scholarly journals Real-Time Water Movement in a Plant

2021 ◽  
pp. 39-72
Author(s):  
Tomoko M. Nakanishi
Keyword(s):  
Drought Tolerance ◽  
Water Absorption ◽  
Water Movement ◽  
Sensitive Strain ◽  
Important Lesson ◽  
Tolerant Strain ◽  
Drought Tolerant ◽  
Tolerant Plants ◽  
Tremendous Amount ◽  
Trace Water

AbstractThe next approach to research on water was to measure the small amount of water actually moving within a plant. The best method is to utilize radioisotope (RI)-labeled water and measure the radiation from outside of the plant. However, it is rather difficult to label water, since there are only limited kinds of RI for tracing water.When utilizing 18F to trace water movement, another fundamental question to consider was the features that characterize drought-tolerant and drought-sensitive plants. It is natural to suppose that drought-tolerant plants have strong water absorption; therefore, by analyzing the water absorption mechanism of tolerant plants and by introducing this function to sensitive plants, it might be possible to make the sensitive plants more tolerant.However, when water uptake was studied in naturally developed drought-tolerant and drought-sensitive cowpea, selected from 2000 cowpea plants grown in the field of Africa, the result was unexpected. Under normal conditions, the amount of water absorbed by the drought-tolerant strain was much lower than that absorbed by the sensitive strain, as if showing the low capability of water absorption. When a drought condition was introduced, the tolerant strain began to absorb much more water than usual, whereas the sensitive strain could not absorb as much water as before. This result provided us with an important lesson. Analyzing the mechanism of drought tolerance only by comparing the water absorption of tolerant and sensitive plants might not readily reveal the reason for drought tolerance. The features of the naturally produced plants showed us different mechanisms that might not match our expectations developed in the laboratory.Next, we performed water measurements using 15O-labeled water, which has an extremely short half-life of 2 minutes. Here, we found another astonishing result, which was “water circulation” in the plant internode. A tremendous amount of water was always leaking from xylem cells, which had been regarded as a mere pipe to transfer water from the root to the aboveground parts. In another subsequent study, it was shown that the water flowing out from the xylem was pushing out the water already present in the stem and then returning to the xylem again to move upward. The water velocity in the internode was kept constant, and through simulation, it took less than 20 minutes to exchange the water already present in the stem with newly absorbed water.

Evaluation of drought tolerance and screening for drought-tolerant indicators in sweetpotato cultivars

2019 ◽  
Vol 45 (3) ◽  
pp. 419 ◽  
Author(s):  
Hai-Yan ZHANG ◽  
Bei-Tao XIE ◽  
Bao-Qing WANG ◽  
Shun-Xu DONG ◽  
Wen-Xue DUAN ◽  
...  
Keyword(s):  
Drought Tolerance ◽  
Drought Tolerant

scholarly journals Improving Drought Tolerance in Mungbean (Vigna radiata L. Wilczek): Morpho-Physiological, Biochemical and Molecular Perspectives

Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1534
Author(s):  
Chandra Mohan Singh ◽  
Poornima Singh ◽  
Chandrakant Tiwari ◽  
Shalini Purwar ◽  
Mukul Kumar ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Crop Production ◽  
Mitigation Strategies ◽  
Theoretical Research ◽  
Whole Genome Sequence ◽  
Complex Nature ◽  
Drought Tolerant ◽  
Breeding Programmes ◽  
The Impact

Drought stress is considered a severe threat to crop production. It adversely affects the morpho-physiological, biochemical and molecular functions of the plants, especially in short duration crops like mungbean. In the past few decades, significant progress has been made towards enhancing climate resilience in legumes through classical and next-generation breeding coupled with omics approaches. Various defence mechanisms have been reported as key players in crop adaptation to drought stress. Many researchers have identified potential donors, QTLs/genes and candidate genes associated to drought tolerance-related traits. However, cloning and exploitation of these loci/gene(s) in breeding programmes are still limited. To bridge the gap between theoretical research and practical breeding, we need to reveal the omics-assisted genetic variations associated with drought tolerance in mungbean to tackle this stress. Furthermore, the use of wild relatives in breeding programmes for drought tolerance is also limited and needs to be focused. Even after six years of decoding the whole genome sequence of mungbean, the genome-wide characterization and expression of various gene families and transcriptional factors are still lacking. Due to the complex nature of drought tolerance, it also requires integrating high throughput multi-omics approaches to increase breeding efficiency and genomic selection for rapid genetic gains to develop drought-tolerant mungbean cultivars. This review highlights the impact of drought stress on mungbean and mitigation strategies for breeding high-yielding drought-tolerant mungbean varieties through classical and modern omics technologies.

scholarly journals Drought Tolerant near Isogenic Lines (NILs) of Pusa 44 Developed through Marker Assisted Introgression of qDTY2.1 and qDTY3.1 Enhances Yield under Reproductive Stage Drought Stress

Agriculture ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 64
Author(s):  
Priyanka Dwivedi ◽  
Naleeni Ramawat ◽  
Gaurav Dhawan ◽  
Subbaiyan Gopala Krishnan ◽  
Kunnummal Kurungara Vinod ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Grain Quality ◽  
Reproductive Stage ◽  
Recurrent Parent ◽  
Near Isogenic Lines ◽  
Improvement Project ◽  
Isogenic Lines ◽  
Drought Tolerant ◽  
Rice Improvement

Reproductive stage drought stress (RSDS) is detrimental for rice, which affects its productivity as well as grain quality. In the present study, we introgressed two major quantitative trait loci (QTLs), namely, qDTY2.1 and qDTY3.1, governing RSDS tolerance in a popular high yielding non-aromatic rice cultivar, Pusa 44, through marker-assisted backcross breeding (MABB). Pusa 44 is highly sensitive to RSDS, which restricts its cultivation across drought-prone environments. Foreground selection was carried out using markers, RM520 for qDTY3.1 and RM 521 for qDTY2.1. Background selection was achieved with 97 polymorphic SSR markers in tandem with phenotypic selection to achieve faster recurrent parent genome (RPG) recovery. Three successive backcrosses followed by three selfings aided RPG recoveries of 98.6% to 99.4% among 31 near isogenic lines (NILs). Fourteen NILs were found to be significantly superior in yield and grain quality under RSDS with higher drought tolerance efficiency (DTE) than Pusa 44. Among these, the evaluation of two promising NILs in the multilocational trial during Kharif 2019 showed that they were significantly superior to Pusa 44 under reproductive stage drought stress, while performing on par with Pusa 44 under normal irrigated conditions. These di-QTL pyramided drought-tolerant NILs are in the final stages of testing the All India Coordinated Rice Improvement Project varietal trials for cultivar release. Alternately, the elite drought-tolerant Pusa 44 NILs will serve as an invaluable source of drought tolerance in rice improvement.

scholarly journals Genetic Diversity of Selected Rice Genotypes under Water Stress Conditions

Plants ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 27
Author(s):  
Mahmoud M. Gaballah ◽  
Azza M. Metwally ◽  
Milan Skalicky ◽  
Mohamed M. Hassan ◽  
Marian Brestic ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Water Stress ◽  
Drought Stress ◽  
Drought Tolerance ◽  
Ssr Markers ◽  
Similarity Index ◽  
Stress Conditions ◽  
Yield Potential ◽  
Drought Tolerant ◽  
Rice Genotypes

Drought is the most challenging abiotic stress for rice production in the world. Thus, developing new rice genotype tolerance to water scarcity is one of the best strategies to achieve and maximize high yield potential with water savings. The study aims to characterize 16 rice genotypes for grain and agronomic parameters under normal and drought stress conditions, and genetic differentiation, by determining specific DNA markers related to drought tolerance using Simple Sequence Repeats (SSR) markers and grouping cultivars, establishing their genetic relationship for different traits. The experiment was conducted under irrigated (normal) and water stress conditions. Mean squares due to genotype × environment interactions were highly significant for major traits. For the number of panicles/plants, the genotypes Giza179, IET1444, Hybrid1, and Hybrid2 showed the maximum mean values. The required sterility percentage values were produced by genotypes IET1444, Giza178, Hybrid2, and Giza179, while, Sakha101, Giza179, Hybrid1, and Hybrid2 achieved the highest values of grain yield/plant. The genotypes Giza178, Giza179, Hybrid1, and Hybrid2, produced maximum values for water use efficiency. The effective number of alleles per locus ranged from 1.20 alleles to 3.0 alleles with an average of 1.28 alleles, and the He values for all SSR markers used varied from 0.94 to 1.00 with an average of 0.98. The polymorphic information content (PIC) values for the SSR were varied from 0.83 to 0.99, with an average of 0.95 along with a highly significant correlation between PIC values and the number of amplified alleles detected per locus. The highest similarity coefficient between Giza181 and Giza182 (Indica type) was observed and are susceptible to drought stress. High similarity percentage between the genotypes (japonica type; Sakha104 with Sakha102 and Sakha106 (0.45), Sakha101 with Sakha102 and Sakha106 (0.40), Sakha105 with Hybrid1 (0.40), Hybrid1 with Giza178 (0.40) and GZ1368-S-5-4 with Giza181 (0.40)) was also observed, which are also susceptible to drought stress. All genotypes are grouped into two major clusters in the dendrogram at 66% similarity based on Jaccard’s similarity index. The first cluster (A) was divided into two minor groups A1 and A2, in which A1 had two groups A1-1 and A1-2, containing drought-tolerant genotypes like IET1444, GZ1386-S-5-4 and Hybrid1. On the other hand, the A1-2 cluster divided into A1-2-1 containing Hybrid2 genotype and A1-2-2 containing Giza179 and Giza178 at coefficient 0.91, showing moderate tolerance to drought stress. The genotypes GZ1368-S-5-4, IET1444, Giza 178, and Giza179, could be included as appropriate materials for developing a drought-tolerant variety breeding program. Genetic diversity to grow new rice cultivars that combine drought tolerance with high grain yields is essential to maintaining food security.

Evidence for direct water absorption by the shoot of the desiccation-tolerant plant Vellozia flavicans in the savannas of central Brazil

2005 ◽  
Vol 21 (5) ◽  
pp. 585-588 ◽  
Author(s):  
Rafael S. Oliveira ◽  
Todd E. Dawson ◽  
Stephen S. O. Burgess
Keyword(s):  
Water Absorption ◽  
Moisture Absorption ◽  
Terrestrial Plants ◽  
Desert Ecosystems ◽  
Common View ◽  
Central Brazil ◽  
Tolerant Plants ◽  
Aerial Roots ◽  
Alternative Water ◽  
Specialized Structure

Our common view on water uptake by terrestrial plants is that it occurs via absorption by roots from the soil substrate. However, it has long been known that plants exhibit alternative water-absorption strategies, particularly in drought-prone environments. Examples include many tropical epiphytic orchids which use a specialized structure called velamen radicum around their aerial roots for moisture absorption directly from the air (Capesius & Barthlott 1975), specialized trichomes in bromeliads (Andrade 2003, Benzing 1990), uptake by hydathodes into leaves of species inhabiting dry desert ecosystems of Namibia (Martin & von Willert 2000) and foliar absorption by coastal California redwoods during the summer fog season (Burgess & Dawson 2004). One of the most intriguing and yet, least-studied examples of adaptations to severe water limitation is found with desiccation-tolerant plants (also called resurrection plants). During drought periods, the water content of these plants can equilibrate with the low relative humidity of the air to the point that the plants appear dead. However, when water is supplied, these plants fully rehydrate (Alpert 2000, Bewley & Krochko 1982) and become physiologically active. Desiccation-tolerant vascular plants are rare in most ecosystems but diverse in tropical inselbergs (granitic outcrops; Porembski & Barthlott 2000). Relatively little is known about inselberg species particularly from an ecophysiological perspective (see Lüttge 1997 and Klüge & Brulfert 2000 for reviews).

Reaction of Drought-Tolerant Soybean Genotypes to Macrophomina phaseolina

2008 ◽  
Vol 9 (1) ◽  
pp. 16 ◽  
Author(s):  
J. A. Wrather ◽  
J. G. Shannon ◽  
T. E. Carter ◽  
J. P. Bond ◽  
J. C. Rupe ◽  
...  
Keyword(s):  
Drought Tolerance ◽  
Common Bean ◽  
Root Colonization ◽  
Macrophomina Phaseolina ◽  
Common Disease ◽  
Charcoal Rot ◽  
Stages Of Growth ◽  
Drought Tolerant ◽  
Soybean Genotypes ◽  
Moderately Resistant

Charcoal rot caused by Macrophomina phaseolina is a common disease of many crops including common bean and soybean. Incidence and severity of charcoal rot are enhanced when plants are drought stressed. Resistance to this pathogen in some common bean genotypes was associated with drought tolerance. Resistance to M. phaseolina among soybean genotypes has not been identified, although a few have been rated moderately resistant based on less root tissue colonization by this pathogen compared to other genotypes. A few soybean genotypes have been rated as slow-wilt or drought-tolerant. The reaction of drought-tolerant soybean to M. phaseolina compared to intolerant or drought-sensitive genotypes has not been determined. Our objective was to determine if there were differences in root colonization by M. phaseolina between drought-tolerant and drought-sensitive soybean genotypes. Drought tolerance of the soybean genotypes and root colonization by M. phaseolina at the R6 and R8 stages of growth were not related in this study. Some drought-tolerant soybean genotypes may resist root colonization by M. phaseolina, but our results suggest that this is not true for all drought-tolerant genotypes. Accepted for publication 21 March 2008. Published 18 June 2008.

scholarly journals C-Repeat Binding Factor and Dehydrin Genes are Induced Co-Ordinately in Drought Tolerance Response of Wheat Cultivars

2017 ◽  
Vol 9 (2) ◽  
pp. 18 ◽  
Author(s):  
Csilla Deák ◽  
Katalin Jäger ◽  
Veronika Anna Nagy ◽  
Réka Oszlányi ◽  
Beáta Barnabás ◽  
...  
Keyword(s):  
Drought Tolerance ◽  
Mrna Level ◽  
Drought Treatment ◽  
Drought Tolerant ◽  
Aba Sensitivity ◽  
Defence Genes ◽  
Binding Factor ◽  
Tolerance Response ◽  
Pcr Method

Four bread wheat genotypes with contrasting drought stress tolerance were studied. Expression levels of dehydrin (Wdhn13) and C-repeat binding factor (Cbf14, Cbf15) genes were investigated in leaves of two drought tolerant (Plainsman V, Mv Emese) and two sensitive (GK Élet, Cappelle Desprez) cultivars by semi-quantitative RT-PCR during drought treatment at anthesis. Coordinate induction of Cbf14, Cbf15 and Wdhn13 genes occurred at a late stage of stress treatment in all cultivars except the most sensitive Cappelle Desprez, where no induction was evident. The most pronounced late induction of genes was observed in the tolerant Mv Emese genotype. Cbf14, Cbf15 and Wdhn13 showed largely parallel changes of expression in stressed adult plants. The mRNA level of the same set of genes was measured in leaves of non-stressed seedlings with qRT-PCR method. Expression level of Wdhn13 was high and low in seedlings of tolerant and sensitive cultivars, respectively. Cbf15 specific transcript was barely detectable in leaves of non-stressed seedlings. In order to shed light on any potential difference in hormone responsiveness, seedlings were subjected to ABA treatment in vitro. At low hormone concentrations (10 and 20 µM ABA) consistently weaker ABA induced root growth retardation of GK Élet was found in comparison with the other three cultivars. Results highlight pronounced and late induction of a set of defence genes and low ABA sensitivity as features appearing in drought tolerant and sensitive responses, respectively. Data is discussed in the light of multifactorial determination of the complex phenotype of drought tolerance in wheat.

scholarly journals Contribution of Ascorbate and Glutathione in Endobacteria Bacillus subtilis-Mediated Drought Tolerance in Two Triticum aestivum L. Genotypes Contrasting in Drought Sensitivity

Plants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2557
Author(s):  
Dilara Maslennikova ◽  
Oksana Lastochkina
Keyword(s):  
Triticum Aestivum ◽  
Bacillus Subtilis ◽  
Drought Tolerance ◽  
Triticum Aestivum L ◽  
Subtilis Strain ◽  
Wheat Cultivars ◽  
Stress Markers ◽  
Drought Tolerant ◽  
Adaptation To Drought ◽  
Significant Activation

We evaluated the effect of endobacteria Bacillus subtilis (strain 10–4) as a co-inoculant for promoting plant growth and redox metabolism in two contrasting genotypes of Triticum aestivum L. (wheat): Ekada70 (drought tolerant (DT)) and Salavat Yulaev (drought susceptible (DS)) in early stages of adaptation to drought (12% PEG–6000). Results revealed that drought reduced growth and dramatically augmented oxidative stress markers, i.e., hydrogen peroxide (H2O2) and lipid peroxidation (MDA). Furthermore, the depletion of ascorbate (AsA) and glutathione (GSH), accompanied by a significant activation of ascorbate peroxidase (APX) and glutathione reductase (GR), in both stressed wheat cultivars (which was more pronounced in DS genotype) was found. B. subtilis had a protective effect on growth and antioxidant status, wherein the stabilization of AsA and GSH levels was revealed. This was accompanied by a decrease of drought-caused APX and GR activation in DS plants, while in DT plants additional antioxidant accumulation and GR activation were observed. H2O2 and MDA were considerably reduced in both drought-stressed wheat genotypes because of the application of B. subtilis. Thus, the findings suggest the key roles in B. subtilis-mediated drought tolerance in DS cv. Salavat Yulaev and DT cv. Ekada70 played are AsA and GSH, respectively; which, in both cases, resulted in reduced cell oxidative damage and improved growth in seedlings under drought.

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