.
| | - Chun Liang Tan
- Department of Building, 4 Architecture Drive, National University of Singapore, Singapore 117566, Singapore.
| | | | - Kathrin Schmiele
- Department of Architecture, 4 Architecture Drive, National University of Singapore, Singapore 117566, Singapore.
| | - Zhi Quan Chiam
- Department of Architecture, 4 Architecture Drive, National University of Singapore, Singapore 117566, Singapore
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4
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Evaluation of the ENVI-Met Vegetation Model of Four Common Tree Species in a Subtropical Hot-Humid Area. ATMOSPHERE 2018. [DOI: 10.3390/atmos9050198] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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5
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Lion M, Kosugi Y, Takanashi S, Noguchi S, Itoh M, Katsuyama M, Matsuo N, Shamsuddin S. Evapotranspiration and water source of a tropical rainforest in peninsular Malaysia. HYDROLOGICAL PROCESSES 2017; 31:4338-4353. [PMID: 32336875 PMCID: PMC7165644 DOI: 10.1002/hyp.11360] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 09/13/2017] [Indexed: 06/11/2023]
Abstract
To evaluate water use and the supporting water source of a tropical rainforest, a 4-year assessment of evapotranspiration (ET) was conducted in Pasoh Forest Reserve, a lowland dipterocarp forest in Peninsular Malaysia. The eddy covariance method and isotope signals of rain, plant, soil, and stream waters were used to determine forest water sources under different moisture conditions. Four sampling events were conducted to collect soil and plant twig samples in wet, moderate, dry, and very dry conditions for the identification of isotopic signals. Annual ET from 2012 to 2015 was quite stable with an average of 1,182 ± 26 mm, and a substantial daily ET was observed even during drought periods, although some decline was observed, corresponding with volumetric soil water content. During the wet period, water for ET was supplied from the surface soil layer between 0 and 0.5 m, whereas in the dry period, approximately 50% to 90% was supplied from the deeper soil layer below 0.5-m depth, originating from water precipitated several months previously at this forest. Isotope signatures demonstrated that the water sources of the plants, soil, and stream were all different. Water in plants was often different from soil water, probably because plant water came from a different source than water that was strongly bound to the soil particles. Plants showed no preference for soil depth with their size, whereas the existence of storage water in the xylem was suggested. The evapotranspiration at this forest is balanced and maintained using most of the available water sources except for a proportion of rapid response run-off.
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Affiliation(s)
- Marryanna Lion
- Forest Research Institute Malaysia52109KepongSelangor Darul EhsanMalaysia
| | - Yoshiko Kosugi
- Graduate School of AgricultureKyoto UniversityKyoto606‐8502Japan
| | - Satoru Takanashi
- Kansai Research CenterForestry and Forest Products Research InstituteKyoto612‐0855Japan
| | - Shoji Noguchi
- Forestry and Forest Products Research Institute (FFPRI)TsukubaIbaraki305‐8687Japan
| | - Masayuki Itoh
- Center for Southeast Asian StudiesKyoto UniversityKyoto606‐8501Japan
| | - Masanori Katsuyama
- Center for the Promotion of Interdisciplinary Education and Research (C‐PIER)Kyoto UniversityHigashi Ichijokan, 1 Yoshida Nakaadachi, SakyoKyoto606‐8306Japan
| | - Naoko Matsuo
- Graduate School of BioresourcesMie UniversityTsuMie514‐8507Japan
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6
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Kamakura M, Kosugi Y, Takanashi S, Uemura A, Utsugi H, Kassim AR. Occurrence of stomatal patchiness and its spatial scale in leaves from various sizes of trees distributed in a South-east Asian tropical rainforest in Peninsular Malaysia. TREE PHYSIOLOGY 2015; 35:61-70. [PMID: 25595752 DOI: 10.1093/treephys/tpu109] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
In this study, we demonstrated the occurrence of stomatal patchiness and its spatial scale in leaves from various sizes of trees grown in a lowland dipterocarp forest in Peninsular Malaysia. To evaluate the patterns of stomatal behavior, we used three techniques simultaneously to analyze heterobaric or homobaric leaves from five tree species ranging from 0.6 to 31 m in height: (i) diurnal changes in chlorophyll fluorescence imaging, (ii) observation and simulation of leaf gas-exchange rates and (iii) a pressure-infiltration method. Measurements were performed in situ with 1000 or 500 μmol m(-2) s(-1) photosynthetic photon flux density. Diurnal patterns in the spatial distribution of photosynthetic electron transport rate (J) mapped from chlorophyll fluorescence images, a comparison of observed and simulated leaf gas-exchange rates, and the spatial distribution of stomatal apertures obtained from the acid-fuchsin-infiltrated area showed that patchy stomatal closure coupled with severe midday depression of photosynthesis occurred in Neobalanocarpus heimii (King) Ashton, a higher canopy tree with heterobaric leaves due to the higher leaf temperature and vapor pressure deficit. However, subcanopy or understory trees showed uniform stomatal behavior throughout the day, although they also have heterobaric leaves. These results suggest that the occurrence of stomatal patchiness is determined by tree size and/or environmental conditions. The analysis of spatial scale by chlorophyll fluorescence imaging showed that several adjacent anatomical patches (lamina areas bounded by bundle-sheath extensions within the lamina) may co-operate for the distributed patterns of J and stomatal apertures.
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Affiliation(s)
- Mai Kamakura
- Laboratory of Forest Hydrology, Division of Environmental Science and Technology, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
| | - Yoshiko Kosugi
- Laboratory of Forest Hydrology, Division of Environmental Science and Technology, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
| | - Satoru Takanashi
- Forestry and Forest Products Research Institute, Tsukuba, Ibaraki 305-8687, Japan
| | - Akira Uemura
- Hokkaido Research Center, Forestry and Forest Products Research Institute, Sapporo 062-8516, Japan
| | - Hajime Utsugi
- Forestry and Forest Products Research Institute, Tsukuba, Ibaraki 305-8687, Japan
| | - Abd Rahman Kassim
- Forest Research Institute Malaysia, Kepong, Selangor 52109, Malaysia
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7
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Kenzo T, Inoue Y, Yoshimura M, Yamashita M, Tanaka-Oda A, Ichie T. Height-related changes in leaf photosynthetic traits in diverse Bornean tropical rain forest trees. Oecologia 2014; 177:191-202. [PMID: 25362582 DOI: 10.1007/s00442-014-3126-0] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 10/17/2014] [Indexed: 10/24/2022]
Abstract
Knowledge of variations in morphophysiological leaf traits with forest height is essential for quantifying carbon and water fluxes from forest ecosystems. Here, we examined changes in leaf traits with forest height in diverse tree species and their role in environmental acclimation in a tropical rain forest in Borneo that does not experience dry spells. Height-related changes in leaf physiological and morphological traits [e.g., maximum photosynthetic rate (Amax), stomatal conductance (gs), dark respiration rate (Rd), carbon isotope ratio (δ(13)C), nitrogen (N) content, and leaf mass per area (LMA)] from understory to emergent trees were investigated in 104 species in 29 families. We found that many leaf area-based physiological traits (e.g., A(max-area), Rd, gs), N, δ(13)C, and LMA increased linearly with tree height, while leaf mass-based physiological traits (e.g., A(max-mass)) only increased slightly. These patterns differed from other biomes such as temperate and tropical dry forests, where trees usually show decreased photosynthetic capacity (e.g., A(max-area), A(max-mass)) with height. Increases in photosynthetic capacity, LMA, and δ(13)C are favored under bright and dry upper canopy conditions with higher photosynthetic productivity and drought tolerance, whereas lower R d and LMA may improve shade tolerance in lower canopy trees. Rapid recovery of leaf midday water potential to theoretical gravity potential during the night supports the idea that the majority of trees do not suffer from strong drought stress. Overall, leaf area-based photosynthetic traits were associated with tree height and the degree of leaf drought stress, even in diverse tropical rain forest trees.
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Affiliation(s)
- Tanaka Kenzo
- Department of Plant Ecology, Forestry and Forest Products Research Institute, Matsunosato 1, Tsukuba, Ibaraki, 305-8687, Japan,
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8
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Koyama K, Takemoto S. Morning reduction of photosynthetic capacity before midday depression. Sci Rep 2014; 4:4389. [PMID: 24633128 PMCID: PMC3955906 DOI: 10.1038/srep04389] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 02/28/2014] [Indexed: 11/09/2022] Open
Abstract
Midday depression of photosynthesis has important consequences for ecosystem carbon exchange. Recent studies of forest trees have demonstrated that latent reduction of photosynthetic capacity can begin in the early morning, preceding the midday depression. We investigated whether such early morning reduction also occurs in an herbaceous species, Oenothera biennis. Diurnal changes of the photosynthetic light response curve (measured using a light-emitting diode) and incident sunlight intensity were measured under field conditions. The following results were obtained: (1) the light-saturated photosynthetic rate decreased beginning at sunrise; (2) the incident sunlight intensity on the leaves increased from sunrise; and (3) combining (1) and (2), the net photosynthetic rate under natural sunlight intensity increased from sunrise, reached a maximum at mid-morning, and then showed midday depression. Our results demonstrate that the latent morning reduction of photosynthetic capacity begins at sunrise, preceding the apparent midday depression, in agreement with previous studies of forest trees.
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Affiliation(s)
- Kohei Koyama
- 1] Department of Life Science and Agriculture, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan [2] Department of Environmental Science, Ishikawa Prefectural University, Nonoichi, Ishikawa 921-8836, Japan
| | - Shuhei Takemoto
- The University of Tokyo Tanashi Forest, Graduate School of Agricultural & Life Sciences, 1-1-8 Midoricho, Nishitokyo, Tokyo 188-0002, Japan
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9
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Cernusak LA, Winter K, Dalling JW, Holtum JAM, Jaramillo C, K Rner C, Leakey ADB, Norby RJ, Poulter B, Turner BL, Wright SJ. Tropical forest responses to increasing atmospheric CO 2: current knowledge and opportunities for future research. FUNCTIONAL PLANT BIOLOGY : FPB 2013; 40:531-551. [PMID: 32481129 DOI: 10.1071/fp12309] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2012] [Accepted: 03/21/2013] [Indexed: 05/06/2023]
Abstract
Elevated atmospheric CO2 concentrations (ca) will undoubtedly affect the metabolism of tropical forests worldwide; however, critical aspects of how tropical forests will respond remain largely unknown. Here, we review the current state of knowledge about physiological and ecological responses, with the aim of providing a framework that can help to guide future experimental research. Modelling studies have indicated that elevated ca can potentially stimulate photosynthesis more in the tropics than at higher latitudes, because suppression of photorespiration by elevated ca increases with temperature. However, canopy leaves in tropical forests could also potentially reach a high temperature threshold under elevated ca that will moderate the rise in photosynthesis. Belowground responses, including fine root production, nutrient foraging and soil organic matter processing, will be especially important to the integrated ecosystem response to elevated ca. Water use efficiency will increase as ca rises, potentially impacting upon soil moisture status and nutrient availability. Recruitment may be differentially altered for some functional groups, potentially decreasing ecosystem carbon storage. Whole-forest CO2 enrichment experiments are urgently needed to test predictions of tropical forest functioning under elevated ca. Smaller scale experiments in the understorey and in gaps would also be informative, and could provide stepping stones towards stand-scale manipulations.
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Affiliation(s)
- Lucas A Cernusak
- School of Marine and Tropical Biology, James Cook University, Cairns, Qld 4878, Australia
| | - Klaus Winter
- Smithsonian Tropical Research Institute, PO Box 0843-03092, Balboa, Ancon, Republic of Panama
| | - James W Dalling
- Department of Plant Biology, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA
| | - Joseph A M Holtum
- Smithsonian Tropical Research Institute, PO Box 0843-03092, Balboa, Ancon, Republic of Panama
| | - Carlos Jaramillo
- Smithsonian Tropical Research Institute, PO Box 0843-03092, Balboa, Ancon, Republic of Panama
| | - Christian K Rner
- Institute of Botany, University of Basel, Basel, CH-4056, Switzerland
| | - Andrew D B Leakey
- Department of Plant Biology, University of Illinois, Urbana-Champaign, Urbana, IL 61801, USA
| | - Richard J Norby
- Environmental Sciences Division and Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Benjamin Poulter
- Laboratoire des Sciences du Climat et de l'Environnement, Gif sur Yvette French Centre National de la Recherche Scientifique, the Atomic Energy Commission and the University of Versailles Saint-Quentin, 91191, France
| | - Benjamin L Turner
- Smithsonian Tropical Research Institute, PO Box 0843-03092, Balboa, Ancon, Republic of Panama
| | - S Joseph Wright
- Smithsonian Tropical Research Institute, PO Box 0843-03092, Balboa, Ancon, Republic of Panama
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10
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Kosugi Y, Takanashi S, Yokoyama N, Philip E, Kamakura M. Vertical variation in leaf gas exchange parameters for a Southeast Asian tropical rainforest in Peninsular Malaysia. JOURNAL OF PLANT RESEARCH 2012; 125:735-748. [PMID: 22644315 DOI: 10.1007/s10265-012-0495-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Accepted: 04/18/2012] [Indexed: 06/01/2023]
Abstract
Vertical variation in leaf gas exchange characteristics of trees grown in a lowland dipterocarp forest in Peninsular Malaysia was investigated. Maximum net photosynthetic rate, stomatal conductance, and electron transport rate of leaves at the upper canopy, lower canopy, and forest floor were studied in situ with saturated condition photosynthetic photon flux density. The dark respiration rate of leaves at the various heights was also studied. Relationships among gas exchange characteristics, and also with nitrogen content per unit leaf area and leaf dry matter per area were clearly detected, forming general equations representing the vertical profile of several important parameters related to gas exchange. Numerical analysis revealed that the vertical distribution of gas exchange parameters was well determined showing both larger carbon gain for the whole canopy and at the same time positive carbon gain for the leaves of the lowest layer. For correct estimation of gas exchange at both leaf and canopy scales using multi-layer models, it is essential to consider the vertical distribution of gas exchange parameters with proper scaling coefficients.
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Affiliation(s)
- Yoshiko Kosugi
- Laboratory of Forest Hydrology, Division of Environmental Science and Technology, Graduate School of Agriculture, Kyoto University, Kyoto, 606-8502, Japan.
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11
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Kamakura M, Kosugi Y, Takanashi S, Tobita H, Uemura A, Utsugi H. Observation of the scale of patchy stomatal behavior in leaves of Quercus crispula using an Imaging-PAM chlorophyll fluorometer. TREE PHYSIOLOGY 2012; 32:839-846. [PMID: 22696269 DOI: 10.1093/treephys/tps053] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Patchy stomatal closure occurs in plants with heterobaric leaves, in which vertical extensions of bundle sheath cells delimit the mesophyll and restrict the diffusion of CO(2). The scale of patchy stomatal behavior was investigated in this study. The distribution of PSII quantum yield (Φ(II)) obtained from chlorophyll fluorescence images was used to evaluate the scale of stomatal patchiness and its relationship with leaf photosynthesis in the sun leaves of 2-year-old saplings of Quercus crispula Blume. Fluorescent patches were observed only during the day with low stomatal conductance. Comparison of numerical simulation of leaf gas exchange and chlorophyll fluorescence images showed that heterogeneous distribution of electron transport rate through PSII (J) was observed following stomatal closure with a bimodal manner under both natural and saturated photosynthetic photon flux densities. Thus, fluorescence patterns can be interpreted in terms of patchy stomatal closure. The mapping of J from chlorophyll fluorescence images showed that the scale of stomatal patchiness was approximately 2.5-fold larger than that of anatomical patches (lamina areas bounded by bundle sheath extensions within lamina). Our results suggest the spatial scale of stomatal patches in Q. crispula leaves.
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Affiliation(s)
- Mai Kamakura
- KYOUSEI Science Center for Life and Nature, Nara Women's University, Kita-uoya Higashimachi, Nara 630-8506, Japan.
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12
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Kamakura M, Kosugi Y, Muramatsu K, Muraoka H. Simulations and observations of patchy stomatal behavior in leaves of Quercus crispula, a cool-temperate deciduous broad-leaved tree species. JOURNAL OF PLANT RESEARCH 2012; 125:339-349. [PMID: 22020695 DOI: 10.1007/s10265-011-0460-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Accepted: 09/23/2011] [Indexed: 05/31/2023]
Abstract
We investigated the occurrence of patchy stomatal behavior in leaves of saplings and a forest canopy tree of Quercus crispula Blume. Through a combination of leaf gas-exchange measurements and numerical simulation, we detected patterns of stomatal closure (either uniform or patchy bimodal) coupled with depression of net assimilation rate (A). There was a clear inhibition of A associated with stomatal closure in leaves of Q. crispula during the day, but the magnitude of inhibition varied among days and growing conditions. Comparisons of observed and simulated A values for both saplings and the canopy tree identified patterns of stomatal behavior that shifted flexibly between uniform and patchy frequency distributions depending on environmental conditions. Bimodal stomatal closure explained severe depression of A in saplings under conditions of relatively high leaf temperature and vapor pressure deficit. Model simulations of A depression through bimodal stomatal closure were corroborated by direct observations of stomatal aperture distribution using Suzuki's Micro-Printing method; these demonstrated that there was a real bimodal frequency distribution of stomatal apertures. Although there was a heterogeneous distribution of stomatal apertures both within and among patches, induction of heterogeneity in intercellular CO₂ concentration among patches, and hence severe depression of A, resulted only from bimodal stomatal closure among patches (rather than within patches).
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Affiliation(s)
- Mai Kamakura
- KYOUSEI Science Center for Life and Nature, Nara Women's University, Kita-uoya Higashimachi, Nara 630-8506, Japan.
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Makita N, Kosugi Y, Dannoura M, Takanashi S, Niiyama K, Kassim AR, Nik AR. Patterns of root respiration rates and morphological traits in 13 tree species in a tropical forest. TREE PHYSIOLOGY 2012; 32:303-312. [PMID: 22367761 DOI: 10.1093/treephys/tps008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The root systems of forest trees are composed of different diameters and heterogeneous physiological traits. However, the pattern of root respiration rates from finer and coarser roots across various tropical species remains unknown. To clarify how respiration is related to the morphological traits of roots, we evaluated specific root respiration and its relationships to mean root diameter (D) of various diameter and root tissue density (RTD; root mass per unit root volume; gcm(-3)) and specific root length (SRL; root length per unit root mass; mg(-1)) of the fine roots among and within 14 trees of 13 species from a primary tropical rainforest in the Pasoh Forest Reserve in Peninsular Malaysia. Coarse root (2-269mm) respiration rates increased with decreasing D, resulting in significant relationships between root respiration and diameter across species. A model based on a radial gradient of respiration rates of coarse roots simulated the exponential decrease in respiration with diameter. The respiration rate of fine roots (<2mm) was much higher and more variable than those of larger diameter roots. For fine roots, the mean respiration rates for each species increased with decreasing D. The respiration rates of fine roots declined markedly with increasing RTD and increased with increasing SRL, which explained a significant portion of the variation in the respiration among the 14 trees from 13 species examined. Our results indicate that coarse root respiration in tree species follows a basic relationship with D across species and that most of the variation in fine root respiration among species is explained by D, RTD and SRL. We found that the relationship between root respiration and morphological traits provides a quantitative basis for separating fine roots from coarse roots and that the pattern holds across different species.
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Affiliation(s)
- Naoki Makita
- Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan.
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14
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Corlett RT. Impacts of warming on tropical lowland rainforests. Trends Ecol Evol 2011; 26:606-13. [DOI: 10.1016/j.tree.2011.06.015] [Citation(s) in RCA: 161] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Revised: 06/26/2011] [Accepted: 06/27/2011] [Indexed: 10/17/2022]
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15
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Kamakura M, Kosugi Y, Takanashi S, Matsumoto K, Okumura M, Philip E. Patchy stomatal behavior during midday depression of leaf CO₂ exchange in tropical trees. TREE PHYSIOLOGY 2011; 31:160-168. [PMID: 21383025 DOI: 10.1093/treephys/tpq102] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We investigated effects of heterogeneous stomatal behavior on diurnal patterns of leaf gas exchange in 10 tree species. Observations were made in middle and upper canopy layers of potted tropical rainforest trees in a nursery at the Forest Research Institute Malaysia. Measurements were taken from 29 January to 3 February 2010. We measured in situ diurnal changes in net photosynthetic rate and stomatal conductance in three leaves of each species under natural light. In both top-canopy and sub-canopy species, midday depression of net assimilation rate occurred in late morning. Numerical analysis showed that patchy bimodal stomatal behavior occurred only during midday depression, suggesting that the distribution pattern of stomatal apertures (either uniform or non-uniform stomatal behavior) varies flexibly within single days. Direct observation of stomatal aperture using Suzuki's Universal Micro-Printing (SUMP) method demonstrated midday patchy stomatal closure that fits a bimodal pattern in Shorea leprosula Miq., Shorea macrantha Brandis. and Dipterocarpus tempehes V.Sl. Inhibition of net assimilation rate and stomatal conductance appears to be a response to changes in vapor pressure deficit (VPD). Variable stomatal closure with increasing VPD is a mechanism used by a range of species to prevent excess water loss from leaves through evapotranspiration (viz., inhibition of midday leaf gas exchange). Bimodal stomatal closure may occur among adjacent stomata within a single patch, rather than among patches on a single leaf. Our results suggest the occurrence of patches at several scales within single leaves. Further analysis should consider variable spatial scales in heterogeneous stomatal behavior between and within patches and within single leaves.
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Affiliation(s)
- Mai Kamakura
- KYOUSEI Science Center for Life and Nature, Nara Women's University, Kita-uoya Higashimachi, Nara, Japan.
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