Tropical rainforests under severe drought stress: distinct water use strategies among and within species

2021 ◽  
Author(s):  
Angelika Kübert ◽  
Kathrin Kühnhammer ◽  
Ines Bamberger ◽  
Erik Daber ◽  
Jason De Leeuw ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Soil Water ◽  
Water Use ◽  
Leaf Gas Exchange ◽  
Physiological Responses ◽  
Leaf Water ◽  
Severe Drought ◽  
Subsequent Recovery ◽  
Species Specific

<p>Increasing drought in the tropics is a major threat to rainforests and can strongly harm plant communities. Understanding species-specific water use strategies to drought and the subsequent recovery is therefore important for estimating the risk to tropical rainforest ecosystems of drought. Conducting a large-scale long-term drought experiment in a model rainforest ecosystem (Biosphere 2 WALD project), we evaluated the role of plant physiological responses, above and below ground, in response to drought and subsequent recovery in five species (3 canopy species, 2 understory species). The model rainforest was exposed to a 9.5-week lasting drought. Severe drought was ended with a deep water pulse strongly enriched in <sup>2</sup>H, which allowed us to distinguish between deep and shallow rooting plants, and subsequent rain (natural abundance range of <sup>2</sup>H). We assessed plant physiological responses by leaf water potential, sap flow and high resolution monitoring of leaf gas exchange (concentrations and stable isotopes of H<sub>2</sub>O and CO<sub>2</sub>). Thereby, we could derive plant water uptake and leaf water use efficiency (WUE<sub>leaf</sub>) in high temporal resolution, revealing short-term and long-term responses of plant individuals to drought and rewetting. The observed water use strategies of species and plants differed widely. No uniform response in assimilation (A) and transpiration (T) to drought was found for species, resulting in decreasing, relatively constant, or increasing WUE<sub>leaf</sub> across plant individuals. While WUE<sub>leaf</sub> of some plant individuals strongly decreased due to a breakdown in A, others maintained relatively high T and A and thus constant WUE<sub>leaf, </sub>or increased WUE<sub>leaf</sub> by decreasing T while keeping A relatively high. We expect that the observed plant-specific responses in A, T and WUE<sub>leaf</sub> were strongly related to the plant individuals' access to soil water. We assume that plant individuals with constant WUE<sub>leaf</sub> could maintain their leaf gas exchange due to access to water of deeper soil layers, while plants with increasing/decreasing WUE<sub>leaf</sub> mainly depended on shallow soil water and only had limited or no access to deep soil water. We conclude that the observed physiological responses to drought were not only determined by species-specific water use strategies but also by the diverse strategies within species, mainly depending on the plant individuals' size and place of location. Our results highlight the plasticity of water use strategies beyond species-specific strategies and emphasize its importance for species’ survival in face of climate change and increasing drought.</p>

scholarly journals Primed Acclimation of Papaya Increases Short-term Water Use But Does Not Confer Long-term Drought Tolerance

HortScience ◽  
2017 ◽  
Vol 52 (3) ◽  
pp. 441-449 ◽  
Author(s):  
Christopher Vincent ◽  
Diane Rowland ◽  
Bruce Schaffer
Keyword(s):  
Drought Stress ◽  
Soil Water ◽  
Water Deficit ◽  
Water Use ◽  
Dry Matter ◽  
Leaf Gas Exchange ◽  
Severe Drought ◽  
Dry Matter Accumulation ◽  
Short Term ◽  
Soil Water Tension

Primed acclimation (PA) is a regulated deficit irrigation (RDI) strategy designed to improve or maintain yield under subsequent drought stress. A previous study showed photosynthetic increases in papaya in response to a PA treatment. The present study was undertaken to test the duration of the PA effect when papaya plants were challenged with severe drought stress. Potted plants were stressed at 1, 2, and 3 months after conclusion of a PA treatment consisting of 3 weeks at soil water tension (SWT) of −20 kPa. Measurements included leaf gas exchange, root growth, and organ dry mass partitioning. PA did not reduce net CO2 assimilation (A) during the deficit period. At the end of the PA period, total dry matter accumulation per plant and for each organ was unaffected, but proportional dry matter partitioning to roots was favored. After resuming full irrigation, A increased and whole plant water use was more than doubled in PA-treated plants. However, water use and A of PA-treated plants decreased to reconverge with those of control plants by 6 weeks after the PA treatment. Over the course of the study, PA plants maintained lower stem height to stem diameter ratios, and shorter internode lengths. However, these changes did not improve photosynthetic response to any of the water-deficit treatments. We conclude that papaya exhibits some signs of stress memory, but that rapid short-term acclimation responses dominate papaya responses to soil water deficit.

scholarly journals Water status and gas exchange of umbu plants (Spondias tuberosa Arr. Cam.) propagated by seeds and stem cuttings

2007 ◽  
Vol 29 (2) ◽  
pp. 355-358 ◽  
Author(s):  
José Moacir Pinheiro Lima Filho
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Water Potential ◽  
Soil Water ◽  
Water Deficit ◽  
Leaf Water Potential ◽  
Leaf Gas Exchange ◽  
Leaf Water ◽  
Soil Water Deficit ◽  
Stem Cuttings

The experiment was carried out at the Embrapa Semi-Árido, Petrolina-PE, Brazil, in order to study the physiological responses of umbu plants propagated by seeds and by stem cuttings under water stress conditions, based on leaf water potential and gas exchange measurements. Data were collected in one-year plants established in pots containing 30 kg of a sandy soil and submitted to twenty-day progressive soil water deficit. The evaluations were based on leaf water potential and gas exchange data collection using psychrometric chambers and a portable infra-red gas analyzer, respectively. Plants propagated by seeds maintained a significantly higher water potential, stomatal conductance, transpiration and photosynthesis under decreasing soil water availability. However, plants propagated by stem cuttings were unable to maintain a favorable internal water balance, reflecting negatively on stomatal conductance and leaf gas exchange. This fact is probably because umbu plants propagated by stem cuttings are not prone to formation of root tubers which are reservoirs for water and solutes. Thus, the establishing of umbu plants propagated by stem cuttings must be avoided in areas subjected to soil water deficit.

scholarly journals Grafting cv. Grechetto Gentile Vines to New M4 Rootstock Improves Leaf Gas Exchange and Water Status as Compared to Commercial 1103P Rootstock

Agronomy ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 708 ◽  
Author(s):  
Tommaso Frioni ◽  
Arianna Biagioni ◽  
Cecilia Squeri ◽  
Sergio Tombesi ◽  
Matteo Gatti ◽  
...  
Keyword(s):  
Water Stress ◽  
Gas Exchange ◽  
Water Use ◽  
Leaf Gas Exchange ◽  
Water Status ◽  
Stomatal Closure ◽  
Leaf Water ◽  
Summer Drought ◽  
Co2 Uptake ◽  
Drought Tolerant

M4 is a relatively new rootstock that was selected for increased resilience of vineyards across hot regions where meteorological drought is often coupled to water scarcity. However, M4 has thus far been tested only against water-stress sensitive rootstocks. Against this backdrop, the aim of the present work is to examine the water status and gas exchange performances of vines grafted to M4 in comparison to those of vines grafted to a commercial stock that is drought-tolerant, 1103 Paulsen (1103P), under a progressive water deficit followed by re-watering. This study was undertaken on Grechetto Gentile, a cultivar that is renowned for its rather conservative water use (near-isohydric behavior). While fifty percent of both grafts were fully irrigated (WW), the remaining underwent progressive water stress by means of suspending irrigation (WS). Soil and leaf water status, as well as leaf gas exchanges, along with chlorophyll fluorescence, were followed daily from 1 day pre-stress (DOY 176) until re-watering (DOY 184). Final leaf area per vine, divided in main and lateral contribution, was also assessed. While 1103P grafted vines manifested higher water use under WW conditions, progressive stress evidenced a faster water depletion by 1103P, which also maintained slightly more negative midday leaf water potential (Ψleaf) as compared to M4 grafted plants. Daily gas exchange readings, as well as diurnal assessment performed at the peak of stress (DOY 183), also showed increased leaf assimilation rates (A) and water use efficiency (WUE) in vines grafted on M4, which were also less susceptible to photosynthetic downregulation. Dynamic of stomatal closure targeted at 90% reduction of leaf stomatal conductance showed a similar behavior among rootstocks since the above threshold was reached by both at Ψleaf of about −1.11 MPa. The same fractional reduction in leaf A was reached by vines grafted on M4 at a Ψleaf of −1.28 MPa vs. −1.10 MPa measured in 1103P, meaning that using M4 as a rootstock will postpone full stomatal closure. While mechanisms involved in improved CO2 uptake in M4-grafted vines under moderate-to-severe stress are still unclear, our data support the hypothesis that M4 might outscore the performance of a commercial drought-tolerant genotype (1103P) and can be profitably used as a tool to improve the resilience of vines to summer drought.

scholarly journals Leaf Gas Exchange, Plant Water Relations and Water Use Efficiency of Vigna Unguiculata L. Walp. Inoculated with Rhizobia under Different Soil Water Regimes

Water ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 498 ◽  
Author(s):  
Moussa Tankari ◽  
Chao Wang ◽  
Ximei Zhang ◽  
Li Li ◽  
Rajesh Soothar ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Water Use Efficiency ◽  
Soil Water ◽  
Water Use ◽  
Vigna Unguiculata ◽  
Leaf Gas Exchange ◽  
Plant Water ◽  
Water Regimes ◽  
Use Efficiency ◽  
Δ13c And Δ18o

Impact of soil water regimes on physiological responses and water use efficiency (WUE) for Vigna unguiculata L. Walp. (cowpea) inoculated with rhizobia still remains implicit. Therefore, the goal of the current study was to examine the leaf gas exchange, abscisic acid (ABA) and hydraulic signaling, WUE and carbon and oxygen isotopic compositions (δ13C and δ18O) of cowpea under different soil water levels. The treatments included soil water regimes at three levels (90%, 70%, and 50% of soil water holding capacity (SWHC)) and two inoculation forms (inoculated and non-inoculated with rhizobia). The results showed that across the inoculation treatments, reduced soil water regimes depressed both stomatal conductance (gs) and photosynthesis (An) of the leaves, nonetheless, the decrease of gs was more pronounced compared with the reduction in An. Consequently, the intrinsic water use efficiency (WUEi) was improved in the treatments under decreased soil water conditions. Plant WUE was also improved when soil water contents decreased as exemplified by the increased leaf δ13C and δ18O, indicating the enhanced plant WUE was mainly attributed to the decrease of gs. Significant interactions between soil water regimes and rhizobia treatments for root water potential (RWP), leaf water potential (LWP), and gs were found due to the different responses of rhizobia to varied soil water regimes. Inoculation could improve plant water status and gs under 70% and 90% SWHC compared to 50% SWHC with negative effect from rhizobia. A moderate soil water regime is suggested for cowpea production in terms of high WUE with a minor biomass reduction.

scholarly journals Stomatal behavior of different grapevine cultivars in response to soil water status and air water vapor pressure deficit

OENO One ◽  
2010 ◽  
Vol 44 (1) ◽  
pp. 9 ◽  
Author(s):  
Jorge A. Prieto ◽  
Éric Lebon ◽  
Hernán Ojeda
Keyword(s):  
Water Vapor ◽  
Gas Exchange ◽  
Soil Water ◽  
Vapor Pressure Deficit ◽  
Leaf Gas Exchange ◽  
Water Status ◽  
Water Vapor Pressure ◽  
Leaf Water ◽  
Stomatal Response ◽  
Water Vapor Pressure Deficit

<p style="text-align: justify;"><strong>Aims</strong>: Genetic variability in grapevine cultivars may influence their strategy to cope with drought through stomatal regulation of transpiration rate. The aim of the present study was to evaluate the stomatal sensitivity of five cultivars (Ekigaïna, Grenache, Marselan, Mourvèdre, and Syrah) to soil water status and air water vapor pressure deficit (VPD).</p><p style="text-align: justify;"><strong>Methods and results</strong>: Leaf gas exchange and canopy light interception efficiency (ε<sub>i</sub>) were evaluated through a wide range of predawn leaf water potential (Ψ<sub>PD</sub>) measurements in a field experiment in Southern France. Additionally, greenhouse experiments were carried out to monitor stomatal response to increasing VPD levels. Ekigaïna showed a strong isohydric behavior with the highest decrease in leaf gas exchange in response to soil water stress and VPD. Mourvèdre and Grenache showed a similar but relatively less extreme behavior. These three cultivars showed a constant leaf water status during the day through stomatal regulation and a strong decrease in ε<sub>i</sub>. In contrast, Syrah and Marselan displayed anisohydric behavior as they presented a less sensitive stomatal control. Both cultivars showed fluctuating midday leaf water potential and Marselan was the least affected in terms of ε<sub>i</sub>.</p><p style="text-align: justify;"><strong>Conclusion</strong>: This study demonstrated that grape cultivars differed in their stomatal response to soil water deficit and VPD. For a given cultivar, a similar stomatal behavior was found in response to both Ψ<sub>PD</sub> and VPD.</p><p style="text-align: justify;"><strong>Significance and impact of the results</strong>: Adaptation to drought and viticulture viability in hot and dry environments could be achieved by identifying and breeding cultivars with drought tolerance traits.</p>

Long-term liming improves soil fertility and soybean root growth, reflecting improvements in leaf gas exchange and grain yield

2021 ◽  
Vol 128 ◽  
pp. 126308
Author(s):  
João William Bossolani ◽  
Carlos Alexandre Costa Crusciol ◽  
José Roberto Portugal ◽  
Luiz Gustavo Moretti ◽  
Ariani Garcia ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Root Growth ◽  
Soil Fertility ◽  
Grain Yield ◽  
Leaf Gas Exchange ◽  
Soybean Root

Growth and leaf gas exchange in Populus euphratica across soil water and salinity gradients

2013 ◽  
Vol 51 (3) ◽  
pp. 321-329 ◽  
Author(s):  
J. Y. Li ◽  
C. Y. Zhao ◽  
J. Li ◽  
Y. Y. Yan ◽  
B. Yu ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Soil Water ◽  
Leaf Gas Exchange ◽  
Populus Euphratica ◽  
Salinity Gradients

scholarly journals Water Deficit Modulates the CO2 Fertilization Effect on Plant Gas Exchange and Leaf-Level Water Use Efficiency: A Meta-Analysis

2021 ◽  
Vol 12 ◽  
Author(s):  
Fei Li ◽  
Dagang Guo ◽  
Xiaodong Gao ◽  
Xining Zhao
Keyword(s):  
Gas Exchange ◽  
Water Use Efficiency ◽  
Soil Water ◽  
Water Deficit ◽  
Water Use ◽  
Future Climate Change ◽  
Leaf Level ◽  
Fertilization Effect ◽  
Use Efficiency ◽  
Stimulation Of

Elevated atmospheric CO2 concentrations ([eCO2]) and soil water deficits significantly influence gas exchange in plant leaves, affecting the carbon-water cycle in terrestrial ecosystems. However, it remains unclear how the soil water deficit modulates the plant CO2 fertilization effect, especially for gas exchange and leaf-level water use efficiency (WUE). Here, we synthesized a comprehensive dataset including 554 observations from 54 individual studies and quantified the responses for leaf gas exchange induced by e[CO2] under water deficit. Moreover, we investigated the contribution of plant net photosynthesis rate (Pn) and transpiration rates (Tr) toward WUE in water deficit conditions and e[CO2] using graphical vector analysis (GVA). In summary, e[CO2] significantly increased Pn and WUE by 11.9 and 29.3% under well-watered conditions, respectively, whereas the interaction of water deficit and e[CO2] slightly decreased Pn by 8.3%. Plants grown under light in an open environment were stimulated to a greater degree compared with plants grown under a lamp in a closed environment. Meanwhile, water deficit reduced Pn by 40.5 and 37.8%, while increasing WUE by 24.5 and 21.5% under ambient CO2 concentration (a[CO2]) and e[CO2], respectively. The e[CO2]-induced stimulation of WUE was attributed to the common effect of Pn and Tr, whereas a water deficit induced increase in WUE was linked to the decrease in Tr. These results suggested that water deficit lowered the stimulation of e[CO2] induced in plants. Therefore, fumigation conditions that closely mimic field conditions and multi-factorial experiments such as water availability are needed to predict the response of plants to future climate change.

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