Membrane Stability Index Research Articles

Effect of salicylic acid seed priming on morpho-physiological responses and yield of baby corn under salt stress

Rising salinity in the arable lands is a substantial threat to crop production. Exogenously-applied salicylic acid (SA) alleviates the negative impacts of salinity on plants. A factorial pot experiment, consisted of two baby corn hybrid cultivars (PAC 571: salt-tolerant and SG 17 Super: salt-sensitive), three doses of SA (0 [hydropriming], 1, and 2 mM) applied as a seed priming material, and four levels of salinity (0.7 [control], 6, 9, and 12 dS m–1), was conducted to evaluate the impact of SA on baby corn under salt stress. Data on growth, physiological traits, cob yield, and ion content in leaf tissues were collected, which revealed that an increasing salinity level was equally detrimental for the two tested cultivars with varying intensities. At the highest salinity level (12 dS m–1), both cultivars produced no cob, and the same salinity level caused a reduction of 67%, 14%, 42%, 87%, and 37% in shoot dry matter, leaf relative water content, membrane stability index, net photosynthetic rate, and leaf potassium content, respectively, compared with the control across cultivars and SA levels. The same salinity level caused about 3-fold, 10-fold, and 6-fold increases in electrolyte leakage, free proline content, and leaf sodium content, respectively. Seed priming with SA was effective, and 1 mM provided more promising results with an increase of 43%, 45%, 5%, and 7% in root dry matter, cob yield, leaf relative water content, and free proline content at 6 dS m–1 than 0 mM SA at the same salinity level. Salt-tolerant cultivar (PAC 571) had significantly higher cob number plant–1 (30%) and cob yield (34%) than salt-sensitive cultivar (SG 17 Super) at 6 dS m–1. However, there was largely no effect of SA seed priming on other evaluated parameters at 9 and 12 dS m–1 salinity levels. Priming of seeds with 1 mM SA could be a promising approach for baby corn production under a moderate salinity level up to 6 dS m–1. However, harmful effects of extreme salinity (9 and 12 dS m–1) cannot be completely compensated for SA seed priming.

Enhancement in Okra (Abelmoschus esculentus) Growth Performance Under Salt Stress Using Exogeneous Application of L- tryptophan

Salinity is one of the major stress factors that has a substantial impact on agricultural resilience and concerns global food safety. L-tryptophan being an essential regulator with specialized activities in plant functioning, as well as an increase in tolerance to various abiotic stressors. A hydroponic experiment was carried out to determine the effective role of L-tryptophan in okra seedlings in saline environment in terms of growth, physiological, ionic, and antioxidant properties. Salinity was imposed in growth medium with two levels of NaCl (Control and 80 mM NaCl) whereas one level of L-tryptophan (50 µM L-1) administered externally in both combined and single forms. MDA and H2O2 contents increase while plant dry matter, chlorophyll content, relative water contents, membrane stability index, K+/Na+ ratio decreases due to salt stress. Salt toxicity was reduced when L-tryptophan was added as illustrated by increased relative water contents, membrane stability index, K+/Na+ ratio, as well as suppression of MDA and H2O2 generation. Our findings suggested that L-tryptophan increased salinity tolerance in okra, which could be a cause of viable sustainable production from salt-affected soils.

Effects of Benzyl adenine (BA) and Gibberellic acid (GA3) on physiological and biochemical attributes of gladiolus (Gladiolus grandiflorus L.) spikes

The uniform sized corms (3.5-4.0 cm dia) of Gladiolus grandiflorus L. were dipped in various concentrations of BA (50,75, 100 and 125 mg/l) and GA3 (50 , 75 , 100 and 125 mg/l) for 24 hrs. The Membrane stability index (MSI), Relative water content (RWC), total soluble sugars and total protein content of florets increased with the increased concentrations of BA and GA3. The post harvest quality parameters also improved with BA and GA3 treatments as compared to control but GA3 had more significant effect than BA. The treatment with 125 mg/l GA3 significantly hastened the opening of basal floret, increased the floret size, number of florets open at one time, per cent of opening of florets, water absorbed and led to maximum reduction in pH that ultimately led to improvement in vase life. Bangladesh J. Bot. 51(2): 297-304, 2022 (June)

Evaluation of Post-harvest Quality of Marigold Flowers After Packaging and Storage in Different Seasons

In the present study, the keeping quality of differently packed and stored marigold flowers was evaluated under ambient conditions during summer and rainy seasons. The shelf life of marigold was 1 day in summer and 4 days in rainy season which was supported by high membrane stability index, relative water content, total soluble proteins, total soluble sugars, lesser loss in physiological weight, minimum spoilage and maximum freshness index of flowers in rainy season. The ice box, CFB box and polythene packages showed better results in comparison to gunny bag and onion mesh bag. One day storage was better in comparison to two and three days in all the seasons. Thus, marigold flowers can be packed in ice box, CFB box and polythene for 2 to 3 days without any adverse effect on keeping quality during rainy season. Bangladesh J. Bot. 51(2): 247-254, 2022 (June)

Ameliorating effect of vermicompost on Foeniculum vulgare under saline condition

Fennel (Foeniculum vulgare Mill) is a medicinal plant that all parts of it can be used in various industries such as food, chemical and pharmaceutical industries. To investigate the effect of vermicompost (VC: 0 and 5%), as an organic fertilizer, on the morphophysiological and biochemical characteristics of two fennel landraces (Shiraz and Urmia) under saline conditions (0, 40, 80, and 120 mM NaCl), a factorial experiment was conducted in greenhouse condition. After 3 weeks of culturing, plants were irrigated with experimental treatments until 5 weeks more. The results showed that salinity stress induced a significant decrease in leaf area, biomass, photosynthetic pigments content, relative water content, membrane stability index, minerals (Fe, K, Ca, and Mg) concentration, total protein content, and gibberellin concentration of the shoot. A significant increase in malondialdehyde, total phenol, and the activity of catalase and peroxidase enzymes in the same organ was also observed. In contrast, for most of these variables, the opposite results were obtained under VC alone or its interaction with salinity stress. In comparison between two fennel landraces, Shiraz was less affected by salinity stress, while the effect of VC on Urmia was more evident. It can be concluded that VC can limit the adverse effects of salinity stress on fennel by affecting photosynthetic pigments, membrane integrity, minerals concentration, water status, protein content, gibberellins biosynthesis, and antioxidants activity.

Genome-wide identification, in silico characterization and expression analysis of the RNA helicase gene family in chickpea (C. arietinum L.)

The RNA helicases are an important class of enzymes which are known to influence almost every aspect of RNA metabolism. The majority of RNA helicases belong to the SF2 (superfamily 2) superfamily, members of which are further categorized into three separate subfamilies i.e., the DEAD, DEAH and DExD/H-box subfamilies. In chickpea, these RNA helicases have not been characterized until now. A genome-wide analysis across the chickpea genome led to the identification of a total of 150 RNA helicase genes which included 50 DEAD, 33 DEAH and 67 DExD/H-box genes. These were distributed across all the eight chromosomes, with highest number on chromosome 4 (26) and least on chromosome 8 (8). Gene duplication analysis resulted in identification of 15 paralogous gene pairs with Ka/Ks values < 1, indicating towards the genes being under purifying selection during the course of evolution. The promoter regions of the RNA helicase genes were enriched in cis-acting elements like the light and ABA-responsive elements. The drought responsiveness of the genes was analysed by studying the expression profiles of few of these genes, in two different genotypes, the cultivated variety ICC 8261 (kabuli, C. arietinum) and the wild accession ILWC 292 (C. reticulatum), through qRT-PCR. These genotypes were selected based on their drought responsiveness in a field experiment, where it was observed that the percentage (%) reduction in relative water content (RWC) and membrane stability index (MSI) for the drought stressed plants after withholding water for 24 days, over the control or well-watered plants, was least for both the genotypes. The genes CaDEAD50 and CaDExD/H66 were identified as drought-responsive RNA helicase genes in chickpea. The protein encoded by the CaDExD/H66 gene shares a high degree of homology with one of the CLSY (CLASSY) proteins of A. thaliana. We hypothesize that this gene could possibly be involved in regulation of DNA methylation levels in chickpea by regulating siRNA production, in conjunction with other proteins like the Argonaute, RNA dependent RNA polymerases and Dicer-like proteins.

Salicylic Acid Enhances the Vase Life and Improves the Postharvest Attributes ¬¬— A Case Study of Antirrhinum majus L.

Antirrhinum majus L. is one of the most significant ornamental plants in the international flower industry, but has a relatively limited vase life, as evidenced by petal abscission and flower spike bending. The current study focuses on examining the efficacy of salicylic acid on the vase life and postharvest attributes of A. majus flower spikes. The spikes with the oldest floral bud at one day before anthesis stage were harvested and divided into 4 sets, with one set of spikes held in distilled water (DW) designated as control. The remaining three sets were supplemented with various concentrations of SA viz., 1, 2 and 3 mM. Among the concentrations studied, 2 mM was found to be the most promising SA concentration for increasing the postharvest performance of flowers of A. majus cut spikes. The enhanced vase life of A.majus spikes was characterised by increased floral diameter, a higher membrane stability index and elevated levels of total phenols and sugars as compared to the control. SA has been proven to suppress protein degradation and lipoxygenase activity during the vase life of flower spikes. Furthermore, SA-treated flower spikes with enhanced postharvest properties were shown to have higher levels of antioxidant enzymes such as superoxide dismutase, catalase and ascorbate peroxidase activity.

Soil Microorganisms and Seaweed Application With Supplementary Irrigation Improved Physiological Traits and Yield of Two Dryland Wheat Cultivars.

To evaluate the effect of useful soil microorganisms and organic compounds on physiological characteristics and yield of two wheat cultivars under supplementary irrigation conditions, a study was conducted in the Agriculture Research Farm of Kurdistan University during the two cropping seasons of 2017–2018 and 2018–2019. A split–split plot-based study on a randomized complete block design with four replicates was used as an experimental design. The main factor was irrigation at three levels, including control without irrigation, supplementary irrigation in the booting stage, and supplementary irrigation in the booting and flowering stages. Two wheat cultivars, namely, Sardari and Sirvan, as sub-factors and application of bio-fertilizers in eight levels, including the use of bio-fertilizers containing: Mycorrhiza, Seaweed extract, Nitrozist and Phosphozist, Mycorrhiza + Nitrozist and Phosphozist, Seaweed extract + Nitrozist and Phosphozist, Mycorrhiza + Seaweed extract, Mycorrhiza + Nitrozist and Phosphozist + Seaweed extract, and non-application of bio-fertilizers, were considered as sub-factors. The results of both seasons of the experiment showed that the application of bio-fertilizers compared to the control treatment at all irrigation levels increased root volume, leaf relative water content (RWC), membrane stability index (MSI), and photosynthetic pigment content. The highest amount of H2O2, proline, and soluble carbohydrates were obtained in wheat under dry land conditions, and supplementary irrigation, especially two-time irrigation, significantly reduced the values of these traits. Supplementary irrigation also increased grain yield, so that in the conditions of two-time irrigation compared to the non-irrigation treatment (dry land), in the first and second seasons, the grain yield increased by 79.51 and 78.69%, respectively. Application of bio-fertilizers (Mycorrhiza + Nitrozist and Phosphozist + Seaweed extract) in comparison with the non-application of these fertilizers, due to increased root volume, RWC, MSI, and content of photosynthetic pigments, increased the grain yield in the first and second seasons of the experiment by 8.04 and 6.96%, respectively. As a result, suitable microorganisms and seaweed can improve wheat resistance mechanisms to water deficit, which along with using supplementary irrigation that saves water consumption improves plant growth and yield in areas faced with water shortage.

Folic Acid Confers Tolerance against Salt Stress-Induced Oxidative Damages in Snap Beans through Regulation Growth, Metabolites, Antioxidant Machinery and Gene Expression.

Although the effect of folic acid (FA) and its derivatives (folates) have been extensively studied in humans and animals, their effects are still unclear in most plant species, specifically under various abiotic stress conditions. Here, the impact of FA as a foliar application at 0, 0.1, and 0.2 mM was studied on snap bean seedlings grown under non-saline and salinity stress (50 mM NaCl) conditions. The results indicated that under salinity stress, FA-treated plants revealed a significant (p ≤ 0.05) increase in growth parameters (fresh and dry weight of shoot and root). A similar trend was observed in chlorophyll (Chl b), total chlorophyll, carotenoids, leaf relative water content (RWC), proline, free amino acids (FAA), soluble sugars, cell membrane stability index (CMSI), and K, Ca, and K/Na ratio compared to the untreated plants. In contrast, a significant decrease was observed in Na and salinity-induced oxidative damage as indicated by reduced H2O2 production (using biochemical and histochemical detection methods) and rate of lipid peroxidation (malondialdehyde; MDA). This enhancement was correlated by increasing the activities of antioxidant enzymes, i.e., superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (G-POX), and ascorbate peroxidase (APX). Gene expression analyses conducted using qRT-PCR demonstrated that genes coding for the Na+/H+ antiporter protein Salt Overly Sensitive 1 (SOS1), the tonoplast-localized Na+/H+ antiporter protein (NHX1), and the multifunctional osmotic protective protein (Osmotin) were significantly up-regulated in the FA-treated plants under both saline and non-saline treatments. Generally, treatment with 0.2 mM FA was more potent than 0.1 mM and can be recommended to improve snap bean tolerance to salinity stress.

Role of biochar and compost in cadmium immobilization and on the growth of Spinacia oleracea.

This research was carried out to evaluate the effect of biochar and compost application on Spinacia oleracea growth in cadmium contaminated soil. Cd toxicity decreased plant growth and biomass significantly and also negatively affected the physiological and biochemical attributes of plants. However, the application of biochar and compost improved the contaminated soil by reducing Cd toxicity and causing its immobilization, which in turn improved plant growth. The combined application of biochar and compost significantly (p < 0.05) enhanced biomass and photosynthetic pigments development in plants. The treatments also increased membrane stability index by 45.12% and enhanced water using efficiency by 218.22%, respectively. The increase in antioxidant activities was 76.03%, 29.02%, and 123.27% in superoxide dismutase, peroxidase, and catalase, respectively. The combined application also reduced the cadmium content (reduced 40.14% in root and 51.16% shoot), its translocation (19.67% decrease), and bioaccumulation (52.63% and 40.32% decrease in Cd content in shoot and root, respectively) in spinach plant. Among the two selected varieties of S. oleracea, Desi palak (V1) performed better as compared to Kanta palak (V2). It can be concluded that the combined application of biochar and compost is one of the best strategies to reduce the toxicity level of Cd in plants and to improve their growth.

Exogenous arginine treatment additively enhances growth and tolerance of Salicornia europaea seedlings under salinity

The effects of foliar application of 5 mM arginine (Arg) on the growth and control of salinity-induced osmotic and oxidative stresses (0, 200, 400 and 600 mM NaCl) in Salicornia europaea seedlings were investigated. Despite higher levels of lipid peroxidation, lower membrane stability index (MSI), decreased pigment content and phenolic compounds, and reduced activity of antioxidant enzymes observed under salinity, seedling growth indices, including plant height and biomass, increased significantly, and some protective and antioxidant molecules such as proline and flavonoids accumulated. Soluble protein level increased at the low salt concentration (200 mM) but decreased at other doses. Exogenous Arg treatment alone had less or no effect on plant biomass and other metabolites, but in combination with salt, further enhanced growth parameters, MSI and accumulation of soluble protein, phenolic compounds and proline. Arg-induced changes under salinity were associated with decreased lipid peroxidation, flavonoids content and antioxidant enzymes activity. These results show that S. europaea seedlings are well tolerant to applied salt doses. The treatment with exogenous Arg alone affects plant growth slightly, but in combination with salt, synergistically increases growth and salt tolerance of these plants by enhancing the accumulation of proline and antioxidant molecules instead of enzymatic antioxidant.

Salicylic Acid Stimulates Defense Systems in Allium hirtifolium Grown under Water Deficit Stress.

Nowadays, the use of the growth regulator salicylic acid for improving a plant’s resistance to environmental stresses such as drought is increasing. The present study investigated the effect of salicylic acid on the physiological traits, antioxidant enzymes, yield, and quality of Allium hirtifolium (shallots) under drought conditions for three years (2016–2017, 2017–2018, and 2018–2019). The experiment was conducted as a split-plot based on a randomized complete block design with four repeats. Irrigation as the main factor in four levels of 100% (full irrigation), 75% and 50% of the plant water requirements with non-irrigation (dryland), and salicylic acid as the sub-factor in four levels of 0, 0.75, and 1 mmol, were the studied factors in this research. The combined analysis of three-year data showed that drought reduced leaf relative water content (RWC), membrane stability index (MSI), chlorophyll content, onion yield, and increased activity of antioxidant enzymes, proline content, tang, and allicin of shallots. Shallot spraying with salicylic acid improved leaf RWC, MSI, chlorophyll content, and onion yield. The highest yield of onion (1427 gr m−2) belonged to full irrigation and foliar application of 1 mmol salicylic acid. The lowest yield (419.8 gr m−2) belonged to plats with non-irrigation and non-application of salicylic acid. By improving the effective physiological traits in resistance to water deficit, salicylic acid adjusted the effects of water deficit on the yield of shallots. Foliar application of 1 mmol salicylic acid in dryland and irrigation of 50% of the plant water requirement increased onion yield by 15.12% and 29.39%, respectively, compared to the control treatment without salicylic acid.

The Effects of Hydro-Priming and Colonization with Piriformospora indica and Azotobacter chroococcum on Physio-Biochemical Traits, Flavonolignans and Fatty Acids Composition of Milk Thistle (Silybum marianum) under Saline Conditions

Salinity is an important challenge around the world, effecting all physiological and biochemical processes of plants. It seems that seed priming can diminish the negative impacts of salinity. To study the effects of hydro-priming and inoculation with Piriformospora indica (Pi) and Azotobacter chroococcum (Az) on physio-biochemical traits, flavonolignans and fatty acids composition of milk thistle under saline conditions, a greenhouse experiment was carried out. Our results indicated that under salinity, seed priming, especially Pi, improved physio-biochemical properties in milk thistle. Under 120 mM NaCl, inoculation with Pi increased membrane stability index (MSI) and relative water content (RWC) (by 21.86 and 33.43%, respectively). However, peroxidase (POX) (5.57- and 5.68-fold in roots and leaves, respectively), superoxide dismutase (SOD) (4.74- and 4.44-fold in roots and leaves, respectively), catalase (CAT) (6.90- and 8.50-fold in roots and leaves, respectively) and ascorbate peroxidase (APX) (5.61- and 5.68-fold in roots and leaves, respectively) activities increased with increasing salinity. Contrary to salinity, hydro-priming with Az and Pi positively altered all these traits. The highest content of the osmolytes, adenosine triphosphate (ATP) content and rubisco activity were recorded in Pi treatments under 120 mM NaCl. Stearic acid (20.24%), oleic acid (21.06%) and palmitic acid (10.48%) increased, but oil content (3.81%), linolenic and linoleic acid content (22.21 and 15.07%, respectively) decreased under saline conditions. Inoculations of Pi positively altered all these traits. The present study indicated that seed priming with Pi under 120 mM NaCl resulted in maximum silychristin, taxidolin, silydianin, isosilybin, silybin and silymarin of milk thistle seeds.

Glyoxalase III enhances salinity tolerance through reactive oxygen species scavenging and reduced glycation.

Methylglyoxal (MG) is a metabolically generated highly cytotoxic compound that accumulates in all living organisms, from Escherichia coli to humans, under stress conditions. To detoxify MG, nature has evolved reduced glutathione (GSH)-dependent glyoxalase and NADPH-dependent aldo-keto reductase systems. But both GSH and NADPH have been reported to be limiting in plants under stress conditions, and thus detoxification might not be performed efficiently. Recently, glyoxalase III (GLY III)-like enzyme activity has been reported from various species, which can detoxify MG without any cofactor. In the present study, we have tested whether an E. coli gene, hchA, encoding a functional GLY III, could provide abiotic stress tolerance to living systems. Overexpression of this gene showed improved tolerance in E. coli and Saccharomyces cerevisiae cells against salinity, dicarbonyl, and oxidative stresses. Ectopic expression of the E. coli GLY III gene (EcGLY-III) in transgenic tobacco plants confers tolerance against salinity at both seedling and reproductive stages as indicated by their height, weight, membrane stability index, and total yield potential. Transgenic plants showed significantly increased glyoxalase and antioxidant enzyme activity that resisted the accumulation of excess MG and reactive oxygen species (ROS) during stress. Moreover, transgenic plants showed more anti-glycation activity to inhibit the formation of advanced glycation end product (AGE) that might prevent transgenic plants from stress-induced senescence. Taken together, all these observations indicate that overexpression of EcGLYIII confers salinity stress tolerance in plants and should be explored further for the generation of stress-tolerant plants.

Effect of fungal elicitors on morphophysiological characteristics and resistance to gray mold caused by Botrytis cinerea in cut flowers of rose

The present study aimed to enhance the vase life, maintain quality, and reduce the percentage of infection with gray mold caused by Botrytis cinerea using fungal elicitors on cut flowers of roses. Based on a completely randomized design with three replications, a factorial experiment was performed. The eight treatments were as follows: three concentrations of fungal elicitor (600, 800 and 1000 ppm), the three concentrations along with B. cinerea fungal spores, sterile distilled water (as negative control), and B. cinerea spore suspension (positive control). Vase life, cell membrane stability index, superoxide dismutase, catalase, carbohydrate content, and disease severity on the leaves were measured during the experiment. The measurements were carried out on days 3, 7 and 10 after spraying the spores. The results showed that treating rose flowers with the elicitor (1000 ppm) improved soluble carbohydrate preservation, cell membrane stability index, relative water content, catalase enzyme, and leaf superoxide dismutase, resulting in a significant increase in vase life (15.66 days) compared to the control (8.66 days) (P?0.01). Evaluating the disease index also showed that the elicitor (1000 ppm) along with B. cinerea spores caused a significant increase in vase life (12.33 days) compared to the positive control (7.66 days) (P?0.01). Finally, the disease severity in treated samples was lower than that of the B. cinerea treatment as control.

Melatonin Mitigates Drought Induced Oxidative Stress in Potato Plants through Modulation of Osmolytes, Sugar Metabolism, ABA Homeostasis and Antioxidant Enzymes.

The effect of melatonin (MT) on potato plants under drought stress is still unclear in the available literature. Here, we studied the effect of MT as a foliar application at 0, 0.05, 0.1, and 0.2 mM on potato plants grown under well-watered and drought stressed conditions during the most critical period of early tuberization stage. The results indicated that under drought stress conditions, exogenous MT significantly (p ≤ 0.05) improved shoot fresh weight, shoot dry weight, chlorophyll (Chl; a, b and a + b), leaf relative water content (RWC), free amino acids (FAA), non-reducing sugars, total soluble sugars, cell membrane stability index, superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (G-POX), and ascorbate peroxidase (APX) compared to the untreated plants. Meanwhile, carotenoids, proline, methylglyoxal (MG), H2O2, lipid peroxidation (malondialdehyde; MDA) and abscisic acid (ABA) were significantly decreased compared to the untreated plants. These responses may reveal the protective role of MT against drought induced carbonyl/oxidative stress and enhancing the antioxidative defense systems. Furthermore, tuber yield was differentially responded to MT treatments under well-watered and drought stressed conditions. Since, applied-MT led to an obvious decrease in tuber yield under well-watered conditions. In contrast, under drought conditions, tuber yield was substantially increased by MT-treatments up to 0.1 mM. These results may imply that under water deficiency, MT can regulate the tuberization process in potato plants by hindering ABA transport from the root to shoot system, on the one hand, and by increasing the non-reducing sugars on the other hand.

Effect of Glyphosate on Physiology and Biochemical Properties of Purple Nutsedge (Cyperus rotundus L.)

The study was conducted to understand the influence of herbicide on the changes in physiology and biochemical properties of purple nutsedge weed (Cyperus rotundus L.). Laboratory and pot culture study were conducted at the Department of Agronomy, Tamil Nadu Agricultural University, Coimbatore during 2020-21. Glyphosate was tested with different concentrations (500, 600, 700, 800, 900 and 1000 ppm) and various soaking duration (6, 12, 24 and 48 hrs) with three replication. The extent of weed damage is based on the site of herbicide action, inhibition of enzymes activity and other metabolic functions. It resulted in chlorophyll content and membrane stability index of the weeds were affected. Proline level of treated weeds were found to be increased at initial stage of herbicide application and followed by declined gradually. It causes the weeds to kill by exhibiting oxidative stress. Phytotoxic effect of herbicide application was visualized until 15-20 DAHA (days after herbicide application) and thereafter weeds were died due to cessation of all the metabolic activities. The findings of the soaking experiment confirmed the negative impact of herbicide on phenol and starch content in tubers. Phenol degradation or dilution was observed to be increased with increasing duration of soaking period and however starch content decreases simultaneously. The results showed that application of glyphosate @ 1000 ppm is more effective to arrest the population of Cyperus rotundus.

Agronomic Performance of Chickpea Affected by Drought Stress at Different Growth Stages

Susceptibility to drought stress has restrained chickpea productivity at a global level, and the development of drought-tolerant varieties is essential to maintain its productivity. Therefore, the present study was conducted to evaluate genetic divergence in selected genotypes of chickpea and their morpho-physiological responses under irrigated and stressed conditions to identify the traits that account for the better performance of these genotypes under stressed conditions, as well as genotypes with improved drought tolerance. The genotypes were evaluated for two years under irrigated and drought stressed conditions, and significant variation was found amongst the genotypes for different morpho-physiological and yield traits. The maximum reduction was observed for plant yield (33.23%) under stressed conditions. Principle component analysis (PCA)-based biplots and correlation studies established its strong positive correlation with relative water content (RWC), membrane stability index (MSI), chlorophyll index (CI), secondary branches (SB) and yield traits and negative correlations with drought susceptibility index (DSI), days to maturity (DM) and 100 seed weight (100 SW) under drought stress, suggesting their use in selecting drought-tolerant germplasm. Ten genotypes with high values of RWC, MSI, CI, SB, yield traits and lower DSI were identified as drought-tolerant and might serve as ideal donors in the forthcoming breeding of elite chickpea cultivars. The seed-filling stage began earlier in these genotypes, with significantly reduced days to maturity under stressed conditions. Our results indicate selection for earliness offers a promising strategy for the development of drought-tolerant chickpea cultivars.

Effect of Piriformospora indica-Induced Systemic Resistance and Basal Immunity Against Rhizoctonia cerealis and Fusarium graminearum in Wheat.

Wheat is among the top 10 and most widely grown crops in the world. However, wheat is often infected with many soil-borne diseases, including sharp eyespot, mainly caused by the necrotrophic fungus Rhizoctonia cerealis, and Fusarium head blight (FHB), caused by Fusarium graminearum, resulting in reduced production. Piriformospora indica is a root endophytic fungus with a wide range of host plants, which increases their growth and tolerance to biotic and abiotic stresses. In this study, the capability of P. indica to protect wheat seedlings against R. cerealis and F. graminearum was investigated at the physiological, biochemical, and molecular levels. Our results showed that P. indica significantly reduced the disease progress on wheat caused by F. graminearum and R. cerealis in vivo, but not showed any antagonistic effect on F. graminearum and R. cerealis in vitro. Additionally, P. indica can induce systemic resistance by elevating H2O2 content, antioxidase activity, relative water content (RWC), and membrane stability index (MSI) compared to the plants only inoculated with F. graminearum or R. cerealis and control. RNA-seq suggested that transcriptome changes caused by F. graminearum were more severe than those caused by R. cerealis. The number of differentially expressed genes (DEGs) in the transcriptome can be reduced by the addition of P. indica: for F. graminearum reduced by 18% and for R. cerealis reduced 58%. The DEGs related to disease resistance, such as WRKY and MAPK, were upregulated by P. indica colonization. The data further revealed that the transcriptional resistance to F. graminearum and R. cerealis mediated by P. indica is quite different.

Soaking Maize Seeds in Zeatin-Type Cytokinin Biostimulators Improves Salt Tolerance by Enhancing the Antioxidant System and Photosynthetic Efficiency.

There is an urgent need for innovative strategies to raise the performance of environmentally stressed plants. The seeds of single-cross yellow Zea mays (L.) hybrid Giza-168 were soaked in Cis-(c-Z-Ck) or trans-zeatin-type cytokinin (t-Z-Ck) solutions at a concentration of 50 or 40 µM, respectively. Salinity stress was imposed at 0, 75 or 150 mM NaCl in the Hoagland nutrient solution (full strength) used for irrigation. The total carotenoids content was negatively affected by only 150 mM NaCl, while both 75 and 150 mM NaCl negatively affected the growth and yield components, relative water content, membrane stability index, photochemical activity, gas exchange, K+ and chlorophyll contents, K+/Na+ ratio, and photosynthetic efficiency. However, all of these traits were significantly improved by c-Z-Ck pretreatment and further enhanced by t-Z-Ck pretreatment compared with the corresponding controls. Furthermore, the contents of proline, soluble sugars, ascorbate, and glutathione, as well as enzymatic antioxidant activities, were significantly elevated by both salt stress concentrations and increased more by both biostimulators compared to the control. Compared to c-Z-Ck, t-Z-Ck was superior in mitigating the harmful effects of the high H2O2 levels caused by salt stress on the levels of malondialdehyde and ion leakage compared to the control. Under normal or stress conditions, t-Z-Ck pretreatment was better than c-Z-Ck pretreatment, while both positively affected maize hormonal contents. As a result, t-Z-Ck is recommended to enhance the growth and productivity of maize plants by suppressing the effects of oxidative stress caused by saline water irrigation.