Abiotic stresses are important constraints limiting crop productivity worldwide. Salinity is one of the most devastating environmental factors restraining the production of crops. It is urgently needed to search for environmentally safe and sustainable approaches to mitigate the harmful effects of salinity on plants. Hence, applying vermicompost and low-dose aqueous extract of sorghum delivers a pragmatic solution to ameliorate the detrimental outcomes of salinity on maize seedlings (Zea mays L.). The experiment consisted of three factors, each at different levels, i.e., salinity (control, 6, and 12 dS m⁻¹), vermicompost (control, 5, and 10%), and sorghum water extract (control, 1, and 2%). Higher salt stress negatively influenced the morpho-physiological traits of maize. Nonetheless, applying vermicompost and sorghum water extract at 10% and 2%, respectively, increased tolerance against salinity. The application of 2% sorghum water extract and 10% vermicompost significantly improved morphological characteristics, chlorophyll contents, activities of antioxidant enzymes, leaf and root K⁺/Na⁺ ratio, and K⁺ contents. It decreased Na+ concentration, H₂O₂, and malondialdehyde contents at higher salinity levels. It can be concluded that soil-applied vermicompost and foliar-applied sorghum water extract mitigates the adverse impacts of salinity by activating the antioxidant defense system, improving chlorophyll contents, and reducing the accumulation of Na⁺ under salinity.

Drought is a major environmental constraint, affecting agricultural productivity worldwide. Allelopathic hormesis, the low-dose stimulatory effect of allelochemicals, offers a pragmatic solution in alleviating the adverse effects of drought in plants. This study, therefore, is conducted to evaluate the potential of a brassica water extract (BWE) in enhancing drought tolerance in wheat. The experiment was based on three factors, viz, drought with three levels (100%, 60% and 30% field capacity; FC), different concentrations of a brassica water extract (control, water spray, 0.5%, 1.0%, 1.5%, 2.0%, 2.5% and 3.0%) and two wheat cultivars, Ihsan-2016 (drought tolerant) and Galaxy-2013 (drought-sensitive). Drought stress, particularly at 30% FC, decreased the morpho-physiological attributes of both wheat cultivars; nevertheless, the application of brassica water extract, particularly at 2.0%, effectively enhanced tolerance against drought stress. Compared with the control, the application of 2.0% brassica water extract increased the morphological attributes, such as seedling length and the fresh and dry weights of both wheat cultivars in the range of 2–160% under 30% field capacity. In addition, the 2.0% brassica water extract triggered the activities of antioxidant enzymes, including superoxide dismutase, catalase and peroxidase (11–159%), decreased the hydrogen peroxide content (14–30%) and enhanced chlorophyll a and b and carotenoid contents (19–154%), as compared to the control, in both wheat cultivars under 30% field capacity. The vigorous growth and higher drought tolerance in wheat cultivars with brassica water extract application were related to improved chlorophyll contents and physiological attributes, a better antioxidant defense system and a reduced H₂O₂-based damaging effect.

Lead (Pb) is the most common heavy metal contaminant in the environment, and its concentration is continuously increasing owing to anthropogenic activities. Phytoremediation is a green technique used globally to remediate polluted soils. The role of weeds as potential phytoremediation agents has rarely been reported in the literature. Weeds are more tolerant to abiotic stress; hence, it was hypothesized that these can serve the purpose more efficiently. Therefore, a pot experiment was conducted to evaluate the phytoremediation potential of five winter weeds, namely Avena fatua, Phalaris minor, Coronopus didymus, Chenopodium murale, and against various levels of Pb stress: control, 100 and 200 ppm. Results depicted that all the weeds could survive under higher levels of Pb; nonetheless, exposure to 200 ppm Pb stress reduced shoot dry weight (29%-69%) across all weeds. The internal CO2 concentration, photosynthesis rate, stomatal conductance, and transpiration rate decreased (5-60%) among all weeds with increasing Pb stress levels. However, Avena fatua, Phalaris minor, and Chenopodium murale depicted better gas exchange attributes than other weeds. Moreover, increased (4-60%) antioxidant activity was observed in all weeds at 100 ppm Pb level; nevertheless, it decreased at 200 ppm Pb. Additionally, Pb concentration was highest in Avena fatua, Phalaris minor, and Coronopus didymus (60-75 ppm), and the bio-accumulation factor showed that Avena fatua and Coronopus didymus were the accumulators of Pb. The translocation factor of Phalaris minor was more than 1, depicting that Pb was translocated more into shoots from roots; all other weeds accumulated more Pb in their roots than shoots. Thus, it can be concluded that different winter weeds can thrive under Pb stress, and Avena fatua and Coronopus didymus can serve the purpose of phytoremediation.