Revealing the Effects of Potassium on Rice Roots under Moisture Stress

2018 ◽  
Vol 102 (4) ◽  
pp. 28-31
Author(s):  
Kirti Bardhan ◽  
Dipika Patel ◽  
Dhiraji Patel
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Root Architecture ◽  
Plant Root ◽  
Moisture Stress ◽  
Rice Roots ◽  
Aerial Parts ◽  
Organ Level ◽  
Plant Root System

The role of K in providing drought tolerance in the aerial parts of plants at the cellular, molecular, tissue, and organ level is well established compared to the plant root system. However, it is known that plants acquire soil water from deeper layers by modifying root architecture. The current study investigated the role of K in changing root architecture to facilitate more water acquisition as a mechanism to mitigate drought stress.

scholarly journals Spermine: Its Emerging Role in Regulating Drought Stress Responses in Plants

Cells ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 261
Author(s):  
Md. Mahadi Hasan ◽  
Milan Skalicky ◽  
Mohammad Shah Jahan ◽  
Md. Nazmul Hossain ◽  
Zunaira Anwar ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Stress Responses ◽  
Abiotic Stresses ◽  
Defense Mechanisms ◽  
Antioxidant Defense ◽  
Severe Drought ◽  
New Information ◽  
Effects Of Drought

In recent years, research on spermine (Spm) has turned up a lot of new information about this essential polyamine, especially as it is able to counteract damage from abiotic stresses. Spm has been shown to protect plants from a variety of environmental insults, but whether it can prevent the adverse effects of drought has not yet been reported. Drought stress increases endogenous Spm in plants and exogenous application of Spm improves the plants’ ability to tolerate drought stress. Spm’s role in enhancing antioxidant defense mechanisms, glyoxalase systems, methylglyoxal (MG) detoxification, and creating tolerance for drought-induced oxidative stress is well documented in plants. However, the influences of enzyme activity and osmoregulation on Spm biosynthesis and metabolism are variable. Spm interacts with other molecules like nitric oxide (NO) and phytohormones such as abscisic acid, salicylic acid, brassinosteroids, and ethylene, to coordinate the reactions necessary for developing drought tolerance. This review focuses on the role of Spm in plants under severe drought stress. We have proposed models to explain how Spm interacts with existing defense mechanisms in plants to improve drought tolerance.

Does plant root architecture respond to potassium nutrition under water stress? A case from rice seedling root responses

2020 ◽  
Author(s):  
Dipika S. Patel ◽  
Bardhan Kirti ◽  
P Patel Dhiraji ◽  
Parekh Vipulkumar ◽  
Jena Suchismita ◽  
...  
Keyword(s):  
Water Stress ◽  
Seedling Growth ◽  
Root Architecture ◽  
Plant Root ◽  
Moisture Stress ◽  
Rice Seedling ◽  
Maximum Width ◽  
High K ◽  
Severe Water Stress ◽  
Low K

ABSTRACTThe root is the sensing organ for potassium (K) and water availability. We evaluated whether K availability influences root architecture and contributes to drought tolerance under moisture stress. Rice seedling growth was severely affected by low K availability under water stress, and the substantial reductions in root projected area, maximum width, and width to depth ratio were observed. High K availability helps maintain root top and bottom angles and reduces root steepness under mild water stress, but over K nutrition does not ensure higher seedling growth. Under severe water stress, the steepness was more regulated by water than K availability.

scholarly journals Exopolysaccharides Producing Bacteria for the Amelioration of Drought Stress in Wheat

2020 ◽  
Vol 12 (21) ◽  
pp. 8876
Author(s):  
Noshin Ilyas ◽  
Komal Mumtaz ◽  
Nosheen Akhtar ◽  
Humaira Yasmin ◽  
R. Z. Sayyed ◽  
...  
Keyword(s):  
Antioxidant Enzymes ◽  
Drought Stress ◽  
Drought Tolerance ◽  
Indole Acetic Acid ◽  
Stress Hormones ◽  
Carotenoid Content ◽  
Bacterial Strains ◽  
Morphological Attributes ◽  
Vigor Index

This research was designed to elucidate the role of exopolysaccharides (EPS) producing bacterial strains for the amelioration of drought stress in wheat. Bacterial strains were isolated from a farmer’s field in the arid region of Pakistan. Out of 24 isolated stains, two bacterial strains, Bacillus subtilis (Accession No. MT742976) and Azospirillum brasilense (Accession No. MT742977) were selected, based on their ability to produce EPS and withstand drought stress. Both bacterial strains produced a good amount of EPS and osmolytes and exhibited drought tolerance individually, however, a combination of these strains produced higher amounts of EPS (sugar 6976 µg/g, 731.5 µg/g protein, and 1.1 mg/g uronic acid) and osmolytes (proline 4.4 µg/mg and sugar 79 µg/mg) and significantly changed the level of stress-induced phytohormones (61%, 49% and 30% decrease in Indole Acetic Acid (IAA), Gibberellic Acid (GA), and Cytokinin (CK)) respectively under stress, but an increase of 27.3% in Abscisic acid (ABA) concentration was observed. When inoculated, the combination of these strains improved seed germination, seedling vigor index, and promptness index by 18.2%, 23.7%, and 61.5% respectively under osmotic stress (20% polyethylene glycol, PEG6000). They also promoted plant growth in a pot experiment with an increase of 42.9%, 29.8%, and 33.7% in shoot length, root length, and leaf area, respectively. Physiological attributes of plants were also improved by bacterial inoculation showing an increase of 39.8%, 61.5%, and 45% in chlorophyll a, chlorophyll b, and carotenoid content respectively, as compared to control. Inoculations of bacterial strains also increased the production of osmolytes such asproline, amino acid, sugar, and protein by 30%, 23%, 68%, and 21.7% respectively. Co-inoculation of these strains enhanced the production of antioxidant enzymes such as superoxide dismutase (SOD) by 35.1%, catalase (CAT) by 77.4%, and peroxidase (POD) by 40.7%. Findings of the present research demonstrated that EPS, osmolyte, stress hormones, and antioxidant enzyme-producing bacterial strains impart drought tolerance in wheat and improve its growth, morphological attributes, physiological parameters, osmolytes production, and increase antioxidant enzymes.

Evidence for Internalization of Escherichia coli into the Aerial Parts of Maize via the Root System†

2007 ◽  
Vol 70 (2) ◽  
pp. 471-475 ◽  
Author(s):  
NIRIT BERNSTEIN ◽  
SHLOMO SELA ◽  
RIKY PINTO ◽  
MARINA IOFFE
Keyword(s):  
Escherichia Coli ◽  
Root System ◽  
Plant Root ◽  
Root Tips ◽  
Monocotyledonous Plant ◽  
E Coli ◽  
Aerial Parts ◽  
Growing Medium ◽  
Maize Plants ◽  
Plant Root System

Escherichia coli introduced into the hydroponic growing medium of maize plants was detected 48 h later in the shoot. Decapitation of root tips or severing of the plant root system at the root-shoot junction enhanced bacterial internalization. The density of the bacteria in shoots of plants with damaged roots or removed root systems was 27.8 and 23.9 times higher than that in plants with intact roots, respectively. The concentration of viable cells in the hydroponic solution decreased over time from 9.3 × 106 CFU/ml at the time of inoculation to 8.5 × 101 CFU/ml 4 days thereafter. The number of E. coli cells associated with the roots also decreased with time, but a significant decline appeared only at 4 days postinoculation. At the time of sampling for E. coli presence in the shoot, 102 CFU/ml was present in the nutrient solution and 8 × 103 CFU/g was associated with the roots. The present study is the first to demonstrate internalization of E. coli via the root in a monocotyledonous plant.

scholarly journals Microbial Diversity of Upland Rice Roots and Their Influence on Rice Growth and Drought Tolerance

2020 ◽  
Vol 8 (9) ◽  
pp. 1329
Author(s):  
Zhiqiang Pang ◽  
Ying Zhao ◽  
Peng Xu ◽  
Diqiu Yu
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Plant Growth ◽  
Upland Rice ◽  
Oryza Sativa L ◽  
Soluble Sugar ◽  
Stress Conditions ◽  
Rice Roots ◽  
Microbial Resources

Among abiotic stresses, drought is one of the most important factors limiting plant growth. To increase their drought tolerance and survival, most plants interact directly with a variety of microbes. Upland rice (Oryza sativa L.) is a rice ecotype that differs from irrigated ecotype rice; it is adapted to both drought-stress and aerobic conditions. However, its root microbial resources have not been explored. We isolated bacteria and fungi from roots of upland rice in Xishuangbanna, China. Four hundred sixty-two endophytic and rhizospheric isolates (337 bacteria and 125 fungi) were distributed. They were distributed among 43 genera on the basis of 16S rRNA and internal transcribed spacer (ITS) gene sequence analysis. Notably, these root microbes differed from irrigated rice root microbes in irrigated environments; for example, members of the Firmicutes phylum were enriched (by 28.54%) in the roots of the upland plants. The plant growth-promoting (PGP) potential of 217 isolates was investigated in vitro. The PGP ability of 17 endophytic and 10 rhizospheric isolates from upland rice roots was evaluated under well-irrigated and drought-stress conditions, and 9 fungal strains increased rice seedling shoot length, shoot and root fresh weight (FW), antioxidant capability, and proline (Pro) and soluble sugar contents. Our work suggests that fungi from upland rice roots can increase plant growth under irrigated and drought-stress conditions and can serve as effective microbial resources for sustainable agricultural production in arid regions.

Evaluation of green gram genotypes for drought tolerance by PEG (polyethylene glycol) induced drought stress at seedling stage

2019 ◽  
Author(s):  
M. Jincya ◽  
V. Babu Rajendra Prasad ◽  
P. Jeyakumara ◽  
A. Senthila ◽  
N. Manivannan
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Moisture Stress ◽  
Germination Percentage ◽  
Seedling Stage ◽  
Green Gram ◽  
Stress Index ◽  
Seedling Mortality ◽  
Seed Vigour ◽  
Selection Of

Drought stress is one of the major constraints for pulse production which negatively affecting its growth and production. Screening and selection of desirable genotypes for drought tolerance is the first and foremost important step in pulse breeding program. In green gram standardization for moisture stress was done under laboratory conditions using various concentration of PEG 6000 and 50% seedling mortality was observed at 0.5 MPa of moisture stress. Using this level of moisture stress 108 green gram genotypes were screened for their drought tolerance at seedling level and the following parameters viz., germination percentage, promptness index, radicle length, root length stress index, germination stress index and seed vigour were recorded. Observations revealed that the following green gram genotypes COGG 1332, VGG 16069, VGG 17003, VGG 17004, VGG 17009, VGG 17019 and VGG 17045 were found highly tolerant to moisture stress at seedling stage.

Evaluation of diverse cowpea [Vigna unguiculata (L.) Walp.] germplasm accessions for drought tolerance

2019 ◽  
Author(s):  
K.D. Nkoana ◽  
Abe Shegro Gerrano ◽  
E.T. Gwata
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Water Content ◽  
Relative Water Content ◽  
Evaluation Method ◽  
Moisture Stress ◽  
Proline Content ◽  
Drought Tolerant ◽  
Relative Water ◽  
Germplasm Accessions

The genetic potential for drought tolerance in cowpea within the small holder sector has not been fully exploited in South Africa. Thus, a drought evaluation experiment was conducted at the ARC-VOP to evaluate 28 cowpea germplasm accessions including two controls viz. IT96D-602 (drought tolerant) and TVU7778 (susceptible to drought) in the drought screening house using plastic box evaluation method in January, 2017. Genotypes raised for three weeks were subjected to 5 weeks of water stress treatment to determine their physiological response through leaf wilting index, relative water content and proline content followed by re-watering to determine genotype (s) with ability to recover from drought stress. Analyses of variance showed highly significant differences in response to moisture stress among the cowpea accessions for the selected physiological traits except for leaf wilting index at week two of drought stress. Stem greenness and recovery appeared to be a reliable indicator of drought tolerant genotypes which was readily observed in Acc1257, Acc1168, Acc2355, IT96D-602 and Acc5352 which also correlated significantly and positively with relative water content and proline content. The genotypes responded differently to drought stress indicating that there is sufficient genetic variability that can be utilized further in breeding for drought stress within the cowpea species.

Assessment of Drought Tolerance Indices in Bread Wheat Genotypes Under Different Sowing Dates

2012 ◽  
Vol 45 (3) ◽  
pp. 25-39 ◽  
Author(s):  
S. Mohammadi ◽  
M. Janmohammadi ◽  
A. Javanmard ◽  
N. Sabaghnia ◽  
M. Rezaie ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Grain Yield ◽  
High Performance ◽  
Wheat Yield ◽  
Moisture Stress ◽  
Drought Indices ◽  
Terminal Drought ◽  
Sowing Dates ◽  
Moisture Conditions

Abstract The capability of a genotype to achieve acceptable yield over a broad range of sub-optimum and suitable conditions is extremely imperative. Late planting and end-season drought stress are two main factors limiting wheat yield in northwest of Iran. In a 2-year field experiment at Miandoab, Iran, the ability of several selection indices to identify drought resistant genotypes under different sowing dates and moisture conditions were evaluated. Six genotypes of differing response to water scarcity were planted at 20-d intervals on three dates from 11 October to 20 November. Drought resistance indices were utilized on the basis of grain yield under end-season drought (Ys) and normal (YN) conditions. Evaluation of MP, HARM, GM, STI, TOL, SSI, RDI, YSI and Yr indicated that late sowing (20 Nov) significantly decreased drought tolerance in all investigated genotypes. However, yield comparisons under normal and terminal drought stress conditions revealed that promising lines (C-81-4, C-81- 10, C-81-14 and C-82-12) had better performance than local checks (Zarrin and Alvand). Furthermore under both moisture conditions C-81-10 genotype had the greatest grain yield. Based on drought indices like as MP, GMP, STI and HARM C-81-10 genotype introduced as the most tolerant genotype to end-season drought stress. Grain yield showed a positive and significant correlation with HARM, GMP, MP, STI and YI indices were more efficient for recognizing high performance genotypes under different sowing dates and diverse moisture stress.

scholarly journals Physiological, Biochemical and Transcriptomic Analysis of the Aerial Parts (Leaf-Blade and Petiole) of Asarum sieboldii Responding to Drought Stress

2021 ◽  
Vol 22 (24) ◽  
pp. 13402
Author(s):  
Fawang Liu ◽  
Tahir Ali ◽  
Zhong Liu
Keyword(s):  
Gene Expression ◽  
Drought Stress ◽  
Essential Oil ◽  
Drought Tolerance ◽  
Leaf Blade ◽  
Vital Role ◽  
Biomass Energy ◽  
Cdna Libraries ◽  
Regulatory Pathways ◽  
Aerial Parts

Asarum sieboldii Miq. is a leading economic crop and a traditional medicinal herb in China. Leaf-blade and petiole are the only aerial tissues of A. sieboldii during the vegetative growth, playing a vital role in the accumulation and transportation of biomass energy. They also act as critical indicators of drought in agricultural management, especially for crops having underground stems. During drought, variations in the morphology and gene expression of the leaves and petioles are used to control agricultural irrigation and production. Besides, such stress can also alter the differential gene expression in these tissues. However, little is known about the drought-tolerant character of the aerial parts of A. sieboldii. In this study, we examined the physiological, biochemical and transcriptomic responses to the drought stress in the leaf blades and petioles of A. sieboldii. The molecular mechanism, involving in drought stress response, was elucidated by constructing the cDNA libraries and performing transcriptomic sequencing. Under drought stress, a total of 2,912 and 2,887 unigenes were differentially expressed in the leaf blade and petiole, respectively. The detection of many transcription factors and functional genes demonstrated that multiple regulatory pathways were involved in drought tolerance. In response to drought, the leaf blade and petiole displayed a general physiological character, a higher SOD and POD activity, a higher MDA content and lower chlorophyll content. Three unigenes encoding POD were up-regulated, which can improve POD activity. Essential oil in petiole was extracted. The relative contents of methyleugenol and safrole in essential oil were increased from 0.01% to 0.05%, and 3.89% to 16.97%, respectively, while myristicin slightly reduced from 24.87% to 21.52%. Additionally, an IGS unigene, involved in eugenol biobiosynthesis, was found up-regulated under drought stress, which was predicated to be responsible for the accumulation of methyleugenol and safrole. Simple sequence repeats (SSRs) were characterized in of A. sieboldii, and a total of 5,466 SSRs were identified. Among them, mono-nucleotides were the most abundant repeat units, accounting for 44.09% followed by tri-, tetra-, penta and hexa-nucleotide repeats. Overall, the present work provides a valuable resource for the population genetics studies of A. sieboldii. Besides, it provides much genomic information for the functional dissection of the drought-resistance in A. sieboldii., which will be useful to understand the bio-regulatory mechanisms linked with drought-tolerance to enhance its yield.

scholarly journals Amplification of early drought responses caused by volatile cues emitted from neighboring plants

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Jieyang Jin ◽  
Mingyue Zhao ◽  
Ting Gao ◽  
Tingting Jing ◽  
Na Zhang ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Plant Density ◽  
Stomatal Closure ◽  
Induced Volatiles ◽  
Positive Regulators ◽  
Tea Plants ◽  
Aba Content ◽  
Volatile Cues

AbstractPlants have developed sophisticated mechanisms to survive in dynamic environments. Plants can communicate via volatile organic compounds (VOCs) to warn neighboring plants of threats. In most cases, VOCs act as positive regulators of plant defense. However, the communication and role of volatiles in response to drought stress are poorly understood. Here, we showed that tea plants release numerous VOCs. Among them, methyl salicylate (MeSA), benzyl alcohol, and phenethyl alcohol markedly increased under drought stress. Interestingly, further experiments revealed that drought-induced MeSA lowered the abscisic acid (ABA) content in neighboring plants by reducing 9-cis-epoxycarotenoid dioxygenase (NCED) gene expression, resulting in inhibition of stomatal closure and ultimately decreasing early drought tolerance in neighboring plants. Exogenous application of ABA reduced the wilting of tea plants caused by MeSA exposure. Exposure of Nicotiana benthamiana to MeSA also led to severe wilting, indicating that the ability of drought-induced MeSA to reduce early drought tolerance in neighboring plants may be conserved in other plant species. Taken together, these results provide evidence that drought-induced volatiles can reduce early drought tolerance in neighboring plants and lay a novel theoretical foundation for optimizing plant density and spacing.

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