scholarly journals Unravelling the Role of Piriformospora indica in Combating Water Deficiency by Modulating Physiological Performance and Chlorophyll Metabolism-Related Genes in Cucumis sativus

Horticulturae ◽  
2021 ◽  
Vol 7 (10) ◽  
pp. 399
Author(s):  
Mohamed E. Abdelaziz ◽  
Mohamed A. M. Atia ◽  
Mohamed Abdelsattar ◽  
Suzy M. Abdelaziz ◽  
Taha A. A. Ibrahim ◽  
...  
Keyword(s):  
Water Stress ◽  
Chlorophyll A ◽  
Irrigation Water ◽  
Chlorophyll Biosynthesis ◽  
Stomatal Closure ◽  
Stress Conditions ◽  
Piriformospora Indica ◽  
Activity Levels ◽  
Chlorophyll Metabolism ◽  
Severe Water Stress

Water stress is the most critical aspect restricting the development of agriculture in regions with scarce water resources, which requires enhancing irrigation water-saving strategies. The current work discusses the potential application of the plant-strengthening root endophyte Piriformospora indica against moderate (25% less irrigation water) and severe (50% less irrigation water) water stress in comparison to the optimum irrigation conditions of greenhouse cucumbers. P. indica improved growth, nutrient content, and photosynthesis apparatus under normal or water-stress conditions. On the other hand, moderate and severe water stress reduced yield up to 47% and 83%, respectively, in non-colonized cucumber plants, while up to 28 and 78%, respectively, in P. indica-colonized plants. In terms of water-use efficiency (WUE), P. indica improved the WUE of colonized cucumber plants grown under moderate (26 L/kg) or severe stress (73 L/kg) by supporting colonized plants in producing higher yield per unit volume of water consumed by the crop in comparison to non-colonized plants under the same level of moderate (43 L/kg) or severe (81 L/kg) water stress. Furthermore, P. indica increased the indole-3-acetic acid (IAA) content, activity levels of catalase (CAT) and peroxidase (POD) with an apparent clear reduction in the abscisic acid (ABA), ethylene, malondialdehyde (MDA), proline contents and stomatal closure compared to non-stressed plants under both water-stress levels. In addition, chlorophyll a, b, a + b contents were increased in the leaves of the colonized plants under water-stress conditions. This improvement in chlorophyll content could be correlated with a significant increment in the transcripts of chlorophyll biosynthesis genes (protochlorophyllide oxidoreductase [POR], chlorophyll a oxygenase [CAO]) and a reduction in the chlorophyll degradation genes (PPH, pheophorbide a oxygenase [PAO], and red chlorophyll catabolite reductase [RCCR]). In conclusion, P. indica has the potential to enhance the cucumber yield grown under moderate water stress rather than severe water stress by improving WUE and altering the activity levels of antioxidant enzymes and chlorophyll metabolism-related genes.

Single hyperspectral bands are highly sensitive to water stress in adult mandarin trees

2021 ◽  
Author(s):  
Pablo Berríos ◽  
Abdelmalek Temnani ◽  
Susana Zapata ◽  
Manuel Forcén ◽  
Sandra Martínez-Pedreño ◽  
...  
Keyword(s):  
Water Stress ◽  
Water Deficit ◽  
Phase Ii ◽  
Irrigation Water ◽  
Water Status ◽  
Irrigation Scheduling ◽  
Plant Water Status ◽  
Phase Iii ◽  
Plant Water ◽  
Severe Water Stress

<p>Mandarin is one of the most important Citrus cultivated in Spain and the sustainability of the crop is subject to a constant pressure for water resources among the productive sectors and to a high climatic demand conditions and low rainfall (about 250 mm per year). The availability of irrigation water in the Murcia Region is generally close to 3,500 m<sup>3</sup> per ha and year, so it is only possible to satisfy 50 - 60% of the late mandarin ETc, which requires about 5,500 m<sup>3</sup> per ha. For this reason, it is necessary to provide tools to farmers in order to control the water applied in each phenological phase without promoting levels of severe water stress to the crop that negatively affect the sustainability of farms located in semi-arid conditions. Stem water potential (SWP) is a plant water status indicator very sensitive to water deficit, although its measurement is manual, discontinuous and on a small-scale.  In this way, indicators measured on a larger scale are necessary to achieve integrating the water status of the crop throughout the farm. Thus, the aim of this study was to determine the sensitivity to water deficit of different hyperspectral single bands (HSB) and their relationship with the midday SWP in mandarin trees submitted to severe water stress in different phenological phases. Four different irrigation treatments were assessed: i) a control (CTL), irrigated at 100% of the ETc throughout the growing season to satisfy plant water requirements and three water stress treatments that were irrigated at 60% of ETc throughout the season – corresponding to the real irrigation water availability – except  during: ii) the end of phase I and beginning of phase II (IS IIa), iii) the first half of phase II (IS IIb) and iv) phase III of fruit growth (IS III), which irrigation was withheld until values of -1.8 MPa of SWP or a water stress integral of 60 MPa day<sup>-1</sup>. When these threshold values were reached, the spectral reflectance values were measured between 350 and 2500 nm using a leaf level spectroradiometer to 20 mature and sunny leaves on 4 trees per treatment. Twenty-four HVI and HSB were calculated and a linear correlation was made between each of them with SWP, where the ρ940 and ρ1250 nm single bands reflectance presented r-Pearson values of -0.78** and -0.83***, respectively. Two linear regression curves fitting were made: SWP (MPa) = -11.05 ∙ ρ940 + 7.8014 (R<sup>2</sup> =0.61) and SWP (MPa) = -13.043 ∙ ρ1250 + 8.9757 (R<sup>2</sup> =0.69). These relationships were obtained with three different fruit diameters (35, 50 and 65 mm) and in a range between -0.7 and -1.6 MPa of SWP. Results obtained show the possibility of using these single bands in the detection of water stress in adult mandarin trees, and thus propose a sustainable and efficient irrigation scheduling by means of unmanned aerial vehicles equipped with sensors to carry out an automated control of the plant water status and with a suitable temporal and spatial scale to apply precision irrigation.</p>

scholarly journals Evaluation of some pepper genotypes as rootstocks in water stress conditions

2014 ◽  
Vol 41 (No. 4) ◽  
pp. 192-200 ◽  
Author(s):  
C. Penella ◽  
S.G. Nebauer ◽  
S. López-Galarza ◽  
A. SanBautista ◽  
A. Rodríguez-Burruezo ◽  
...  
Keyword(s):  
Water Stress ◽  
Net Photosynthetic Rate ◽  
Water Scarcity ◽  
Crop Production ◽  
Stress Conditions ◽  
Photosynthetic Parameters ◽  
Crop Varieties ◽  
Severe Water Stress ◽  
Pepper Cultivar ◽  
Grafting Onto

 Water stress is a major environmental factor that limits crop production and it is important to develop crop varieties with higher yield under water scarcity. Increased pepper tolerance to water stress through grafting onto robust rootstocks could be an optimal alternative in the context of environmentally friendly agriculture. Our work evaluated the behaviour of 18 pepper genotypes during vegetative and reproductive stages under water stress in order to select tolerant genotypes to be used as rootstocks for pepper cultivation. The pepper tolerance screening was based on photosynthetic parameters. The genotypes Atlante, C-40, Serrano, PI-152225, ECU-973, BOL-58 and NuMex Conquistador were revealed as the most tolerant genotypes to water stress because they maintained net photosynthetic rate levels under water stress conditions. The selected genotypes were validated as rootstocks on a pepper cultivar in terms of productivity under severe water stress. Plants grafted onto cvs Atlante, PI-152225 and ECU-973 showed higher marketable yields when compared with ungrafted cultivar.  

scholarly journals Growth and carbon assimilation limitations in Ricinus communis (Euphorbiaceae) under soil water stress conditions

2010 ◽  
Vol 24 (3) ◽  
pp. 648-654 ◽  
Author(s):  
Tanise Luisa Sausen ◽  
Luís Mauro Gonçalves Rosa
Keyword(s):  
Water Stress ◽  
Soil Water ◽  
Drought Resistance ◽  
Ricinus Communis ◽  
Stomatal Closure ◽  
Carbon Assimilation ◽  
Stress Conditions ◽  
Carbon Gain ◽  
Resistant Species ◽  
Ricinus Communis L

Water availability may influence plant carbon gain and growth, with large impacts on plant yield. Ricinus communis (L.), a drought resistant species, is a crop with increasing economic importance in Brazil, due to its use in chemical industry and for the production of biofuels. Some of the mechanisms involved in this drought resistance were analyzed in this study by imposing progressive water stress to pot-grown plants under glasshouse conditions. Water withholding for 53 days decreased soil water gravimetric content and the leaf water potential. Plant growth was negatively and significantly reduced by increasing soil water deficits. With irrigation suspension, carbon assimilation and transpiration were reduced and remained mostly constant throughout the day. Analysis of A/Ci curves showed increased stomatal limitation, indicating that limitation imposed by stomatal closure is the main factor responsible for photosynthesis reduction. Carboxylation efficiency and electron transport rate were not affected by water stress up to 15 days after withholding water. Drought resistance of castor bean seems to be related to a pronounced, early growth response, an efficient stomatal control and the capacity to keep high net CO2 fixation rates under water stress conditions.

Effect of endophytic fungus Piriformospora indica on yield and some physiological traits of millet (Panicum miliaceum) under water stress

2018 ◽  
Vol 69 (6) ◽  
pp. 594 ◽  
Author(s):  
Goudarz Ahmadvand ◽  
Somayeh Hajinia
Keyword(s):  
Water Stress ◽  
Grain Yield ◽  
Leaf Area ◽  
Water Deficit ◽  
Flag Leaf ◽  
Piriformospora Indica ◽  
Physiological Traits ◽  
Water Deficit Stress ◽  
Panicum Miliaceum ◽  
Severe Water Stress

Piriformospora indica is one of the cultivable root-colonising endophytic fungi of the order Sebacinales, which efficiently promote plant growth, uptake of nutrients, and resistance to biotic and abiotic stresses. The aim of this study was to evaluate the effect of P. indica on millet (Panicum miliaceum L.) under water-stress conditions. Two field experiments were carried out in a factorial arrangement at Bu-Ali Sina University of Hamedan, Iran, during 2014 and 2015. The first factor was three levels of water-deficit stress, with irrigation after 60 mm (well-watered), 90 mm (mild stress) and 120 mm (severe stress) evaporation from pan class A. The second factor was two levels of fungus P. indica: inoculated and uninoculated. Results showed that water-deficit stress significantly decreased grain yield and yield components. Colonisation by P. indica significantly increased number of panicles per plant, number of grains per panicle and 1000-grain weight, regardless of water supply. Inoculation with P. indica increased grain yield by 11.4% (year 1) and 19.72% (year 2) in well-watered conditions and by 35.34% (year 1) and 32.59% (year 2) under drought stress, compared with uninoculated plants. Maximum flag-leaf area (21.71 cm2) was achieved with well-watered conditions. Severe water stress decreased flag-leaf area by 53.36%. Flag-leaf area was increased by 18.64% by fungus inoculation compared with the uninoculated control. Under drought conditions, inoculation with P. indica increased plant height by 27.07% and panicle length by 9.61%. Severe water stress caused a significant decrease in grain phosphorus concentration, by 42.42%, compared with the well-watered treatment. By contrast, grain nitrogen and protein contents were increased about 30.23% and 30.18%, respectively, with severe water stress. Inoculation with P. indica increased grain phosphorus by 24.22%, nitrogen by 7.47% and protein content by 7.54% compared with control. Water stress reduced leaf chlorophyll and carotenoid concentrations, whereas P. indica inoculation enhanced chlorophyll concentrations by 27.18% under severe water stress. The results indicated the positive effect of P. indica on yield and physiological traits of millet in both well-watered and water-stressed conditions.

scholarly journals Short-Term Exposure to High Atmospheric Vapor Pressure Deficit (VPD) Severely Impacts Durum Wheat Carbon and Nitrogen Metabolism in the Absence of Edaphic Water Stress

Plants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 120
Author(s):  
Dorra Fakhet ◽  
Fermín Morales ◽  
Iván Jauregui ◽  
Gorka Erice ◽  
Pedro M. Aparicio-Tejo ◽  
...  
Keyword(s):  
Gene Expression ◽  
Water Stress ◽  
Vapor Pressure ◽  
Soil Water ◽  
Vapor Pressure Deficit ◽  
Stomatal Closure ◽  
Stress Conditions ◽  
Short Term Exposure ◽  
Young Leaves ◽  
N Metabolism

Low atmospheric relative humidity (RH) accompanied by elevated air temperature and decreased precipitation are environmental challenges that wheat production will face in future decades. These changes to the atmosphere are causing increases in air vapor pressure deficit (VPD) and low soil water availability during certain periods of the wheat-growing season. The main objective of this study was to analyze the physiological, metabolic, and transcriptional response of carbon (C) and nitrogen (N) metabolism of wheat (Triticum durum cv. Sula) to increases in VPD and soil water stress conditions, either alone or in combination. Plants were first grown in well-watered conditions and near-ambient temperature and RH in temperature-gradient greenhouses until anthesis, and they were then subjected to two different water regimes well-watered (WW) and water-stressed (WS), i.e., watered at 50% of the control for one week, followed by two VPD levels (low, 1.01/0.36 KPa and high, 2.27/0.62 KPa; day/night) for five additional days. Both VPD and soil water content had an important impact on water status and the plant physiological apparatus. While high VPD and water stress-induced stomatal closure affected photosynthetic rates, in the case of plants watered at 50%, high VPD also caused a direct impairment of the RuBisCO large subunit, RuBisCO activase and the electron transport rate. Regarding N metabolism, the gene expression, nitrite reductase (NIR) and transport levels detected in young leaves, as well as determinations of the δ15N and amino acid profiles (arginine, leucine, tryptophan, aspartic acid, and serine) indicated activation of N metabolism and final transport of nitrate to leaves and photosynthesizing cells. On the other hand, under low VPD conditions, a positive effect was only observed on gene expression related to the final step of nitrate supply to photosynthesizing cells, whereas the amount of 15N supplied to the roots that reached the leaves decreased. Such an effect would suggest an impaired N remobilization from other organs to young leaves under water stress conditions and low VPD.

scholarly journals Azospirillum brasilense affects the antioxidant activity and leaf pigment content of Urochloa ruziziensis under water stress

2016 ◽  
Vol 46 (3) ◽  
pp. 343-349 ◽  
Author(s):  
Lucas Guilherme Bulegon ◽  
Vandeir Francisco Guimarães ◽  
Jessica Cristina Urbanski Laureth
Keyword(s):  
Reactive Oxygen Species ◽  
Water Stress ◽  
Chlorophyll A ◽  
Azospirillum Brasilense ◽  
Photosynthetic Pigment ◽  
Reactive Oxygen ◽  
Pigment Content ◽  
Oxygen Species ◽  
Chlorophylls A And B ◽  
Severe Water Stress

ABSTRACT Water stress leads to the formation of reactive oxygen species, resulting in degradation of leaf pigments and cell death. This study aimed at assessing the oxidative enzyme activity and photosynthetic pigment content in seeds and/or leaves of Urochloa ruziziensis (syn. Brachiaria) inoculated with Azospirillum brasilense under water stress. Assessments of soluble proteins, chlorophylls a and b and carotenoid contents, as well as the activity of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) enzymes, were conducted at the beginning of the water stress process and also under severe water stress and during plant rehydration. Seed inoculation showed a reduction in the action of SOD, under water stress, with an increase after rehydration. POD exhibited an activity greater than CAT in all the assessments, but it did not differ statistically under severe water stress. CAT activity increased under severe stress in all treatments, particularly for leaf inoculation. Chlorophyll a was slightly degraded, maintaining the levels of the irrigated control, while the chlorophyll b and carotenoid contents, in plants subjected to leaf inoculation with A. brasilense, were higher under water stress. It was concluded that the leaf inoculation of U. ruziziensis with A. brasilense makes the plant more efficient at removing reactive oxygen species and protecting chlorophyll a.

scholarly journals EFFECTS OF WATER DEFICIT ON MAZE SEEDLINGS GROWTH TRAITS

2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
F Shafique ◽  
Q Ali ◽  
A Malik
Keyword(s):  
Water Stress ◽  
Drought Stress ◽  
Water Deficit ◽  
Irrigation Water ◽  
Stress Conditions ◽  
Growth And Yield ◽  
Maize Growth ◽  
Maize Genotypes ◽  
Maize Genotype ◽  
Maize Varieties

Many biotic and abiotic factors affect plant growth and its development. Maize growth usually increased under excess water availability but less tolerant against water deficit stress condition. In this study, we investigated the effects of water stress on the growth and yield of maize. We found that severe water stress during the seedling stage had a greater effect on the growth and development of maize. Three maize varieties (Pak afghoi, Neelum, White corn) were used to find out the effects on growth of plant under drought or water deficit environmental conditions. Different drought stress treatments (Control, 20% irrigation water, 40% irrigation water, 60% irrigation water, 80% irrigation water) were imposed to growing seedlings after germination. The treatments were applied after 4 times each after 7 days interval and data for different morphological traits was recorded each time. The recorded data was pooled and analyzed for analysis of variance to access the significance of results. The ANOVA indicated the differences among five different genotypes and 5 different treatments for all parameters were significant. Tukey’s test indicated that maize genotype White corn was more tolerant while genotype Neelum was more sensitive for drought stress conditions therefore, white corn maize genotype may be helpful for the development of drought tolerance maize varieties and hybrids. Positive and significant correlation was found for shoot length with all other studied traits under drought stress conditions. Treatment control, 80% and 60% irrigation water was less adverse for maize growth while treatment 20% irrigation water highly affected all maize genotypes, therefore maize genotypes may be grow under treatment 60% irrigation water.

ROOT CHARACTERISTICS IN COWPEA RELATED TO DROUGHT TOLERANCE AT THE SEEDLING STAGE

2003 ◽  
Vol 39 (1) ◽  
pp. 29-38 ◽  
Author(s):  
T. MATSUI ◽  
B. B. SINGH
Keyword(s):  
Water Stress ◽  
Drought Tolerance ◽  
Leaf Area ◽  
Dry Matter ◽  
Stress Conditions ◽  
Root Characteristics ◽  
Severe Water Stress ◽  
Cowpea Varieties ◽  
Root Box ◽  
Mild Water Stress

Cowpea (Vigna unguiculata) has relatively higher drought tolerance than other legume crops. It is widely grown in semi-arid regions, particularly in West Africa. One objective of the present study was to determine the effects of soil moisture stress on the length, dry matter and distribution of the roots of two cowpea varieties with different drought tolerances. Another objective was to evaluate the pin-board root-box as a method for identifying the role of root characteristics in drought tolerance. Two cowpea varieties, IT96D-604 (drought tolerant) and TVu7778 (drought susceptible), were used in this study. There were three watering treatments, T1 (well-watered), T2 (mild water stress) and T3 (severe water stress). Between varieties, there were no significant differences in shoot and root characteristics except for leaf area in T1. Under T2, the shoot:root ratio (S:R ratio) of IT96D-604 was significantly decreased compared with that under T1 as a result of the increase in root dry matter and decrease in leaf area without significant differences in total dry matter. In addition, the root dry matter per leaf area, which indicates the capacity to absorb water, of IT96D-604 was significantly higher than that of TVu7778. Under T3, the total dry matter of TVu7778 was about one third of those of the other treatments for the same variety, whereas that of IT96D-604 was more than half. Regarding root distribution, the centres of root dry matter and root length density of both varieties moved downwards significantly under water-stress conditions compared with those of the well-watered condition. This tendency was more pronounced in IT96D-604 than in TVu7778. Drought tolerance in IT96D-604 was associated with the increase in root dry matter per leaf area under mild water-stress conditions, and downward movement of roots (increasing access and use of soil moisture in deep soil layers) under mild and severe water stress conditions. In addition, the root-box method was versatile and can be used for studying root responses to edaphic factors relevant to root growth.

scholarly journals Enzymatic antioxidant responses to biostimulants in maize and soybean subjected to drought

2009 ◽  
Vol 66 (3) ◽  
pp. 395-402 ◽  
Author(s):  
Ana Carolina Feitosa de Vasconcelos ◽  
Xunzhong Zhang ◽  
Erik H. Ervin ◽  
Jorge de Castro Kiehl
Keyword(s):  
Reactive Oxygen Species ◽  
Superoxide Dismutase ◽  
Water Stress ◽  
Stomatal Closure ◽  
Activity Levels ◽  
Oxygen Species ◽  
Physiological Changes ◽  
Antioxidant Responses ◽  
Oxidative Processes ◽  
Soybean Plants

Water stress is one of the most important environmental factors inducing physiological changes in plants, such as decrease in the water potential of the cells, the stomatal closure; and the development of oxidative processes mediated by reactive oxygen species (ROS). Antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) are efficient scavengers of ROS. The aim of this research was to examine how the application of biostimulant based on humic substances and aminoacids may affect activity levels of SOD, CAT, and APX of maize and soybean plants under well-watered or drought stress conditions. Pots (4.5 L) were filled with a Typic Hapludult soil where the biostimulants doses were applied. It was taken leaf samples in order to analyze SOD, CAT, and APX activities in plants. SOD and APX activity levels were increased by application of biostimulant 1 in maize subjected to stress. Catalase activity was not enhanced in plants by using the biostimulants. The composition of the biostimulants was not able to enhance stress tolerance in maize and soybean plants subjected to water stress.

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