<div>Abiotic stresses adversely affect plant growth and ultimately crop productivity. Of these, water-logging is the most widespread and most commonly experienced stress factor. While water is essential for all plant growth and development processes, waterlogging is an obstacle to sustainable agriculture. Recent FAO reports indicate that universal crop production must be enhanced by 70% by 2050 in order to meet the growing demand for food by an estimated 2.3 billion people. As demand for food increases, there is an urgent need to identify environment-friendly strategies capable of being accepted and adopted widely to enhance crop yields and mitigate the effects of climate change. Nanotechnology as a science of manipulating materials at the nano-scale has significant potential to enhance agricultural productivity by nonconventional means. This technology has been gaining momentum lately as a possible solution to reduce the adverse effects associated with various stresses, particularly with waterlogging, to enhance future food security. This paper discusses the potential applications of nanoparticles to achieve sustainable crop productivity, together with their impact on the mechanism of tolerance to waterlogging stress.</div>


<p>Application of Nanobiotechnology in Enabling Plants to Overcome Water-logging Stress: A Review</p>


<p>In rice, several cultivated and upland varieties need to be assessed and analyzed for drought tolerance traits which could be used in screening and breeding programs for drought tolerance. Hence, the objectives of this study were to investigate the effects of water deficits in two rice cultivars and thereby analyze the role of several physiological traits useful in rice breeding programs for drought tolerance. The rice varieties Tellahamsa (TH) and N22 were screened for tolerance to drought. A comparative study was done subjecting them to PEG mediated water stress. Accumulation of solutes, i.e., proline, total free aminoacids and sugars; biomass production, Relative Water Content (RWC) and the levels of &nbsp;antioxidant enzymes, viz., Catalase (CAT), Ascorbate Peroxidase (APX), Glutathione Reductase(GR), and Superoxide Dismutase(SOD) were analyzed in response to water stress. Maximum proline accumulation was seen within 24hrs of stress, after 10 days TH decreased its proline to one-third, whereas in N22 doubled. Although amino acids doubled within 24hrs, gradually they depleted in N22. This may be due to conversion of aminoacids into proline which could be the most compatible solute. Sugars increased within 24hrs, but were depleted in 10days in both. In TH, the shoot and root biomass decreased, whereas in N22 there was a significant increase in root biomass. Shoot and root RWC of N22 was higher than TH under stress. GR increased in both TH and N22, APX and SOD increased only in N22. Proline accumulation, increase of root biomass and &nbsp;antioxidant enzymes such as APX or SOD during water stress are contributing to drought tolerance and could be used in screening for drought tolerance.</p>


<p>Effect of PEG mediated water stress on solute accumulation, relative water content, biomass and antioxidant enzymes in rice</p>


<div><strong>Background:</strong> Chickpea is a pivotal grain legume crop and is grown in rain-fed conditions where its production has been challenged by drought.&nbsp;<br />
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<strong>Methods: </strong>To understand precisely the root-based responses to well-watered (WW) and water-stressed (WS) treatments, 14 chickpea (<em>Cicer arietinum</em> L.) genotypes differing in drought tolerance and biomass were studied in 100-cm cylinders under glasshouse conditions.&nbsp;<br />
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<strong>Result:</strong> The genotypes exhibited significant variations in rooting depths ranging from 84.5 to 100.3 cm and 78.7 to 121 cm in WW and WS treatments, respectively and root biomasses varied from 0.23 to 1.01 g and 0.38 to 0.91 g. The average root biomass of drought-tolerant genotypes was 61.3% in WS treatment and 64.4% in WW treatment higher than that of drought-sensitive genotypes. Moreover, genotype with high biomass revealed greater root biomass and deeper rooting than the genotype with low biomass in both treatments. The root biomass in the deeper soil profile differed between drought-tolerant and drought-sensitive genotypes and was generally greater in WS compared to WW treatment. Overall, screening the variability in root features of chickpea genotypes with varying levels of drought tolerance and biomass contributes to new insights for understanding drought adaptation mechanisms and the improvement of new cultivars with superior root traits in breeding programs.&nbsp;</div>


<div>Root-based Responses of Well-watered and Water-stressed Chickpea (<em>Cicer arietinum</em> L.) Genotypes Varying for Drought Tolerance and Biomass&nbsp;</div>


<div><strong>Background: </strong>Lentil mainly grows on residual soil moisture under rainfed conditions leading to abrupt soil moisture depletion causing mid or terminal drought stress to plants. Application of supplemental irrigation and adopting high yielding cultivars could alleviate drought stress and secure higher yield. Our present study aimed to study the growth of some promising varieties of lentil under four moisture regimes.&nbsp;<br />
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<strong>Methods: </strong>To study the physiological responses of some promising lentil varieties under water stress, a pot experiment was performed at Bidhan Chandra Krishi Viswavidyalaya, Nadia, West Bengal during 2018-2019. Four lentil varieties <em>i.e.</em> Asha, PL 6, Subrata and Ranjan were grown under four moisture stress treatments through supplying water maintaining irrigation water (IW): cumulative pan evaporation (CPE) at its 100, 75, 50 and 25%.<br />
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<strong>Result: </strong>Without stress condition Asha maintained the highest RLWC of 82.6 &nbsp;and 66.1% during flowering and pod formation stages, respectively; while Subrata got the maximum chlorophyll content (2.82 g l<sup>-1</sup>) during flowering stage. Under no stress root length density, root surface area and root volume were experienced the maximum values in all varieties, while, average root diameter was the highest under severe stress treatment for Ranjan. Our study concluded that Asha had potential to withstand water stress but Subrata was proved to be the best variety under no stress condition.</div>


<div>Effect of Water Stress on Growth and Root Characteristics of Lentil</div>


<p><strong>Background:</strong> Water- logging stress is one of the important abiotic stress in pigeon pea crop especially in low lying areas in pigeon pea growing states. Being a rainy season crop, pigeon pea is invariably exposed to intermittent water-logging conditions for different durations from germination to early vegetative growth stages, which damage the crop partially and sometime eliminate the entire crop depending on intensity and duration of water stagnation. The present experiment was conducted to study the morphological characters and yield performance of water logging tolerant and susceptible pigeon pea genotypes so that large number of pigeon pea genotypes for water logging tolerance based on morphological and Physiological parameters standardized might be screened.<br />
&nbsp;<br />
<strong>Methods:</strong> As per approved technical programme, the experiment was conducted with 30 pigeon pea genotypes including checks, these were IPAC-79, ICPL-7035, ICPL-20241, ICPL-87051, ICPL-87091, ICP-2376, ICP-5028, ICPL-149, MA-3, MA-6, NDA-1, IPA-15F, Bahar, IPA-203, IPAC-211, IPAC-202, RCM/DD-17, WB-2019/25, WB-2019/26, WB-2019/27, IPAC-212, IPAWL-22-1, IPAWL-22.2, IPAWL-22-3, IPAWL-22-4, IPAWL- 22-5, IPAWL-22-6, IPAWL-22-7, IPAWL -22-8, IPAWL -22-9. Water logging stress was imposed for 24 h-48h-72h having minimum depth of water 12 inches at 30 DAS with 03 replications and a set of all these genotypes were also sown under normal control condition. Morphological Scoring (0-3) at the end of water logging stress was done. and at harvesting yield attributes and yields were recorded.<br />
&nbsp;</p>

<p><strong>Result: </strong>Morphological Scoring (0-3) at the end of water logging stress showed highest score (0) in genotypes including IPAC-79 (Check for Tolerant) followed by ICPL-87091, ICP-2376, ICPL-20241, IPAC-212, IPAWL-22-7 and IPAWL-22-8 and may be considered as water logging tolerant. Pigeon pea genotypes like ICP-5028, MA-6 and IPAC-202 showed the score of (01) and may be considered as moderately tolerant to water logging stress. Pigeon pea genotypes namely MA-3, NDA-1, IPA-15F, Bahar, IPAC-211, IPA-203, IPAWL-22-6 and IPAWL-22-9 showed moderate score (02) and may be considered as moderately susceptible. The lowest score (03) was recorded in ICPL-87051, ICP-149, RCM/DD-17, WB-2019/25, WB-2019/26, WB-2019/27, IPAWL-22-1, IPAWL-22-2, IPAWL-22-3, IPAWL-22-4 and IPAWL-22-5 and these were at par with ICPL-7035 (Check for susceptibility) and considered susceptible to water logging stress. Development of adventitious roots was observed under water logged condition only and it was recorded highest in genotypes which are water logging tolerant group. In susceptible genotypes no/negligible adventitious roots were found. In yield attributes and yield the reduction % due to water logging stress over normal control was minimum in tolerant/moderately tolerant genotypes whereas, it was found maximum in Susceptible/moderately susceptible group of genotypes.</p>


<p>Physiological Characterization of Pigeon Pea Genotypes [<em>Cajanus cajan</em> (L) Mill sp.]&nbsp; for Water Logging Tolerance</p>


<div>Water deficit stress is one of the chief abiotic stresses adversely affecting plant endurance leading serious effects on plant metabolism. Depending upon strength and duration of water deficit conditions, plants adjust a series of physiological, cellular and molecular mechanisms aiming a correct stress response. Some of the responses of plants to water stress include decreased growth and development and hence decrease in fresh biomass, decreased content of chlorophyll and hence the decreased rate of photosynthesis, decrease in leaf relative water content (RWC) and increased accumulation of osmolytes like proline, sucrose, soluble carbohydrates,<em> etc</em>. Several enzymes involved in carbohydrate metabolism seem to play a role in the multi-layered response of plants to water deficiency. Glycolysis is a central metabolic pathway that provide elasticity when production of energy for existence is confronted and is modulated to establish a novel homeostasis under stress conditions in plants. Evidence for the participation of glycolytic genes, proteins and enzymes in response to stress is established by the fact that their expression is deeply affected by exposure of plant tissues to environmental stresses such as drought. Keeping in mind the importance of glycolytic pathway during stress conditions in plants, the impact of the drought stress on plant glycolysis is the subject of current review. In addition, plant physiology and carbohydrate metabolism under drought stress are also discussed.</div>


<p>Plant Metabolism during Water Deficit Stress: A Review</p>


<div><strong>Background: </strong>Green gram is one of the important pulse crops of chief protein source, with ability to fix nitrogen. Erratic rainfall, while it&rsquo;s grown as rainfed crop, leads to the yield loss due to water stress. Plant root system architecture is plastic and is important sink of photosynthates. In general, the ability of plants to change its root distribution for exploiting water deeper in soil profiles can be an important mechanism to avoid soil water stress. Identification of genotypes based on root traits under water stress conditions will aid in development of drought tolerant varieties for yield exploitation.&nbsp;<br />
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<strong>Methods:</strong> The experiment was conducted during <em>Rabi</em>, 2018-19 with five green gram varieties as main treatment and irrigation intervals as sub treatments in three replications in factorial RBD in root structures. Observations were recorded on root parameters at flowering stage. The root structures were dismantled during flowering stage and all the plants removed from the soil without damaging the roots by using water with jet pump. Five representative samples were collected under different stress level. Root studies were performed with Delta T automatic root scanner. The SPAD chlorophyll meter was used to measure canopy leaves and average of the three readings was taken as SCMR value.&nbsp;<br />
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<strong>Result: </strong>The present study results on root studies revealed that genotype, MGG-295 recorded highest mean plant height under three stress conditions and same genotype also produced longer root length under mild water stress conditions, higher SCMR values under non-stress and mild stress. Genotype, MGG-347 recorded highest root diameter under non- stress and mild stress. MGG-385 produced highest root length under control and severe stresses, highest SCMR values under severe stress, root dry weight under mild and severe water stresses and total plant dry weight under control and mild stress. MGG-360 recorded higher shoot fresh weight under severe stress and same genotype also recorded significant superior values for total root area under mild and severe water stress and root tip count under non-stress, mild stress and severe stress. MGG-351 recorded shoot fresh weight under non stress and mild stress situations and the same genotype recorded highest values for root diameter and total plant dry weight under severe stress. The identified genotypes can be used as water stress resistant genotypes in future drought proof breeding programmes.</div>


<p>Studies on the Effect of Water Stress on Root Traits in Green Gram Cultivars</p>


<div><strong>Background: </strong>Drought is one of the most important abiotic factors that limit the growth and development of plants all over the world. In Ethiopia, wheat is the second most important crop and occupies third in total production in the African countries. Low productivity as compared to the national production scale is due to water stress. The present work aimed to study the effect of water stress on the growth and yield performance of wheat.<br />
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<strong>Methods: </strong>The experiment was conducted in an exceeding greenhouse at East Gojjam Zone, Debre Markos University in 2017-2018 to assess the effects of wheat to water stress applied at different growth stages. The experiment comprised of two water stress treatments, maintained by withholding water at tillering, anthesis and at each stage. Different growth and yield performance data were collected and analyzed by SAS software.<br />
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<strong>Result: </strong>Water stress caused a reduction in leaf relative water contents, water potential, osmotic potential, turgor potential, growth and yield components of the wheat. The results indicated that successive stress at growth stages caused a severe reduction in vegetative growth parameters of wheat. Therefore, the results indicated that the high value of relative water content was related to exaggerated yield and its components of crops. The water-stressed treatment has reduced the growth and yield performance of wheat than unstressed treatments. This was due to a reduction in the osmotic activities of plants.</div>


<div>Growth and Yield Performance of Wheat (<em>Triticum aestivum </em>L.) to under Water Stress Conditions</div>


<div style="text-align:justify">
<div style="text-align: left;"><strong>Background:</strong> Water stress is one of the most crucial limiting factors in maize production on Ultisols. One solution that could be adopted to solve this problem is applying organic soil amendment.</div>

<div style="text-align: left;"><br />
<strong>Methods:</strong> This study evaluated three varieties of corn: NK-Jumbo, Srikandi Kuning and Lamuru. The water stress treatment consists of 75% field capacity (without water stress) and 37.5% field capacity (water stress treatment). The organic amendment consists of without soil amendment, rice-straw 10 tons ha<sup>-1</sup>, biochar 10 tons ha<sup>-1</sup> and rice straw 5 tons ha<sup>-1</sup> + biochar 5 tons ha<sup>-1</sup>. A factorial, completely randomized design was used in this research.</div>

<div style="text-align: left;"><br />
<strong>Result:</strong> Water stress and organic amendments affect total stomata, leaf curl, leaf area, proline content, shoot and root dry weight, shoot-root ratio and biomass production of corn. Applying organic amendments increases corn&rsquo;s resistance to water stress, indicated by decreased plant proline content and increased biomass. The proline content of corn by application of organic amendment with rice straw 5 tons ha<sup>-1</sup> + biochar 5 tons ha<sup>-1</sup> (70.41 &micro; mol/g) was lower than the proline content of treatment without amendments (93.69 &micro; mol/g). NK-Jumbo was the most resistant variety to water stress conditions.</div>
</div>


<p>Effect of Organic Amendments on the Water Stress Resistance of Corn Varieties during Vegetative Stage in Ultisols</p>


<p style="text-align: justify;">Water deficit is undoubtedly one of the most important environmental stresses limiting the productivity of chickpea around the world. Exogenous application of bioregulators has been found to be a novel technology for imparting stress tolerance in crop plants. This study evaluated the changes brought about by two bioregulators viz., thiourea (TU) and thidiazuron (TDZ) under water deficit stress in chickpea leaf anatomy, chloroplast ultrastructure and photosynthesis. The experiment was conducted using Pusa 362 (Desi type) chickpea variety. Imposed water deficit treatment decreased relative water content (RWC), membrane stability index (MSI) and photosynthetic rate (PN). However, bioregulators application maintained higher RWC, MSI and PN under water deficit stress. Under imposed water stress, compact palisade layers of the mesophyll tissue were disrupted and cell size of the mesophyll cells displayed drastic reduction. Chloroplast, under water stress, displayed a number of grana with lose type of thylakoid, large increase in osmiophillic granules, reduction in the amount of starch granules and overall disruption of the thylakoid membrane. Foliar application of bioregulators maintained the integrity of mesophyll tissue and chloroplast structure thereby protected the chickpea plants from the detrimental effects of water deficit stress.&nbsp;</p>


Application of Nanobiotechnology in Enabling Plants to Overcome Water-logging Stress: A Review

Effect of PEG mediated water stress on solute accumulation, relative water content, biomass and antioxidant enzymes in rice

Root-based Responses of Well-watered and Water-stressed Chickpea (Cicer arietinum L.) Genotypes Varying for Drought Tolerance and Biomass

Effect of Water Stress on Growth and Root Characteristics of Lentil

Physiological Characterization of Pigeon Pea Genotypes [Cajanus cajan (L) Mill sp.] for Water Logging Tolerance

Plant Metabolism during Water Deficit Stress: A Review

Studies on the Effect of Water Stress on Root Traits in Green Gram Cultivars

Growth and Yield Performance of Wheat (Triticum aestivum L.) to under Water Stress Conditions

Effect of Organic Amendments on the Water Stress Resistance of Corn Varieties during Vegetative Stage in Ultisols

Bioregulators protected the leaf anatomy and photosynthetic machinery under water deficit stress in chickpea (Cicer arietinum L.)