Influence of Different Typ es Mycorrhizal Fungi on Crop Productivity

Mycorrhizal fungi greatly enhanced the ability of plants to take up phosphorus and other nutrients those are relatively immobile and exist in low concentration in the soil solution. Fungi can be important in the uptake of other nutrients by the host plant. Zinc nutrition is most commonly reported as being influenced by the association, although uptake of copper (Cu) , iron, N, K, Ca and Mg has been reported to be enhanced. Water uptake may be improved by mycorrhizal association, making more resistant to drought condition. Often both water and nutrient uptake are higher in drought stressed mycorrhizal plants than in non mycorrhizal plants. The fungal strands are capable of altering the water potential of plants and can only alleviate moderate drought stress and in more severe drought conditions they become ineffective.

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Enhancement of drought tolerance in diverse Vicia faba cultivars by inoculation with plant growth-promoting rhizobacteria under newly reclaimed soil conditions

Scientific Reports ◽

10.1038/s41598-021-02847-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Elsayed Mansour ◽

Hany A. M. Mahgoub ◽

Samir A. Mahgoub ◽

El-Sayed E. A. El-Sobky ◽

Mohamed I. Abdul-Hamid ◽

...

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Plant Growth ◽

Plant Growth Promoting Rhizobacteria ◽

Severe Drought ◽

Drought Conditions ◽

Moderate Drought ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Effects Of Drought

AbstractWater deficit has devastating impacts on legume production, particularly with the current abrupt climate changes in arid environments. The application of plant growth-promoting rhizobacteria (PGPR) is an effective approach for producing natural nitrogen and attenuating the detrimental effects of drought stress. This study investigated the influence of inoculation with the PGPR Rhizobium leguminosarum biovar viciae (USDA 2435) and Pseudomonas putida (RA MTCC5279) solely or in combination on the physio-biochemical and agronomic traits of five diverse Vicia faba cultivars under well-watered (100% crop evapotranspiration [ETc]), moderate drought (75% ETc), and severe drought (50% ETc) conditions in newly reclaimed poor-fertility sandy soil. Drought stress substantially reduced the expression of photosynthetic pigments and water relation parameters. In contrast, antioxidant enzyme activities and osmoprotectants were considerably increased in plants under drought stress compared with those in well-watered plants. These adverse effects of drought stress reduced crop water productivity (CWP) and seed yield‐related traits. However, the application of PGPR, particularly a consortium of both strains, improved these parameters and increased seed yield and CWP. The evaluated cultivars displayed varied tolerance to drought stress: Giza-843 and Giza-716 had the highest tolerance under well-watered and moderate drought conditions, whereas Giza-843 and Sakha-4 were more tolerant under severe drought conditions. Thus, co-inoculation of drought-tolerant cultivars with R. leguminosarum and P. putida enhanced their tolerance and increased their yield and CWP under water-deficit stress conditions. This study showed for the first time that the combined use of R. leguminosarum and P. putida is a promising and ecofriendly strategy for increasing drought tolerance in legume crops.

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Effects of root phenotypic changes on the deep rooting of Populus euphratica seedlings under drought stresses

PeerJ ◽

10.7717/peerj.6513 ◽

2019 ◽

Vol 7 ◽

pp. e6513 ◽

Cited By ~ 2

Author(s):

Zi-qi Ye ◽

Jian-ming Wang ◽

Wen-juan Wang ◽

Tian-han Zhang ◽

Jing-wen Li

Keyword(s):

Drought Stress ◽

Root Architecture ◽

Mass Fraction ◽

Populus Euphratica ◽

Severe Drought ◽

Root Depth ◽

Phenotypic Changes ◽

Positive Effects ◽

Drought Conditions ◽

Moderate Drought

Background Deep roots are critical for the survival of Populus euphratica seedlings on the floodplains of arid regions where they easily suffer drought stress. Drought typically suppresses root growth, but P. euphratica seedlings can adjust phenotypically in terms of root-shoot allocation and root architecture and morphology, thus promoting deep rooting. However, the root phenotypic changes undertaken by P. euphratica seedlings as a deep rooting strategy under drought conditions remain unknown. Methods We quantified deep rooting capacity by the relative root depth (RRD), which represents the ratio of taproot length to plant biomass and is controlled by root mass fraction (RMF), taproot mass fraction (TRMF), and specific taproot length (STRL). We recorded phenotypic changes in one-year-old P. euphratica seedlings under control, moderate and severe drought stress treatments and assessed the effects of RMF, TRMF, and STRL on RRD. Results Drought significantly decreased absolute root depth but substantially increased RRD via exerting positive effects on TRMF, RMF, and STRL. Under moderate drought, TRMF contributed 55%, RMF 27%, and STRL 18% to RRD variation. Under severe drought, the contribution of RMF to RRD variation increased to 37%, which was similar to the 41% for TRMF. The contribution of STRL slightly increased to 22%. Conclusion These results suggest that the adjustments in root architecture and root-shoot allocation were predominantly responsible for deep rooting in P. euphratica seedlings under drought conditions, while morphological changes played a minor role. Moreover, P. euphratica seedlings rely mostly on adjusting their root architecture to maintain root depth under moderate drought conditions, whereas root-shoot allocation responds more strongly under severe drought conditions, to the point where it plays a role as important as root architecture does on deep rooting.

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Exogenous salicylic acid-induced drought stress tolerance in wheat (Triticum aestivum L.) grown under hydroponic culture

PLoS ONE ◽

10.1371/journal.pone.0260556 ◽

2021 ◽

Vol 16 (12) ◽

pp. e0260556

Author(s):

Ali Ahmad ◽

Zubair Aslam ◽

Maliha Naz ◽

Sadam Hussain ◽

Talha Javed ◽

...

Keyword(s):

Salicylic Acid ◽

Drought Stress ◽

Root Length ◽

Shoot Length ◽

Water Deficit Stress ◽

Wheat Crop ◽

Severe Drought ◽

Drought Condition ◽

Moderate Drought ◽

Mild Drought

Wheat is an important cereal crop, which is adversely affected by water deficit stress. The effect of induced stress can be reduced by the application of salicylic acid (SA). With the objective to combat drought stress in wheat, an experiment was conducted in greenhouse under hydroponic conditions. The treatments consisted of (a) no drought (DD0 = 0 MPa), mild drought (DD1 = -0.40 MPa) and severe drought (DD2 = -0.60 MPa) by applying PEG-8000, (b) two contrasting wheat varieties Barani-17 (drought tolerant) and Anaj-17 (drought-sensitive), and (c) foliar treatments of salicylic acid (0, 50 mM, 75 mM, and 100 mM). Evaluation of wheat plants regarding biochemical, physiological, and morphological attributes were rendered after harvesting of plants. Statistically, maximum shoot and root fresh and dry weights (18.77, 11.15 and 1.99, 1.81 g, respectively) were recorded in cultivar Barani-17 under no drought condition with the application of SA (100 mM). While, minimum shoot and root fresh and dry weights (6.65, 3.14 and 0.73, 0.61 g, respectively) were recorded in cultivar Anaj-2017 under mild drought stress without SA application. The maximum shoot length (68.0 cm) was observed in cultivar Barani-2017 under no drought condition with the application of SA (100 mM). While, maximum root length (59.67 cm) was recorded in cultivar Anaj-17 under moderate drought stress without application of SA. Further, minimum shoot length (28.67 cm) was recorded in Anaj-17 under moderate drought stress without SA application. Minimum root length (38.67 cm) was recorded in cultivar Barani-17 under no drought condition without SA application. Furthermore, maximum physio-biochemical traits, including membrane stability index (MSI), chlorophyl content, photosynthetic rates, stomatal conductance, antioxidant enzymatic activities and relative water content (RWC) were found highest in cultivar Barani-17 under no drought stress and SA application at 100 mM. However, minimum values of these traits were recorded in cultivar Anaj-17 under severe drought stress without SA application. Our results also demonstrated that under severe drought, application of SA at 100 mM significantly increased leaf nitrogen (N), phosphrus (P) and potassium (K) contents and cultivar Barani-17 demonstrated significantly higher values than Anaj-17. The obtained results also indicated that the cultivation of wheat under drought stress conditions noticeably declines the morphological, physiological, and biochemical attributes of the plants. However, the exogenous application of SA had a positive impact on wheat crop for enhancing its productivity.

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Phedimus Aizoon L. Responds to Drought Stress: Growth, Physiological Changes and Mechanism of Drought Resistance

10.21203/rs.3.rs-132688/v1 ◽

2020 ◽

Author(s):

Yuhang Liu ◽

Zhongqun He ◽

Yongdong Xie ◽

Lihong Su ◽

Ruijie Zhang ◽

...

Keyword(s):

Drought Stress ◽

Drought Resistance ◽

Soluble Sugar ◽

Severe Drought ◽

Physiological Changes ◽

Moderate Drought ◽

Negative Effect ◽

Mda Content ◽

Maximum Water ◽

Mild Drought

Abstract A pot experiment was conducted to investigate the growth, physiological changes and mechanism of drought resistance of Phedimus aizoon L. under different levels of water content .CK: 75% ~ 80% of the MWHC (maximum water holding capacity), Mild drought: 55% ~ 60%, Moderate drought: 40% ~ 45%, Severe drought: 20% ~ 25%.We observed that the plants grew normally in the first two treatments, even the mild drought promoted the growth of the roots. In the last two treatments, drought stress had a significant negative effect on plant growth, at the same time, Phedimus aizoon L. also made positive physiological response to cope with the drought: The aboveground part of the plant (leaf, plant height, stem diameter) was smaller, the waxy layer of the leaves was thickened, the stomata of the leaves were closed during the day, and only a few stomata were opened at night, which proved that the dark reaction cycle metabolism mode of the plant was transformed from C3 cycle to CAM pathway. The activity of antioxidant enzymes (SOD, POD and CAT) was continuously increased to alleviate the damage caused by drought. To ensure the relative stability of osmotic potential, the contents of osmoregulation substances such as proline, soluble sugar, soluble protein and trehalose increased correspondingly. But plants have limited regulatory power, with aggravation of drought stress degree and extension of stress time, the MDA content and electrolyte leakage of leaves increased continuously. Observed under electron microscope,the morphology of chloroplast and mitochondria changed and the membrane structure was destroyed. The plant's photosynthetic and respiratory mechanisms are destroyed and the plant gradually die.

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What is the Difference between the Response of Grass Pea (Lathyrus sativus L.) to Salinity and Drought Stress?—A Physiological Study

Agronomy ◽

10.3390/agronomy10060833 ◽

2020 ◽

Vol 10 (6) ◽

pp. 833 ◽

Cited By ~ 1

Author(s):

Barbara Tokarz ◽

Tomasz Wójtowicz ◽

Wojciech Makowski ◽

Roman J. Jędrzejczyk ◽

Krzysztof M. Tokarz

Keyword(s):

Drought Stress ◽

Crop Productivity ◽

Lathyrus Sativus ◽

Soil Drought ◽

Severe Drought ◽

Chemical Stress ◽

Plant Tolerance ◽

Grass Pea ◽

Physiological Level ◽

Lathyrus Sativus L

Understanding the mechanisms of plant tolerance to osmotic and chemical stress is fundamental to maintaining high crop productivity. Soil drought often occurs in combination with physiological drought, which causes chemical stress due to high concentrations of ions. Hence, it is often assumed that the acclimatization of plants to salinity and drought follows the same mechanisms. Grass pea (Lathyrus sativus L.) is a legume plant with extraordinary tolerance to severe drought and moderate salinity. The aim of the presented study was to compare acclimatization strategies of grass pea seedlings to osmotic (PEG) and chemical (NaCl) stress on a physiological level. Concentrations of NaCl and PEG were adjusted to create an osmotic potential of a medium at the level of 0.0, −0.45 and −0.65 MPa. The seedlings on the media with PEG were much smaller than those growing in the presence of NaCl, but had a significantly higher content percentage of dry weight. Moreover, the stressors triggered different accumulation patterns of phenolic compounds, soluble and insoluble sugars, proline and β-N-oxalyl-L-α,β-diamino propionic acid, as well as peroxidase and catalase activity. Our results showed that drought stress induced a resistance mechanism consisting of growth rate limitation in favor of osmotic adjustment, while salinity stress induced primarily the mechanisms of efficient compartmentation of harmful ions in the roots and shoots. Furthermore, our results indicated that grass pea plants differed in their response to drought and salinity from the very beginning of stress occurrence.

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Leaf morphology, photochemistry and water status changes in resprouting Quercus ilex during drought

Functional Plant Biology ◽

10.1071/fp04137 ◽

2005 ◽

Vol 32 (2) ◽

pp. 117 ◽

Cited By ~ 41

Author(s):

Karen Peña-Rojas ◽

Xavier Aranda ◽

Richard Joffre ◽

Isabel Fleck

Keyword(s):

Drought Stress ◽

Quercus Ilex ◽

Structural Characteristics ◽

Water Status ◽

Stomatal Closure ◽

Severe Drought ◽

Clear Cut ◽

Leaf Mass Area ◽

Relative Water ◽

Moderate Drought

Functional and morphological (structural) characteristics of Quercus ilex L. leaves under drought stress were studied in the forest and in a nursery. We compared undisturbed individuals (controls) with resprouts emerging after clear-cut or excision. When soil water availability was high, gas-exchange was similar in resprouts and controls, despite higher midday leaf water potential, midday leaf hydration and relative water content (RWC). In moderate drought, stomatal closure was found to limit photosynthesis in controls, and in severe drought non-stomatal limitations of photosynthesis were also greater than in resprouts. Leaf structure and chemical composition changed under drought stress. Leaves tended to be smaller in controls with increasing drought, and resprouts had larger leaves and lower leaf mass area (LMA). The relationship between nitrogen (N) content and LMA implied lower N investment in photosynthetic components in controls, which could be responsible for their increased non-stomatal limitation of photosynthesis. Changes were more apparent in leaf density (D) and thickness (T), components of LMA. Decreases in D were related to reductions in cell wall components: hemicellulose, cellulose and lignin. In resprouts, reduced D and leaf T accounted for the higher mesophyll conductance (gmes) to CO2 measured.

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Overexpression of MdATG8i Enhances Drought Tolerance by Alleviating Oxidative Damage and Promoting Water Uptake in Transgenic Apple

International Journal of Molecular Sciences ◽

10.3390/ijms22115517 ◽

2021 ◽

Vol 22 (11) ◽

pp. 5517

Author(s):

Xin Jia ◽

Xiaoqing Gong ◽

Xumei Jia ◽

Xianpeng Li ◽

Yu Wang ◽

...

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Oxidative Damage ◽

Water Uptake ◽

Transcript Level ◽

Root Water Uptake ◽

Plant Responses ◽

Severe Drought ◽

Root Hydraulic Conductivity ◽

Drought Conditions

Water deficit adversely affects apple (Malus domestica) productivity on the Loess Plateau. Autophagy plays a key role in plant responses to unfavorable environmental conditions. Previously, we demonstrated that a core apple autophagy-related protein, MdATG8i, was responsive to various stresses at the transcript level. Here, we investigated the function of this gene in the response of apple to severe drought and found that its overexpression (OE) significantly enhanced drought tolerance. Under drought conditions, MdATG8iOE apple plants exhibited less drought-related damage and maintained higher photosynthetic capacities compared with the wild type (WT). The accumulation of ROS (reactive oxygen species) was lower in OE plants under drought stress and was accompanied by higher activities of antioxidant enzymes. Besides, OE plants accumulated lower amounts of insoluble or oxidized proteins but greater amounts of amino acids and flavonoid under severe drought stress, probably due to their enhanced autophagic activities. Particularly, MdATG8iOE plants showed higher root hydraulic conductivity than WT plants did under drought conditions, indicating the enhanced ability of water uptake. In summary, the overexpression of MdATG8i alleviated oxidative damage, modulated amino acid metabolism and flavonoid synthesis, and improved root water uptake, ultimately contributing to enhanced drought tolerance in apple.

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Foliar Sprayed Green Zinc Oxide Nanoparticles Mitigate Drought-Induced Oxidative Stress in Tomato

Plants ◽

10.3390/plants10112400 ◽

2021 ◽

Vol 10 (11) ◽

pp. 2400

Author(s):

Manal El-Zohri ◽

Naseem A. Al-Wadaani ◽

Sameera O. Bafeel

Keyword(s):

Oxidative Stress ◽

Zinc Oxide ◽

Drought Stress ◽

Zinc Oxide Nanoparticles ◽

Foliar Spray ◽

Oxide Nanoparticles ◽

Severe Drought ◽

Zno Nps ◽

Drought Conditions ◽

Tomato Growth

This study explored the effectiveness of green zinc oxide nanoparticles (ZnO-NPs) foliar spray on tomato growth and oxidative stress relief under drought conditions. Tomato plant subjected to four water regimes (100, 75, 50, and 25% FC), and in the same while seedlings were sprayed with 25, 50, and 100 mg/L green ZnO-NPs. The results showed that tomato growth parameters reduced significantly by increasing drought stress levels, while ZnO-NPs enhanced plant growth under all studied drought levels. Out of three ZnO-NPs concentrations tested, 25 and 50 mg/L ZnO-NPs proved to be the optimum treatments for alleviating drought stress. They increased shoot and root biomass compared to untreated controls. Application of 25 and 50 mg/L ZnO-NPs enhanced shoot dry weight by about 2–2.5-fold, respectively, under severe drought conditions (25%) compared to ZnO-NPs untreated plants. The application of 25 and 50 mg/L green ZnO-NPs decreased the drought-induced oxidative stress as indicated by the reduction in malondialdehyde and hydrogen peroxide concentrations compared to untreated controls. While 100 mg/L ZnO-NPs further increased oxidative stress. The beneficial effects of ZnO-NPs were evident in the plants’ defensive state, in which the concentration of ascorbic acid, free phenols, and the activity of superoxide dismutase, catalase, and ascorbate peroxidase were maintained at higher levels compared to NPs-untreated plants. At severe drought conditions, 25 mg/L ZnO-NPs induced SOD, CAT, and APX activity by about 3.99-, 3.23-, and 2.82-fold of their corresponding controls, respectively. Likewise, at 25% FC, SOD, CAT, and APX activity increased with 50 mg/L ZnO-NPs by about 4.58-, 3.57-, and 3.25-fold consecutively compared with their respective controls. Therefore, foliar use of green ZnO-NPs at lower concentrations might be suggested as an efficient way for enhancing tomato tolerance to drought stress.

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The Effect of Potassium Addition on Oil Palm (Elaeis guineensis Jacq.) Roots Anatomic Properties under Drought Stress

Caraka Tani Journal of Sustainable Agriculture ◽

10.20961/carakatani.v35i1.32578 ◽

2020 ◽

Vol 35 (1) ◽

pp. 54

Author(s):

Wiski Irawan ◽

Eka Tarwaca Susila Putra

Keyword(s):

Drought Stress ◽

Oil Palm ◽

Elaeis Guineensis ◽

Block Design ◽

Field Capacity ◽

Limiting Factors ◽

Severe Drought ◽

Cell Width ◽

K Fertilizer ◽

Moderate Drought

The availability of water is one of the main limiting factors for oil palm growth and production. Potassium (K) is an essential nutrient for plants because of its role in controlling metabolic and physiological activities. This study aimed to examine the effect of different K fertilizer doses on root anatomic properties under drought stress. The experiment was arranged in factorial Randomized Complete Block Design (RCBD) with two factors. The first factor was drought stress, consisting of three levels of fractions of transpirable soil water (FTSW) (FTSW 1 (control: field capacity); FTSW 0.35 (moderate drought); FTSW 0.15 (severe drought)) and the second factor was K dose (sourced from KCl), consisting of five levels (K0: 0%; K1: 50%; K2: 100%; K3: 150%; K4: 200%). The results showed that there was an interaction between the addition of K doses and the tolerance level of oil palm plants to drought stress. The addition of 100% K gave higher results in the parameters of xylem diameter, phloem diameter and cortex cell width compared to the plants without K. The results disclosed that 200% K application on moderate drought stress and severe drought stress in oil palm seedlings could widen xylem diameter, phloem diameters, strengthen cell such as epidermal cells, cortex cells, thickness of endodermic cells, thickness of sclerenchyma cells and increase hardness of cell compared to field capacity. As for the parameters of thick endodermic cells, stele diameter and sclerenchyma diameter, an addition of 50% K could give higher results.

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Computational Analysis for Rainfall Characterization and Drought Vulnerability in Peninsular India

Mathematical Problems in Engineering ◽

10.1155/2021/5572650 ◽

2021 ◽

Vol 2021 ◽

pp. 1-27

Author(s):

M. P. Akhtar ◽

Firoz Alam Faroque ◽

L. B. Roy ◽

Mohd. Rizwanullah ◽

Mukesh Didwania

Keyword(s):

Tamil Nadu ◽

Drought Index ◽

Extreme Drought ◽

Annual Rainfall ◽

Drought Indices ◽

Severe Drought ◽

Drought Vulnerability ◽

Drought Conditions ◽

Moderate Drought ◽

Standard Deviations

This paper analyzes the historical rainfall characterization and drought conditions in two major southern states of India, namely, Tamil Nadu and Karnataka, through estimation of meteorological drought indices, namely, drought index (DI), Palmer drought index (PDI), and standardized precipitation index (SPI). Monthly and yearly rainfall data, including temperature, have been considered for 110 years. Deficient rainfall conditions have been identified and compared using annual rainfall classification thresholds. Annual rainfall variability and trend have been estimated using Mann–Kendall test and Sen’s slope test. Comparative study on results implies that drought characterization using SPI may amply facilitate the standardization of threshold classification for severity and frequency. Based on threshold classification, it is found that Tamil Nadu witnessed on an average 11 years of moderate drought, 4.36 years of severe drought, and 1.32 years of extreme drought conditions with standard deviations of 4.28, 1.87, and 1.63 years, respectively, during the study period, whereas Karnataka witnessed on an average 9.74 years of moderate drought, 3.91 years of severe drought, and 2.30 years of extreme drought conditions with standard deviations of 4.54, 2.04, and 2.21 years, respectively, during the study period. According to the analysis, drought vulnerability in Tamil Nadu was higher than in Karnataka, based on the number of dry and wet years in terms of SPI threshold values and area covered over 110 years. Karnataka was more susceptible in terms of severity. When compared with other indices, analysis based on drought indices indicates that a single variable-based estimation using SPI is easy to assess and may be significant and definitive in terms of decision making for prioritizing drought mitigation measures in the study area in case of inadequate available data for multiple variable-based drought analysis.

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