scholarly journals Integrating plant hydraulics and gas exchange along the drought-response trait spectrum

2014 ◽  
Vol 34 (10) ◽  
pp. 1031-1034 ◽  
Author(s):  
S. Manzoni
2020 ◽  
Author(s):  
Wellington L Almeida ◽  
Rodrigo T Ávila ◽  
Junior P Pérez-Molina ◽  
Marcela L Barbosa ◽  
Dinorah M S Marçal ◽  
...  

Abstract The overall coordination between gas exchanges and plant hydraulics may be affected by soil water availability and source-to-sink relationships. Here we evaluated how branch growth and mortality, leaf gas exchange and metabolism are affected in coffee (Coffea arabica L.) trees by drought and fruiting. Field-grown plants were irrigated or not, and maintained with full or no fruit load. Under mild water deficit, irrigation per se did not significantly impact growth but markedly reduced branch mortality in fruiting trees, despite similar leaf assimilate pools and water status. Fruiting increased net photosynthetic rate in parallel with an enhanced stomatal conductance, particularly in irrigated plants. Mesophyll conductance and maximum RuBisCO carboxylation rate remained unchanged across treatments. The increased stomatal conductance in fruiting trees over nonfruiting ones was unrelated to internal CO2 concentration, foliar abscisic acid (ABA) levels or differential ABA sensitivity. However, stomatal conductance was associated with higher stomatal density, lower stomatal sensitivity to vapor pressure deficit, and higher leaf hydraulic conductance and capacitance. Increased leaf transpiration rate in fruiting trees was supported by coordinated alterations in plant hydraulics, which explained the maintenance of plant water status. Finally, by preventing branch mortality, irrigation can mitigate biennial production fluctuations and improve the sustainability of coffee plantations.


OENO One ◽  
2017 ◽  
Vol 51 (1) ◽  
Author(s):  
Vivian Zufferey ◽  
Jean-Laurent Spring ◽  
Thibaut Verdenal ◽  
Agnès Dienes ◽  
Sandrine Belcher ◽  
...  

<p><strong>Aims : </strong>The aims of this study were to investigate the physiological behavior (plant hydraulics, gas exchange) of the cultivar Pinot Noir in the field under progressively increasing conditions of water stress and analyze the effects of drought on grape and wine quality.</p><p><strong>Methods and results : </strong>Grapevines of the variety <em>Vitis vinifera</em> L. cv. Pinot Noir (clone 9-18, grafted onto 5BB) were subjected to different water regimes (irrigation treatments) over the growing season. Physiological indicators were used to monitor plant water status (leaf and stem water potentials and relative carbon isotope composition (d<sup>13</sup>C) in must sugars). Leaf gas exchange (net photosynthesis A and transpiration E), leaf stomatal conductance (gs), specific hydraulic conductivity in petioles (K<sub>petiole</sub>), yield components, berry composition at harvest, and organoleptic quality of wines were analyzed over a 7-year period, between 2009 and 2015, under relatively dry conditions in the canton of Wallis, Switzerland. A progressively increasing water deficit, observed throughout the season, reduced the leaf gas exchange (A and E) and gs in non-irrigated vines. The intrinsic water use efficiency (WUE<sub>i</sub>, A/gs) increased during the growing season and was greater in water-stressed vines than in well-watered vines (irrigated vines). This rise in WUE<sub>i</sub> was correlated with an increase in d<sup>13</sup>C in must sugars at harvest. Drought led to decreases in K<sub>petiole</sub>, E and sap flow in stems. A decrease in vine plant vigor was observed in vines that had been subjected to water deficits year after year. Moderate water stress during ripening favored sugar accumulation in berries and caused a reduction in total acidic and malic contents in must and available nitrogen content (YAN). Wines produced from water-stressed vines had a deeper color and were richer in anthocyanins and phenol compounds compared with wines from well-watered vines with no water stress. The vine water status greatly influenced the organoleptic quality of the resulting wines. Wines made from non-irrigated vines with a water deficit presented more structure and higher-quality tannins. They were also judged to be more full-bodied and with blended tannins than those made from irrigated vines.</p><p><strong>Conclusions : </strong>Grape ripening and resulting Pinot Noir wines were found to be largely dependent on the water supply conditions of the vines during the growing season, which influenced gas exchange and plant hydraulics.</p><p><strong>Significance and impact of the study : </strong>Plant water status constitutes a key factor in leaf gas exchange, canopy water use efficiency, berry composition and wine quality.</p>


Lab on a Chip ◽  
2017 ◽  
Vol 17 (23) ◽  
pp. 4015-4024 ◽  
Author(s):  
Volodymyr B. Koman ◽  
Tedrick T. S. Lew ◽  
Min Hao Wong ◽  
Seon-Yeong Kwak ◽  
Juan P. Giraldo ◽  
...  

Stomatal function can be used effectively to monitor plant hydraulics, photosensitivity, and gas exchange.


1992 ◽  
Vol 117 (5) ◽  
pp. 834-840 ◽  
Author(s):  
Mark Rieger

Growth, gas exchange, root hydraulic conductivity, and drought response of seedling and rooted cuttings of Lovell and Nemaguard peach [Prunus persica (L.) Batsch], and Carrizo (Poncirus trifoliata × Citrus sinensis) and sour orange (C. aurantium L.) citrus rootstocks were compared to determine the influence of propagation method on these characteristics. Rooted peach cuttings had a higher proportion of root biomass in fibrous roots (≤ mm in diameter) and lower root: shoot ratios than seedlings, although this did not occur in citrus. Net CO2 assimilation (A) was higher for peach seedlings than for cuttings, but similar for `Redhaven' (RH) scions on either seedling- or cutting-propagated rootstocks, suggesting that leaf-associated factors were responsible for differences. As in peach, A was higher for Carrizo seedlings than for cuttings, but A was not affected by propagation method in sour orange. Peach seedlings maintained higher A than cuttings as water potentials declined during short-term soil drying, although in citrus this occurred only for Carrizo. RH scions on either root type exhibited similar declines in A as soil dried, indicating the lack of a rootstock effect. Root hydraulic conductivity (Lp) was similar between seedlings and cuttings of all cultivars when expressed on a length basis. Leaf conductance and osmotic adjustment were similar for RH scions on seedling- or cutting-propogated rootstocks during 45 days of drought stress, indicating the lack of a rootstock effect on long-term stress response.


2020 ◽  
Author(s):  
Yanlan Liu ◽  
Nataniel M. Holtzman ◽  
Alexandra G. Konings

Abstract. Droughts are expected to become more frequent and severe under climate change, increasing the need for accurate predictions of plant drought response. This response varies substantially depending on plant properties that regulate water transport and storage within plants, i.e., plant hydraulic traits. It is therefore crucial to map plant hydraulic traits at a large scale to better assess drought impacts. Improved understanding of global variations in plant hydraulic traits is also needed for paramaterizing the latest generation of land surface models, many of which explicitly simulate plant hydraulic processes for the first time. Here, we use a model-data fusion approach to evaluate the spatial pattern of plant hydraulic traits across the globe. This approach integrates a plant hydraulic model with datasets derived from microwave remote sensing that inform ecosystem-scale plant water regulation. In particular, we use both surface soil moisture and vegetation optical depth (VOD) derived from the X-band JAXA Advanced Microwave Scanning Radiometer for EOS (AMSR-E). VOD is proportional to vegetation water content and therefore closely related to leaf water potential. In addition, evapotranspiration (ET) from the Atmosphere Land-Exchange Inverse model (ALEXI) is also used as a constraint to derive plant hydraulic traits. The derived traits are compared to independent data sources based on ground measurements. Using the K-means clustering method, we build six hydraulic functional types (HFTs) with distinct trait combinations – mathematically tractable alternatives to the common approach of assigning plant hydraulic values based on plant functional types. Using traits averaged by HFTs rather than by PFTs improves VOD and ET estimation accuracies in the majority of areas across the globe. The use of HFTs and/or plant hydraulic traits derived from model-data fusion in this study will contribute to improved parameterization of plant hydraulics in large-scale models and the prediction of ecosystem drought response.


2021 ◽  
Vol 25 (5) ◽  
pp. 2399-2417
Author(s):  
Yanlan Liu ◽  
Nataniel M. Holtzman ◽  
Alexandra G. Konings

Abstract. Droughts are expected to become more frequent and severe under climate change, increasing the need for accurate predictions of plant drought response. This response varies substantially, depending on plant properties that regulate water transport and storage within plants, i.e., plant hydraulic traits. It is, therefore, crucial to map plant hydraulic traits at a large scale to better assess drought impacts. Improved understanding of global variations in plant hydraulic traits is also needed for parameterizing the latest generation of land surface models, many of which explicitly simulate plant hydraulic processes for the first time. Here, we use a model–data fusion approach to evaluate the spatial pattern of plant hydraulic traits across the globe. This approach integrates a plant hydraulic model with data sets derived from microwave remote sensing that inform ecosystem-scale plant water regulation. In particular, we use both surface soil moisture and vegetation optical depth (VOD) derived from the X-band Japan Aerospace Exploration Agency (JAXA) Advanced Microwave Scanning Radiometer for Earth Observing System (EOS; collectively AMSR-E). VOD is proportional to vegetation water content and, therefore, closely related to leaf water potential. In addition, evapotranspiration (ET) from the Atmosphere–Land Exchange Inverse (ALEXI) model is also used as a constraint to derive plant hydraulic traits. The derived traits are compared to independent data sources based on ground measurements. Using the K-means clustering method, we build six hydraulic functional types (HFTs) with distinct trait combinations – mathematically tractable alternatives to the common approach of assigning plant hydraulic values based on plant functional types. Using traits averaged by HFTs rather than by plant functional types (PFTs) improves VOD and ET estimation accuracies in the majority of areas across the globe. The use of HFTs and/or plant hydraulic traits derived from model–data fusion in this study will contribute to improved parameterization of plant hydraulics in large-scale models and the prediction of ecosystem drought response.


2005 ◽  
Vol 275 (1-2) ◽  
pp. 337-348 ◽  
Author(s):  
Maria Balota ◽  
C.M. Rush ◽  
W.A. Payne ◽  
M.D. Lazar

2021 ◽  
Author(s):  
Manon Sabot ◽  
Martin De Kauwe ◽  
Andy Pitman ◽  
Belinda Medlyn ◽  
Silvia Caldararu ◽  
...  

&lt;p&gt;Droughts have been implicated as the driver behind recent vegetation die-off across a variety of hydroclimates and are projected to drive greater mortality under future climate change. Predicting ecosystem resilience to future drought requires a predictive capacity, which is currently lacking in state-of-the-art land surface models (LSMs) that rely on simplified empirical relationships to represent the impacts of water stress on vegetation. Novel approaches that optimise stomatal conductance with respect to plant photosynthetic and hydraulic functions have been shown to reduce the biases of LSM gas exchange predictions during drought. These approaches also offer a pathway to further develop mechanistic optimality theory, e.g. pertaining to leaf drought deciduousness. But on what timescale(s) does vegetation function adjust to maximise resource investment? We explore the following timescales of optimality within a simple LSM: (i) instantaneous (regulating canopy gas exchange); (ii) monthly (regulating the investment of nitrogen in photosynthetic capacity); and (iii) seasonal to annual (water stress legacies on plant hydraulics). We use observations from a temperate woodland in South-Eastern Australia to test which optimisation timescales and processes are best supported and whether competing timescales can operate together, both under well-watered conditions and during a severe multi-year drought, and from the leaf-scale to the ecosystem-scale. The insights gained help us characterize how adjoined allocation processes, like leaf biomass adjustment, relate to leaf carbon uptake and plant water status through time (e.g. leaves can be shed to mitigate drought stress or built from structural storage pools when water is not limiting), therefore conferring additional resilience.&lt;/p&gt;


2000 ◽  
Vol 125 (3) ◽  
pp. 310-317 ◽  
Author(s):  
Kelly J. Prevete ◽  
R. Thomas Fernandez ◽  
William B. Miller

Boltonia asteroides L. `Snowbank' (Snowbank boltonia), Eupatorium rugosum L. (eastern white snakeroot), and Rudbeckia triloba L. (three-lobed coneflower) were subjected to drought for 2, 4, and 6 days during the fall and spring. Leaf gas exchange, leaf water potential, growth, and carbohydrate partitioning were measured during drought and throughout the following growing season. Leaf gas exchange of B. asteroides was not affected by drought treatment in the fall, not until day 6 of spring drought, and there were no long-term effects on growth. Transpiration and stomatal conductance of R. triloba decreased when substrate moisture decreased to 21% after drought treatment during both seasons. Assimilation of drought-treated R. triloba decreased when substrate moisture content decreased to 12% during spring but was not affected by drought in the fall. There was a decrease in the root-to-shoot ratio of R. triloba that had been treated for 4 days, which was attributed to an increase in the shoot dry weight (DW) of treated plants. Reductions in spring growth of E. rugosum were observed only after fall drought of 6 days, and there were no differences in final DWs of plants subjected to any of the drought durations. Spring drought had no effect on growth index or DW of any of the perennials. Boltonia asteroides and R. triloba had increases in low-molecular-weight sugars on day 4 of drought, but E. rugosum did not have an increase in sugars of low molecular weight until day 6 of drought. Differences in drought response of B. asteroides, E. rugosum, and R. triloba were attributed to differences in water use rates.


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