Understanding How Plants Respond to Drought Stress at the Molecular and Whole Plant Levels

2016 ◽  
pp. 1-37 ◽  
Author(s):  
Nezar H. Samarah
Keyword(s):  
Drought Stress ◽  
Whole Plant

Sucrose Transporter Gene AtSUC4 Responds to Drought Stress by Regulating the Sucrose Distribution and Metabolism in Arabidopsis thaliana

2013 ◽  
Vol 765-767 ◽  
pp. 2971-2975 ◽  
Author(s):  
Xue Gong ◽  
Ming Li Liu ◽  
Li Jun Zhang ◽  
Wei Liu ◽  
Che Wang
Keyword(s):  
Arabidopsis Thaliana ◽  
Drought Stress ◽  
Plant Stress ◽  
Homozygous Mutation ◽  
Transporter Gene ◽  
Wild Type ◽  
Sucrose Transporters ◽  
Whole Plant ◽  
Plant Stress Tolerance ◽  
Plant Level

Sucrose transporters (SUCs or SUTs) are considered as the important carriers and responsible for the loading, unloading and distribution of sucrose, but at present there is no report that SUCs are involved in sucrose distribution and metabolism under drought stress at the whole-plant level. AtSUC4, as the unique member of SUT4-clade inArabidopsis thaliana, may be important for plant stress tolerance. Here, by analyzing two homozygous mutation lines ofAtSUC4(Atsuc4-1andAtsuc4-2), we found drought stress induced higher sucrose, lower fructose and glucose contents in shoots, and lower sucrose, higher fructose and glucose contents in roots of these mutants compared with the wild-type (WT), leading to an imbalance of sucrose distribution, fructose and glucose (sucrose metabolites) accumulation changes at the whole-plant level. Thus we believe thatAtSUC4regulates sucrose distribution and metabolism in response to drought stress.

scholarly journals Mechanisms of xylem hydraulic recovery after drought in Eucalyptus saligna

2021 ◽  
Author(s):  
Alice Gauthey ◽  
Jennifer Peters ◽  
Rosana López ◽  
Madeline Carins Murphy ◽  
Celia M. Rodriguez-Dominguez ◽  
...  
Keyword(s):  
Drought Stress ◽  
Severe Drought ◽  
Stem Water Potential ◽  
Micro Computed Tomography ◽  
Time Intervals ◽  
Eucalyptus Saligna ◽  
Whole Plant ◽  
Xylem Tissue ◽  
Stem Water

The mechanisms by which woody plants recover xylem hydraulic capacity after drought stress are not well understood, particularly with regard to the role of embolism refilling. We evaluated the recovery of xylem hydraulic capacity in young Eucalyptus saligna plants exposed to cycles of drought stress and rewatering. Plants were exposed to moderate and severe drought stress treatments, with recovery monitored at time intervals from 24 hrs to 6 months after rewatering. The percentage loss of xylem vessels due to embolism (PLV) was quantified at each time point using micro-computed tomography with stem water potential (Ψx) and whole plant transpiration (Eplant) measured prior to scans. Plants exposed to severe drought stress suffered high levels of embolism (47.38 ± 10.97 % PLV) and almost complete canopy loss. No evidence of embolism refilling was observed at 24 hrs, one week, or three weeks after rewatering despite rapid recovery in Ψx. Recovery of hydraulic capacity was achieved over a 6-month period by growth of new xylem tissue, with canopy leaf area and Eplant recovering over the same period. These findings indicate that E. saligna recovers slowly from severe drought stress, with potential for embolism to persist in the xylem for many months after rainfall.

Main effects of nitrogen supply and drought stress upon whole-plant carbon allocation in poplar

1997 ◽  
Vol 27 (9) ◽  
pp. 1413-1419 ◽  
Author(s):  
L Ibrahim ◽  
M F Proe ◽  
A D Cameron
Keyword(s):  
Drought Stress ◽  
Carbon Allocation ◽  
Nitrogen Supply ◽  
Whole Plant ◽  
Main Effects

Die and let live: leaf senescence contributes to plant survival under drought stress

2004 ◽  
Vol 31 (3) ◽  
pp. 203 ◽  
Author(s):  
Sergi Munné-Bosch ◽  
Leonor Alegre
Keyword(s):  
Drought Stress ◽  
Leaf Senescence ◽  
Chromatin Condensation ◽  
Cell Ultrastructure ◽  
Climatic Conditions ◽  
Oxygen Species ◽  
Plant Survival ◽  
Whole Plant ◽  
Leaf Yellowing

Leaf senescence is a highly regulated physiological process that leads to leaf death and is, as such, the last developmental stage of the leaf. Plant aging and environmental stresses may induce the process of senescence. Here we will focus on the role of leaf senescence in field-grown plants as a response to adverse climatic conditions and, more specifically, on how it contributes to plant survival under drought stress. Drought induces several responses in plants including leaf senescence, which plays a major role in the survival of several species. Drought-induced leaf senescence contributes to nutrient remobilisation during stress, thus allowing the rest of the plant (i.e. the youngest leaves, fruits or flowers) to benefit from the nutrients accumulated during the life span of the leaf. In addition, drought-induced leaf senescence, especially when accompanied by leaf abscission, avoids large losses through transpiration, thus contributing to the maintenance of a favourable water balance of the whole plant. Drought-induced leaf senescence occurs gradually and is characterised by specific macroscopic, cellular, biochemical and molecular changes. Leaf yellowing (i.e. chlorophyll degradation) and specific changes in cell ultrastructure (e.g. chromatin condensation, thylakoid swelling, plastoglobuli accumulation), metabolism (e.g.�protein degradation, lipid peroxidation) and gene expression occur during leaf senescence in drought-stressed plants. Cytokinins and ABA have been shown to be involved in the regulation of drought-induced leaf senescence, although the possible role of other plant hormones should not be excluded. Reactive oxygen species, whose concentrations increase during drought-induced leaf senescence, are also known to be regulators of this process. The complex mechanisms of regulation of leaf senescence in drought-stressed plants are discussed, and attention is drawn to those aspects that still require investigation.

scholarly journals Whole-plant Photosynthesis of Containerized Hydrangeas and Abelias as Affected by Substrate Moisture Content

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1111D-1111 ◽  
Author(s):  
Marc W. van Iersel ◽  
Sue Dove
Keyword(s):  
Growth Rate ◽  
Drought Stress ◽  
Moisture Content ◽  
Water Potential ◽  
Photosynthetic Rate ◽  
Severe Drought ◽  
Whole Plant ◽  
Growing Medium ◽  
Plant Photosynthesis ◽  
Substrate Moisture

Efficient water use in nurseries is increasingly important. In recent years, new soil moisture sensors (ECH2O probes) have become available, making it possible to monitor the moisture content of the growing medium in containers. One piece of information that is lacking for fully-automated irrigation systems is how much water actually needs to be present in the growing medium to prevent detrimental effects of drought on plants. We determined the effect of substrate moisture on photosynthesis and plant water relations of hydrangea and abelia. Growth rates of these species were measured during two subsequent drying cycles to determine how drought affects the growth rate of these species. Whole-plant photosynthesis, an indicator of growth rate, of both species remained stable as the volumetric moisture content of the substrate dropped from 25% to 15%, with pronounced decreases in photosynthesis at lower substrate moisture levels. Abelias and hydrangeas wilted when the substrate moisture level dropped to 6.3% and 8.3%, respectively. At wilting, abelias had lower leaf water potential (–3.7 MPa) than hydrangeas (–1.8 MPa). After the plants were watered at the end of the first drying cycle, the photosynthesis of the plants did not recover to pre-stress rates, indicating that the drought stress caused a long-term reduction in photosynthesis. Despite the more severe drought stress in the abelias (both a lower substrate water content and lower water potential at wilting), abelias recovered better from drought than hydrangeas. After the plants were watered at the end of the first drying cycle, the photosynthetic rate of abelias recovered to ≈70%, while the photosynthetic rate of the hydrangeas recovered to only 62% of the pre-stress rate.

scholarly journals Relating Whole-plant Photosynthesis to Physiological Acclimations at Leaf and Cellular Scales under Drought Stress in Bedding Plants

2019 ◽  
Vol 144 (3) ◽  
pp. 201-208
Author(s):  
Krishna Nemali ◽  
Marc W. van Iersel
Keyword(s):  
Drought Stress ◽  
Net Photosynthesis ◽  
Carbon Gain ◽  
Bedding Plants ◽  
Drought Tolerant ◽  
Whole Plant ◽  
Increased Risk ◽  
Bedding Plant ◽  
Drought Conditions ◽  
Plant Photosynthesis

Bedding plants are at increased risk for exposure to drought stress during production because they are grown in small containers. Physiological mechanisms of bedding plants at leaf and cellular scales that regulate whole-plant photosynthesis under drought conditions are not well understood. This information can be useful for screening bedding plant cultivars with improved drought-tolerance and generate guidelines to mitigate drought stress during production. We subjected drought-sensitive salvia (Salvia splendens ‘Bonfire Red’) and drought-tolerant vinca (Catharanthus roseus ‘Cooler Peppermint’) to gradual drought stress inside whole-plant gas exchange chambers. Substrate water content (Θ), whole-plant net photosynthesis (Pn_avg), whole-plant respiration (Rd_avg), and daily carbon gain (DCG) were measured continuously, whereas stomatal conductance (gS) to water, leaf water (ΨL), osmotic (ΨS), and turgor (ΨP) potentials were measured at the start and end of the drought phase. In addition, ΨS was measured before exposure to stress and after thoroughly rehydrating plants. Dark-adapted quantum efficiency (dark-adapted ΦPSII) was measured after rehydrating plants. The results indicated that, at whole-plant scale, vinca continued to uptake water at lower Θ levels than the Θ level that resulted in wilting of salvia. There were no differences in Rd_avg; however, Pn_avg and DCG of salvia decreased at a higher Θ level than that of vinca. This indicated that salvia experienced drought stress at a higher Θ level than did vinca. At the leaf scale, there were no differences in ΨL; however, a more negative ΨS (P = 0.06) and significantly higher ΨP were observed in vinca (compared to salvia) under drought conditions. In addition, ΨS was not different between species before exposure to drought, whereas ΨS of rehydrated leaves after exposure to drought in vinca was significantly lower than that in salvia. Moreover, ΨS of rehydrated leaves after exposure to drought was significantly lower than that observed before exposure to drought in vinca. This indicated osmotic adjustment (OA) in vinca under drought conditions. Dark-adapted ΦPSII was lower in salvia than in vinca after exposure to drought, indicating damage to photosynthetic mechanisms. Our results suggested that increased OA likely helped to maintain higher ΨP under drought conditions and continuation of water uptake at lower Θ in vinca compared to salvia. In addition, healthier photosynthetic mechanisms of vinca (compared to salvia) under drought conditions likely resulted in its higher Pn_avg and DCG at lower Θ. Screening for OA and dark-adapted ΦPSII may be useful for developing drought-tolerant bedding plant cultivars.

Whole-plant hydraulic conductance and root-to-shoot flow of abscisic acid are independently affected by water stress in grapevines

2002 ◽  
Vol 29 (11) ◽  
pp. 1349 ◽  
Author(s):  
Claudio Lovisolo ◽  
Wolfram Hartung ◽  
Andrea Schubert
Keyword(s):  
Water Stress ◽  
Drought Stress ◽  
Shoot Growth ◽  
Leaf Growth ◽  
Hydraulic Conductance ◽  
Hydraulic Limitation ◽  
Whole Plant ◽  
Stem Water ◽  
Stress Experiment ◽  
Rooted Shoot

In order to investigate whether plant hydraulic conductance (gplant) is reduced under drought conditions via an ABA-related mechanism, a water-stress experiment was carried out using split-rooted grapevines. In addition, inversion of shoot growth orientation was imposed to reduce gplant independently of soil water availability, and thus of the putative ABA root-generated stress message. As expected, water stress imposed on split-roots affected ABA accumulation. ABA drought-stress message negatively affected stomatal conductance (gs) and transpiration (E), but modified neither leaf or stem water potentials (Ψleaf and Ψstem, respectively), nor gplant. When gplant was reduced in split-rooted, shoot-inverted (s-r/s-i) grapevines, Ψleaf and Ψstem decreased, without changes in ABA accumulation, gs and E. The ABA drought-stress message did not modify gplant, nor did gplant (impaired by shoot-growth inversion) decrease ABA delivery to the leaves. However, leaf growth was depressed in s-r/s-i grapevines. The fact that no interaction between ABA stress messages (caused by split-root technique) and hydraulic constraints to sap flow (caused by shoot inversion) was necessary to impair leaf growth suggests that the targets of ABA and hydraulic-limitation effects on leaf expansion are not the same.

Whole-plant water hydraulic integrity to predict drought-induced Eucalyptus urophylla mortality under drought stress

2020 ◽  
Vol 468 ◽  
pp. 118179 ◽  
Author(s):  
Xia Chen ◽  
Ping Zhao ◽  
Lei Ouyang ◽  
Liwei Zhu ◽  
Guangyan Ni ◽  
...  
Keyword(s):  
Drought Stress ◽  
Plant Water ◽  
Eucalyptus Urophylla ◽  
Whole Plant ◽  
Water Hydraulic

scholarly journals Sorghum’s Whole-Plant Transcriptome and Proteome Responses to Drought Stress: A Review

Life ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 704
Author(s):  
Rudo Ngara ◽  
Tatenda Goche ◽  
Dirk Z. H. Swanevelder ◽  
Stephen Chivasa
Keyword(s):  
Drought Stress ◽  
Metabolic Pathways ◽  
Agronomic Traits ◽  
Primary Role ◽  
Cereal Crop ◽  
Whole Plant ◽  
Functional Classes ◽  
Plant Transcriptome ◽  
Heat Stress Tolerance ◽  
Drought And Heat Stress

Sorghum is a cereal crop with key agronomic traits of drought and heat stress tolerance, making it an ideal food and industrial commodity for hotter and more arid climates. These stress tolerances also present a useful scientific resource for studying the molecular basis for environmental resilience. Here we provide an extensive review of current transcriptome and proteome works conducted with laboratory, greenhouse, or field-grown sorghum plants exposed to drought, osmotic stress, or treated with the drought stress-regulatory phytohormone, abscisic acid. Large datasets from these studies reveal changes in gene/protein expression across diverse signaling and metabolic pathways. Together, the emerging patterns from these datasets reveal that the overall functional classes of stress-responsive genes/proteins within sorghum are similar to those observed in equivalent studies of other drought-sensitive model species. This highlights a monumental challenge of distinguishing key regulatory genes/proteins, with a primary role in sorghum adaptation to drought, from genes/proteins that change in expression because of stress. Finally, we discuss possible options for taking the research forward. Successful exploitation of sorghum research for implementation in other crops may be critical in establishing climate-resilient agriculture for future food security.

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