SEARCH · PubMed Health

Results for “Droughts”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 289 records · Page 16Linked to original sources

PubMed2003

CBL1, a calcium sensor that differentially regulates salt, drought, and cold responses in Arabidopsis.

Although calcium is a critical component in the signal transduction pathways that lead to stress gene expression in higher plants, little is known about the molecular mechanism underlying calcium function. It is believed that cellular calcium changes are perceived by sensor molecules, including calcium binding proteins. The calcineurin B-like (CBL) protein family represents a unique group of calcium sensors in plants. A member of the family, CBL1, is highly inducible by multiple stress signals, implicating CBL1 in stress response pathways. When the CBL1 protein level was increased in transgenic Arabidopsis plants, it altered the stress response pathways in these plants. Although drought-induced gene expression was enhanced, gene induction by cold was inhibited. In addition, CBL1-overexpressing plants showed enhanced tolerance to salt and drought but reduced tolerance to freezing. By contrast, cbl1 null mutant plants showed enhanced cold induction and reduced drought induction of stress genes. The mutant plants displayed less tolerance to salt and drought but enhanced tolerance to freezing. These studies suggest that CBL1 functions as a positive regulator of salt and drought responses and a negative regulator of cold response in plants.

Arabidopsis↗

PubMed1995

ENSO and disaster: droughts, floods and El Niño/Southern Oscillation warm events.

The connection between El Niño/Southern Oscillation (ENSO) events and precipitation and temperature variability worldwide is increasingly well understood. ENSO has been linked to droughts and flooding in some regions. This paper uses the disaster history database of the U.S. Agency for International Development's Office of U.S. Foreign Disaster Assistance to examine the link between ENSO events and droughts or floods of sufficient magnitude to trigger international disasters. Worldwide, disasters triggered by droughts are twice as frequent during year two of ENSO warm events than during other years. No such relationship is apparent in the case of flood disasters. Drought disasters occur during year two of ENSO warm events significantly more frequently than in other years in Southern Africa and Southeast Asia. No regional pattern emerges from a comparable analysis of flood disasters. Those places likely to be affected by ENSO-triggered droughts can take proactive measures to mitigate the impacts.

Atmosphere↗

PubMed1995

Structural adjustment and drought in Zambia.

While drought is not uncommon in Zambia, the country is now facing the worst drought in history. The monetary and social costs will be enormous. Although it is too early to measure the economic and social costs of the drought on Zambia, it is obvious that the impact is catastrophic on a country whose economy is under pressure. The drought will affect the structural adjustment programme (SAP) unveiled by the new government which has embraced the market economy. The country has imported, and will continue to import, large quantities of maize and other foodstuffs, a situation likely to strain the balance of payments. Earlier targets with regard to export earnings, reductions in the budget deficit, and GDP growth as contained in the Policy Framework Paper (PFP) are no longer attainable due to the effects of the drought.

Disasters↗

PubMed1996

Immunogold localization and quantification of cellular and subcellular abscisic acid, prior to and during drought stress.

An immunogold labeling procedure and experimental data are presented, which demonstrate that antibodies produced against a bovine serum albumin-abscisic acid conjugate can be used both to characterize the cellular and subcellular localization of abscisic acid (ABA), and to permit quantitative comparisons of this hormone in the subcellular compartments prior to and at times of drought stress. At the control leaf water potential (approximately -0.45 MPa), a quantitatively similar positive labeling pattern was observed in the chloroplasts and apoplast. A twofold drought stress-induced increase in the apoplastic ABA concentration was observed in the drought stressed leaf tissue (i.e., at a leaf water potential of approximately -1.55 MPa), while the ABA concentration in the chloroplasts did not differ from that of the controls. Three histochemical controls and the physiological observations validated the specificity of the procedure. Based on the labeling patterns we observed and literature cited, the validity of the hypothesis that drought stress induces a release of chloroplastic ABA is questioned. We interpreted our results as providing indirect evidence for a drought stress-induced root source origin for the increased apoplastic ABA concentrations.

Abscisic Acid↗

PubMed2001

Drought stress, plant water status, and floral trait expression in fireweed, Epilobium angustifolium (Onagraceae).

In a controlled environment, we artificially induced drought during flowering of Epilobium angustifolium, an animal-pollinated plant. Leaf water potential (ψ(l)) and floral traits were monitored over a 12-d period of soil moisture depletion. Soil moisture depletion induced drought stress over time, as revealed by significant treatment × day interactions for predawn and midday ψ(l). Nectar volume and flower size showed significant negative responses to drought stress, but nectar sugar concentration did not vary between treatments. Floral traits were more buffered from drought than leaf water potentials. We used path analysis to examine direct and indirect effects of ψ(l) on floral traits for plants in well-watered (control) vs. drought treatments. According to the best-fit path models, midday ψ(l) has significant positive effects on flower size and nectar volume in both environments. However, for controls midday ψ(l) also had a significant negative effect on nectar sugar concentration. Results indicate that traits influencing floral attractiveness to pollinators in E. angustifolium vary with plant water status, such that pollinator-mediated selection could indirectly target physiological or biochemical controls on ψ(l). Moreover, under mesic conditions selection for greater nectar sugar reward may be constrained by the antagonistic effects of plant water status on nectar volume and sugar concentration.

Journal Article↗

PubMed2002

[Effect of drought stress on apparent resource utilization efficiency of Quercus mongolica].

To study the effect of drought stress on the physiological characteristics and resource utilization efficiency of Quercus mongolica, a dominant species in the Korean pine broad-leaved forest in Changbai Mountain, a comparative experiment was carried out under three soil moisture gradients as 85%-100% (high water, CK), 65%-85% (Medium water, MW), and 45%-65% (low water, LW) of field water-bolding capacity. The results showed that net photosynthetic rate, stomatal conduction, transpiration rate, water utilization efficiency, apparent CO2 utilization efficiency and apparent light utilization efficiency of the seedlings of Quercus mongolica were all significantly influenced by simulated drought stress. Stomatal conduction, water utilization efficiency and net photosynthetic rate of large tress of Quercus mongolica were affected by the soil drought stress, while transpiration rate, apparent CO2 utilization efficiency, and apparent light utilization efficiency were not influenced. Moderate soil water condition could greatly increase gas exchange and water utilization efficiency. These results indicated that the responses of gas exchange and resource utilization efficiency to various water stresses were different. Quercus mongolica was a species with variable resistance to drought stress, and the resistance would be improved by drought stress, especially moderate water stress.

Carbon Dioxide↗

PubMed2002

[Analysis of gene loci and epistasis for drought tolerance in seedling stage of rice (Oryza sativa L.)].

Drought tolerance of rice is important because a considerable proportion of the world rice area is not irrigated and is prone to water deficit. In this study, an indica variety, Zhai Ye Qing 8 (ZYQ8), and a japonica variety, Jing Xi 17 (JX17), and their double haploid (DH) population were used for genetic study of drought tolerance. Water supply was stopped in seedling period for 15 days and then drought tolerance of the DH population and their parents were investigated. Mapping quantitative trait loci (QTLs) was undertaken base on the constructed molecular linkage map of this population. Two QTLs (qDR-5 and qDR-12) for drought tolerance were identified, they were in the region of GA41-GA257 on chromosome 5 and RG457-Y12817R on chromosome 12, respectively. The tolerance alleles of both QTLs were from the indica parent, ZYQ8. In the meantime two genes for drought tolerance near GA257 and Y12817R were detected too by using Epistat software, that is in accordance with the result by using Mapmaker/QTL. In addition, three loci (RG541, G318 and G192 on chromosome 1, 4 and 8, respectively) were found interacting with GA257 by Epistat software, while one locus (CT234 on chromosome 3) found interacting with Y12817R were also detected by Epistat software.

Chromosome Mapping↗

PubMed2002

[Physiological response of two divergent Leymus chinensis types to drought stress in the Songnen Plain].

The physiological response of two divergent Leymus chinensis types (grey-green type and yellow-green type) to drought stress was studied by pot experiment. At seedling stage, some physiological indexes of the plants and leaves were measured by taking the divergent types under stress of polyethylene glycol (PEG). Quantitative analyses showed that under drought stress, the electrolyte leakage rate, proline content, water content, fresh weight, and SO(4)2- and NO3- contents of two divergent types varied significantly. According to the simulating results by equation y = a + bx, the b values of electrolyte leakage rate and chlorophyll content were higher in grey-green type than in yellow-green type, and the b value of water content of grey-green type was lower than that of yellow-green type. The proline content of grey-green type was higher than that of yellow-green type. Factor analyses showed that proline was the most important factor of physiological response to drought stress of the two types. The two types of L. chinensis had certain capabilities of drought resistance, but the capability of grey-green type was greater than that of yellow-green type. Therefore, the physiological characteristics of drought resistance were significantly differentiated.

China↗

PubMed2004

[Effect of drought stress on growth of Glycyrrhiza uralensis].

OBJECTIVE: To study the effect of drought stress on the growth of Glycyrrhiza uralensis and its drought resistance characteristic. METHOD: The growth in dicators of G. uralensis including leaf, stem, root and biomass were measured when two-years-old G. uralensis had lived in drought stress soil for 60 days. RESULT: The growth of all organs of G. uralensis was restrained because of drought stress, especially to up ground organs. CONCLUSION: It is obvious that the restraining effect of drought stress on G. uralensis possesses organ speciality. Both yield and quality of G. uralensis will be satisfied when it grows in the soil with relative water content of 50%.

Disasters↗

PubMed2005

[Effects of exogenous nitric oxide on drought-resistance of poplar].

This paper studied the effects of NO donor sodium nitroprusside (SNP) on the photosynthesis and active oxygen-scavenging enzyme activities of poplar leaves under drought stress. The results showed that SNP had a remarkable positive effect on leaf water content. When the SNP level was > 500 micromol.L(-1), no significant difference in leaf water content was found between SNP treatments. SNP could increase photosynthesis rate, photochemical efficiency of PSII (F(v)/F(m)), and ratios of F(m)/F(o) and F(v)/F(o), but the effects decreased with the prolongation of drought stress. The SOD and POD activities of poplar leaves were higher in short time (1 h) drought stress than in longer time (3 h) one. The activity of POD was increased by SNP, while that of SOD was changed little. With increasing SNP level, the POD and SOD activities first increased and then decreased. The NO donor could retard the accumulation of active oxygen through inducing POD and SOD activities, alleviate the effects of drought stress on photosynthesis, and increase the drought-resistance of poplar.

Disasters↗

PubMed2006

[Protective effects and their mechanisms of cobalt on soybean seedling's leaf under drought stress].

This paper studied the effects of cobalt on the polyamine content, reactive oxygen level, anti-oxidative enzyme activity, and cell membrane permeability of soybean seedling's leaf under drought stress, and discussed the mechanisms of these effects. The results showed that under drought stress, cobalt at its concentration of 30 micromol x L(-1) could significantly inhibit the production of ethylene. This concentration of cobalt had no significant effects on the contents of MDA and chlorophyll when the drought stress lasted 0 to approximately 12 days, but significantly restrained the increase of reactive oxygen level, hampered the decline of putrescine, spermidine and spermine contents and anti-oxidative enzyme activities,and thus,inhibited the accumulation of MDA and alleviated the reduction of chlorophyll content when the stress lasted 15 to approximately 21 days. It could be concluded that when soybean seedling's leaf was deeply stressed and damaged under drought stress, cobalt could alleviate the decline of polyamine content and anti-oxidative enzyme activity,and hence, alleviate the increment of reactive oxygen level and cell membrane's damage degree through inhibiting the production of ethylene, and exerted its protective effects on the soybean seedling's leaf under drought stress.

Amine Oxidase (Copper-Containing)↗

PubMed2005

DNA sequence variation and selection of tag single-nucleotide polymorphisms at candidate genes for drought-stress response in Pinus taeda L.

Genetic association studies are rapidly becoming the experimental approach of choice to dissect complex traits, including tolerance to drought stress, which is the most common cause of mortality and yield losses in forest trees. Optimization of association mapping requires knowledge of the patterns of nucleotide diversity and linkage disequilibrium and the selection of suitable polymorphisms for genotyping. Moreover, standard neutrality tests applied to DNA sequence variation data can be used to select candidate genes or amino acid sites that are putatively under selection for association mapping. In this article, we study the pattern of polymorphism of 18 candidate genes for drought-stress response in Pinus taeda L., an important tree crop. Data analyses based on a set of 21 putatively neutral nuclear microsatellites did not show population genetic structure or genomewide departures from neutrality. Candidate genes had moderate average nucleotide diversity at silent sites (pi(sil) = 0.00853), varying 100-fold among single genes. The level of within-gene LD was low, with an average pairwise r2 of 0.30, decaying rapidly from approximately 0.50 to approximately 0.20 at 800 bp. No apparent LD among genes was found. A selective sweep may have occurred at the early-response-to-drought-3 (erd3) gene, although population expansion can also explain our results and evidence for selection was not conclusive. One other gene, ccoaomt-1, a methylating enzyme involved in lignification, showed dimorphism (i.e., two highly divergent haplotype lineages at equal frequency), which is commonly associated with the long-term action of balancing selection. Finally, a set of haplotype-tagging SNPs (htSNPs) was selected. Using htSNPs, a reduction of genotyping effort of approximately 30-40%, while sampling most common allelic variants, can be gained in our ongoing association studies for drought tolerance in pine.

Base Sequence↗

PubMed2026

Genome-Wide Characterization of the ScLOR Gene Family in Wild Tomato Solanum lycopersicoides Reveals ScLOR16 as a Negative Regulator of Cold-and Drought-Stress Tolerance.

The LOR (LURP-one related) gene family encodes proteins containing conserved LOR domains; however, its functions in plant abiotic stress responses remain largely unexplored. In this study, we systematically identified and characterized the LOR gene family in the stress-tolerant wild tomato Solanum lycopersicoides using comprehensive bioinformatic analyses and conducted functional validation of the candidate gene ScLOR16. A total of 19 ScLOR members were identified and classified into eight phylogenetic subgroups. Numerous cis-acting elements associated with responses to abscisic acid (ABA), cold, and drought, including ABRE, LTR, and MBS, were detected in the promoter regions, suggesting that the ScLOR family may be broadly involved in ABA-mediated stress signaling pathways. RT-qPCR analysis revealed that ScLOR16 expression was significantly induced by both cold and drought treatments. Subcellular localization assays demonstrated that ScLOR16 is localized in both the nucleus and cytoplasm. Virus-induced gene silencing (VIGS) was subsequently employed to generate ScLOR16-silenced plants. Following 24 h of cold treatment at 4 °C and four days of drought stress, ScLOR16-silenced seedlings exhibited significantly less severe wilting symptoms than empty-vector controls. Physiological analyses showed that silenced plants exhibited enhanced superoxide dismutase (SOD) and peroxidase (POD) activities, increased proline accumulation, and decreased thiobarbituric acid-reactive substances (TBARS) content. Collectively, these results indicate that reduced ScLOR16 transcript levels are associated with enhanced cold and drought tolerance, accompanied by alterations in antioxidant defense and osmoprotection-related physiological markers. This study yields new insights into the evolution and stress-related functions of the ScLOR family.

LOR gene family↗

PubMed1995

Drought, mortality and social structure.

The social aspects of drought-induced morbidity and mortality in India are analyzed in this study. "As a sample study, mortality trends in Rajasthan State in India in the 1980s were analysed to correlate the increased death rate with the drought of 1987. It is demonstrated that drought-induced malnutrition is the root cause of death. Sociologically, populations are divided into three sections--fragile, resilient and potent--which are differently affected by droughts, the fragile section suffering worst."

Asia↗

PubMed2005

[sdt1, a novel Arabidopsis mutant tolerant to drought and high-salinity stresses].

Among the 20000 independent Arabidopsis activation tagging lines, we screened a novel mutant with high-salinity and drought tolerance, namely sdt1 (high-salinity and drought tolerant 1). sdt1 kept normal growth under drought stress by consecutively withholding water for 26d, while all the wild type wilted to death. Furthermore, the same result was repeated under high-salinity stress when sdtl and wild type were treated with 150 mmol/L NaCl. Seeds germination test on the medium indicated that the response of sdt1 to endogenous or exogenous ABA was reduced as compared with wild type. Under drought stress conditions the rates of water loss of sdt1 rosette leaves were significantly lower than that of wild type. Southern hybridization of sdt1 and the result of high-salinity tolerance genetic analysis showed that two copies of T-DNA were inserted into the two linking sites by shoulder to shoulder.

Abscisic Acid↗

PubMed2026

From stress signaling to yield stability: physiological and molecular mechanisms of wheat resilience to heat and drought stress.

Wheat resilience depends on coordinated signaling, reproductive protection, and source-sink regulation, providing a framework to breed robust trait combinations that stabilize yield under combined heat and drought. Climate change is increasing the frequency and severity of heat and drought events, posing a major threat to wheat productivity, yield stability, and food security. Because these stresses often coincide in the field, their combined effects can impair growth, reproductive development, grain filling, and final yield more severely than either stress alone. Wheat resilience under such conditions depends on coordinated physiological adjustment and molecular regulation that sustain cellular homeostasis, protect reproductive tissues, and preserve yield-related traits. This review synthesizes current knowledge on the physiological and molecular bases of wheat resilience to heat and drought, with emphasis on their combined effects. We discuss major physiological responses, including photosynthetic adjustment, stomatal regulation, canopy cooling, osmotic balance, antioxidant defense, membrane stability, and source-sink coordination. We also examine key regulatory pathways involved in stress perception and adaptation, including calcium and reactive oxygen species signaling, mitogen-activated protein kinase cascades, phytohormonal crosstalk, transcriptional regulation, heat shock proteins, late embryogenesis abundant proteins, and osmoprotective and redox-associated pathways. In addition, we highlight the growing contribution of transcriptomics, proteomics, metabolomics, and phenomics to the identification of candidate genes, biomarkers, and adaptive traits. Finally, we consider how mechanistic insights can be translated into wheat improvement through molecular markers, genomic selection, gene editing, and climate-realistic phenotyping. An integrated understanding of stress signaling and adaptive trait deployment will be essential for developing wheat cultivars with improved resilience and yield stability under future climates.

Triticum↗

PubMed2026

Genome-wide identification of the peanut HD-Zip gene family and AhHDZ15 positively regulating salt and drought stress in heterologously overexpressed Arabidopsis.

Homeodomain-leucine zipper (HD-Zip) transcription factors play important roles in plant growth, development, and abiotic stress responses. However, bioinformatic analyses and functional studies of HD-Zip family in peanut are scarce. In this study, 128 AhHDZ genes were identified and classified into four subfamilies in the phylogenetic analysis. Transcriptomic data and RT-qPCR analysis indicated the expression levels of AhHDZ4 and AhHDZ15 were significantly elevated in response to 12 h of salt stress, while AhHDZ4/15/60/69/126 all showed a progressive increase over time in response to drought stress. AhHDZ15 protein was localized in the nucleus. Under salt and drought stress, the germination rates of AhHDZ15-overexpressing in Arabidopsis were significantly higher than wild-type (WT), and root lengths were also significantly longer than WT. In addition, the SOD, CAT, chlorophyll content, and Relative Leaf Water Content (RLWC) value of leaves in AhHDZ15-overexpressing lines were significantly higher than WT, while the MDA content was significantly lower than WT. The above results indicate that heterologous overexpression of AhHDZ15 enhanced salt and drought tolerance in Arabidopsis. Furthermore, AhHDZ15 could bind to the L1-box element of the AhVNI2 promoter, thereby activating AhVNI2 transcription and enhancing the expression of downstream salt stress-responsive genes. These findings implies a potential function of AhHDZ15 in peanut that requires further validation.

Arabidopsis↗

PubMed2026

Adaptation to seasonal drought in Arabis alpina is linked to the demographic history and climatic changes since the last glacial maximum.

Understanding how species adapt to new environments is a central goal in evolutionary biology, and a topical question in climate change research. Here, we sequenced the genomes of 426 individuals of the perennial, Arctic-alpine herb Arabis alpina to study demography and adaptation, with a focus on populations in Northern Spain, that experience warm and dry summers. Our inference supports a scenario in which A. alpina colonized Northern Spain in a range expansion event that started near the Alps around 216 thousand years ago (kya). During the last glacial episode (115 to 12 kya), this expansion proceeded westward, and effective population sizes were large across Europe, likely due to a larger suitable habitat for A. alpina. These ancient demographic events gave rise to a highly diverged genetic lineage in Northern Spain. In the present interglacial (between 12 kya and present), populations became increasingly fragmented, and lost genetic diversity across Europe. Furthermore, we detected signatures of selection at genes associated with responses to abiotic stress, including drought stress, and regulation of growth, for instance at SC5D and NAC055, which reflects the climatic changes since the last glacial period. Notably, an ancient polymorphism at the gene FRL1 emerged as a candidate for conferring variation in flowering behavior, and for contributing to adaptation to drought. Our study suggests that the combination of ancestral variation in flowering behavior, and positive selection on new mutations involved in drought responses, underlies the evolution of a new trait syndrome, and adaptation to climate change.

Droughts↗