1
|
Sun W, Maseyk K, Lett C, Seibt U. Restricted internal diffusion weakens transpiration-photosynthesis coupling during heatwaves: Evidence from leaf carbonyl sulphide exchange. PLANT, CELL & ENVIRONMENT 2024; 47:1813-1833. [PMID: 38321806 DOI: 10.1111/pce.14840] [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: 04/19/2023] [Revised: 11/13/2023] [Accepted: 01/22/2024] [Indexed: 02/08/2024]
Abstract
Increasingly frequent and intense heatwaves threaten ecosystem health in a warming climate. However, plant responses to heatwaves are poorly understood. A key uncertainty concerns the intensification of transpiration when heatwaves suppress photosynthesis, known as transpiration-photosynthesis decoupling. Field observations of such decoupling are scarce, and the underlying physiological mechanisms remain elusive. Here, we use carbonyl sulphide (COS) as a leaf gas exchange tracer to examine potential mechanisms leading to transpiration-photosynthesis decoupling on a coast live oak in a southern California woodland in spring 2013. We found that heatwaves suppressed both photosynthesis and leaf COS uptake but increased transpiration or sustained it at non-heatwave levels throughout the day. Despite statistically significant decoupling between transpiration and photosynthesis, stomatal sensitivity to environmental factors did not change during heatwaves. Instead, midday photosynthesis during heatwaves was restricted by internal diffusion, as indicated by the lower internal conductance to COS. Thus, increased evaporative demand and nonstomatal limitation to photosynthesis act jointly to decouple transpiration from photosynthesis without altering stomatal sensitivity. Decoupling offered limited potential cooling benefits, questioning its effectiveness for leaf thermoregulation in xeric ecosystems. We suggest that adding COS to leaf and ecosystem flux measurements helps elucidate diverse physiological mechanisms underlying transpiration-photosynthesis decoupling.
Collapse
Affiliation(s)
- Wu Sun
- Department of Global Ecology, Carnegie Institution for Science, Stanford, California, USA
| | - Kadmiel Maseyk
- School of Environment, Earth and Ecosystem Sciences, The Open University, Milton Keynes, UK
| | - Céline Lett
- Department of Environmental Research and Innovation, Luxembourg Institute of Science and Technology, Belvaux, Luxembourg
| | - Ulli Seibt
- Department of Atmospheric and Oceanic Sciences, University of California, Los Angeles, California, USA
| |
Collapse
|
2
|
Muller JD, Rotenberg E, Tatarinov F, Oz I, Yakir D. Detailed in situ leaf energy budget permits the assessment of leaf aerodynamic resistance as a key to enhance non-evaporative cooling under drought. PLANT, CELL & ENVIRONMENT 2023; 46:3128-3143. [PMID: 36794448 DOI: 10.1111/pce.14571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 02/03/2023] [Accepted: 02/13/2023] [Indexed: 06/18/2023]
Abstract
The modulation of the leaf energy budget components to maintain optimal leaf temperature are fundamental aspects of plant functioning and survival. Better understanding these aspects becomes increasingly important under a drying and warming climate when cooling through evapotranspiration (E) is suppressed. Combining novel measurements and theoretical estimates, we obtained unusually comprehensive twig-scale leaf energy budgets under extreme field conditions in droughted (suppressed E) and non-droughted (enhanced E) plots of a semi-arid pine forest. Under the same high mid-summer radiative load, leaf cooling shifted from relying on nearly equal contributions of sensible (H) and latent (LE) energy fluxes in non-droughted trees to relying almost exclusively on H in droughted ones, with no change in leaf temperature. Relying on our detailed leaf energy budget, we could demonstrate that this is due to a 2× reduction in leaf aerodynamic resistance. This capability for LE-to-H shift in leaves of mature Aleppo pine trees under droughted field conditions without increasing leaf temperature is likely a critical factor in the resilience and relatively high productivity of this important Mediterranean tree species under drying conditions.
Collapse
Affiliation(s)
- Jonathan D Muller
- Earth & Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Eyal Rotenberg
- Earth & Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Fyodor Tatarinov
- Earth & Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Itay Oz
- Earth & Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Dan Yakir
- Earth & Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel
| |
Collapse
|
3
|
Bei Z, Zhang X, Tian X. The Mechanism by Which Umbrella-Shaped Ratchet Trichomes on the Elaeagnus angustifolia Leaf Surface Collect Water and Reflect Light. BIOLOGY 2023; 12:1024. [PMID: 37508453 PMCID: PMC10376016 DOI: 10.3390/biology12071024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 07/18/2023] [Accepted: 07/18/2023] [Indexed: 07/30/2023]
Abstract
Leaves are essential for plants, enabling photosynthesis and transpiration. In arid regions, water availability limits plant growth. Some plants, like Elaeagnus angustifolia, a sandy sub-tree species widely distributed in arid and semi-arid regions, have unique leaf structures to reduce water loss and solar radiation. Here, we describe the leaves of Elaeagnus angustifolia L., with special functioning trichomes. Through leaf submicroscopic structure observation, in situ water collection experiments, photosynthesis measurements, and reflection spectrum analysis, we investigated E. angustifolia leaves, focusing on their functioning trichomes. These trichomes capture water vapor, reflect UV and NIR light, and possess a 3D interface structure composed of 1D and 2D structures. The 1D conical structure captures water droplets, which are then gathered by the radial conical structure and guided towards the stomata through wedge-shaped grooves on the 2D umbrella structure. The trichomes also reflect sunlight, with micropapillae reflecting UV light and the umbrella structure reflecting NIR light. These mechanisms reduce leaf temperature, respiration, and water transpiration, protecting against solar radiation damage. This study provides insights into water collection and light-reflection mechanisms, revealing adaptive strategies of plants with large leaves in arid regions.
Collapse
Affiliation(s)
- Zhanlin Bei
- School of Life Sciences, Nanjing University, Nanjing 210023, China
- School of Biological Science and Engineering, North Minzu University, Yinchuan 750021, China
| | - Xin Zhang
- School of Biological Science and Engineering, North Minzu University, Yinchuan 750021, China
| | - Xingjun Tian
- School of Life Sciences, Nanjing University, Nanjing 210023, China
| |
Collapse
|
4
|
Kothari S, Beauchamp‐Rioux R, Laliberté E, Cavender‐Bares J. Reflectance spectroscopy allows rapid, accurate and non‐destructive estimates of functional traits from pressed leaves. Methods Ecol Evol 2022. [DOI: 10.1111/2041-210x.13958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Shan Kothari
- Department of Plant and Microbial Biology University of Minnesota St. Paul MN USA
- Institut de recherche en biologie végétale, Département de sciences biologiques Université de Montréal Montréal QC Canada
| | - Rosalie Beauchamp‐Rioux
- Institut de recherche en biologie végétale, Département de sciences biologiques Université de Montréal Montréal QC Canada
| | - Etienne Laliberté
- Institut de recherche en biologie végétale, Département de sciences biologiques Université de Montréal Montréal QC Canada
| | - Jeannine Cavender‐Bares
- Department of Plant and Microbial Biology University of Minnesota St. Paul MN USA
- Department of Ecology, Evolution, and Behavior University of Minnesota St. Paul MN USA
| |
Collapse
|
5
|
Inferring Agronomical Insights for Wheat Canopy Using Image-Based Curve Fit
K
-Means Segmentation Algorithm and Statistical Analysis. Int J Genomics 2022; 2022:1875013. [PMID: 35141328 PMCID: PMC8820929 DOI: 10.1155/2022/1875013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 12/15/2021] [Accepted: 12/21/2021] [Indexed: 11/19/2022] Open
Abstract
Phenomics and chlorophyll fluorescence can help us to understand the various stresses a plant may undergo. In this research work, we observe the image-based morphological changes in the wheat canopy. These changes are monitored by capturing the maximum area of wheat canopy image that has maximum photosynthetic activity (chlorophyll fluorescence signals). The proposed algorithm presented here has three stages: (i) first, derivation of dynamic threshold value by curve fitting of data to eliminate the pixels of low-intensity value, (ii) second, extraction and segmentation of thresholded region by application of histogram-based K-means algorithm iteratively (this scheme of the algorithm is referred to as the curve fit K-means (CfitK-means) algorithm); and (iii) third, computation of 23 grey level cooccurrence matrix (GLCM) texture features (traits) from the wheat images has been done. These features help to do statistical analysis and infer agronomical insights. The analysis consists of correlation, factor, and agglomerative clustering to identify water stress indicators. A public repository of wheat canopy images was used that had normal and water stress response chlorophyll fluorescence images. The analysis of the feature dataset shows that all 23 features are proved fruitful in studying the changes in the shape and structure of wheat canopy due to water stress. The best segmentation algorithm was confirmed by doing exhaustive comparisons of seven segmentation algorithms. The comparisons showed that the best algorithm is CfitK-means as it has a maximum IoU score value of 95.75.
Collapse
|
6
|
Muller JD, Rotenberg E, Tatarinov F, Vishnevetsky I, Dingjan T, Kribus A, Yakir D. 'Dual-reference' method for high-precision infrared measurement of leaf surface temperature under field conditions. THE NEW PHYTOLOGIST 2021; 232:2535-2546. [PMID: 34480755 DOI: 10.1111/nph.17720] [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: 04/25/2021] [Accepted: 08/09/2021] [Indexed: 06/13/2023]
Abstract
Temperature is a key control over biological activities from the cellular to the ecosystem scales. However, direct, high-precision measurements of surface temperature of small objects, such as leaves, under field conditions with large variations in ambient conditions remain rare. Contact methods, such as thermocouples, are prone to large errors. The use of noncontact remote-sensing methods, such as thermal infrared measurements, provides an ideal solution, but their accuracy has been low (c. 2°C) owing to the necessity for corrections for material emissivity and fluctuations in background radiation Lbg . A novel 'dual-reference' method was developed to increase the accuracy of infrared needle-leaf surface temperature measurements in the field. It accounts for variations in Lbg and corrects for the systematic camera offset using two reference plates. We accurately captured surface temperature and leaf-to-air temperature differences of needle-leaves in a forest ecosystem with large diurnal and seasonal temperature fluctuations with an uncertainty of ± 0.23°C and ± 0.28°C, respectively. Routine high-precision leaf temperature measurements even under harsh field conditions, such as demonstrated here, opens the way for investigating a wide range of leaf-scale processes and their dynamics.
Collapse
Affiliation(s)
- Jonathan D Muller
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, 7610001, Rehovot, Israel
| | - Eyal Rotenberg
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, 7610001, Rehovot, Israel
| | - Fyodor Tatarinov
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, 7610001, Rehovot, Israel
| | - Irina Vishnevetsky
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, 7610001, Rehovot, Israel
| | - Tamir Dingjan
- Department of Biomolecular Sciences, Weizmann Institute of Science, 7610001, Rehovot, Israel
| | - Abraham Kribus
- School of Mechanical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Dan Yakir
- Department of Earth and Planetary Sciences, Weizmann Institute of Science, 7610001, Rehovot, Israel
| |
Collapse
|
7
|
Muller JD, Rotenberg E, Tatarinov F, Oz I, Yakir D. Evidence for efficient nonevaporative leaf-to-air heat dissipation in a pine forest under drought conditions. THE NEW PHYTOLOGIST 2021; 232:2254-2266. [PMID: 34536983 DOI: 10.1111/nph.17742] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Accepted: 09/04/2021] [Indexed: 06/13/2023]
Abstract
The drier climates predicted for many regions will result in reduced evaporative cooling, leading to leaf heat stress and enhanced mortality. The extent to which nonevaporative cooling can contribute to plant resilience under these increasingly stressful conditions is not well known at present. Using a novel, high accuracy infrared system for the continuous measurement of leaf temperature in mature trees under field conditions, we assessed leaf-to-air temperature differences (ΔTleaf-air ) of pine needles during drought. On mid-summer days, ΔTleaf-air remained < 3°C, both in trees exposed to summer drought and in those provided with supplemental irrigation, which had a more than 10-fold higher transpiration rate. The nonevaporative cooling in the drought-exposed trees must be facilitated by low resistance to heat transfer, generating a large sensible heat flux, H. ΔTleaf-air was weakly related to variations in the radiation load and mean wind speed in the lower part of the canopy, but was dependent on canopy structure and within-canopy turbulence that enhanced the H. Nonevaporative cooling is demonstrated as an effective cooling mechanism in needle-leaf trees which can be a critical factor in forest resistance to drying climates. The generation of a large H at the leaf scale provides a basis for the development of the previously identified canopy-scale 'convector effect'.
Collapse
Affiliation(s)
- Jonathan D Muller
- Earth & Planetary Sciences, Weizmann Institute of Science, 7610001, Rehovot, Israel
| | - Eyal Rotenberg
- Earth & Planetary Sciences, Weizmann Institute of Science, 7610001, Rehovot, Israel
| | - Fyodor Tatarinov
- Earth & Planetary Sciences, Weizmann Institute of Science, 7610001, Rehovot, Israel
| | - Itay Oz
- Earth & Planetary Sciences, Weizmann Institute of Science, 7610001, Rehovot, Israel
| | - Dan Yakir
- Earth & Planetary Sciences, Weizmann Institute of Science, 7610001, Rehovot, Israel
| |
Collapse
|