Influence of brassinosteroid and silicon on growth, antioxidant enzymes, and metal uptake of leafy vegetables under wastewater irrigation.

Vegetable cultivation under sewage irrigation is a common practice mostly in developing countries due to a lack of freshwater. Long-term usage provokes heavy metals accumulation in soil and ultimately hinders the growth and physiology of crop plants and deteriorates the quality of food. A study was performed to investigate the role of brassinosteroid (BRs) and silicon (Si) on lettuce, spinach, and cabbage under lead (Pb) and cadmium (Cd) contaminated sewage water. The experiment comprises three treatments (control, BRs, and Si) applied under a completely randomized design (CRD) in a growth chamber. BRs and Si application resulted in the highest increase of growth, physiology, and antioxidant enzyme activities when applied under canal water followed by distilled water and sewage water. However, BRs and Si increased the above-determined attributes under the sewage water by reducing the Pb and Cd uptake as compared to the control. It's concluded that sewerage water adversely affected the growth and development of vegetables by increasing Pb and Cd, and foliar spray of Si and BRs could have great potential to mitigate the adverse effects of heavy metals and improve the growth. The long-term alleviating effect of BRs and Si will be evaluated in the field conditions at different ecological zones.

Plant growth-promoting bacterial consortia improved the physiology and growth of maize by regulating osmolytes and antioxidants balance under salt-affected field conditions.

This study was undertaken to see how microbial consortia influenced maize development and yield under salt-affected conditions. The efficacy of the pre-isolated bacterial strains Burkholderia phytofirmans, Bacillussubtilis, Enterobacter aerogenes, and Pseudomonas syringae and Pseudomonas fluorescens to decrease the detrimental effects of salt on maize was tested in four distinct combinations using Randomized Complete Block Design with three replicates. The results revealed that these strains were compatible and collaborated synergistically, with an 80% co-aggregation percentage under salt-affected conditions. Following that, these strains were tested for their ability to increase maize growth and yield under salt-affected field conditions. The photosynthetic rate (11-50%), relative water content (10-34%), and grain yield (13-21%) of maize were all increased by these various combinations. However, when Burkholderia phytofirmans, Enterobacter aerogenes and Pseudomonas fluorescens were combined, the greatest increase was seen above the un-inoculated control. Furthermore, as compared to the un-inoculated control, the same combination resulted in a 1.5-fold increase in catalase and a 2.0-fold increase in ascorbate concentration. These findings showed that a multi-strain consortium might boost maize's total yield response as a result of better growth under salt stress.

Interactive effect of different salinity sources and their formulations on plant growth, ionic homeostasis and seed quality of maize.

Soil salinity is one of the most pernicious environmental hazards affecting crop growth and productivity in arid and semi-arid climates. In saline soils, the crop plants encounter nutrients deficient conditions mainly due to antagonistic affinity of sodium (Na+) and chloride (Cl-). The accumulation of salts in the rhizosphere restricts plant growth, the severity of which depends on the source and concentration of the salt. Therefore, we hypothesized that sodium containing salts could have toxic effects on maize plants either in a single or in combined form. To evaluate the interactive effect of sodium salts on plant growth, ionic homeostasis, and seed quality attributes, a pot study was performed using maize as a test plant at the research area of the College of Agriculture, University of Sargodha. Selected salts including, NaCl, Na2SO4 and their combination (NaCl + Na2SO4), were applied in equal ratio for different salinity levels (7, 10, 13 and 16 dS m-1) and the untreated control. The results show that all the measured growth, yield, biochemical and quality attributes of maize were negatively affected with increasing concentration of all the salt sources; however, severity of these effects were more intense when NaCl was applied at all salinity levels. It is concluded that all salts (NaCl, Na2SO4 and NaCl + Na2SO4) had negative effects on biochemical, qualitative, growth and yield characteristics of maize plant. Most importantly, NaCl was found to be more harmful compared to Na2SO4 and mixtures of both salts due to the dominance of Na+ and Cl-ions. Among all salinity levels, the more detrimental effects of NaCl occurred at salinity level of 16 dS m-1.