Cotton is a highly sensitive crop to drought stress. Consequently, it is crucial to devise strategies that optimize crop production in conditions of limited water availability. While potassium silicate has demonstrated effectiveness in mitigating drought stress in various crops, its specific impact on different cotton cultivars under drought conditions remains not fully clarified. This research aimed to assess the efficacy of six potassium silicate levels (0, 100, 200, 300, 400 and 500 mg L-1) on four cotton genotypes (Zong main-113, Xin Nong-525, Xin lu Zhong-55, and Xin lu Zhong-66) under two field capacity levels (80% and 50% FC) in a sand culture. Foliar applied potassium silicate significantly improved photosynthetic efficiency, shoot biomass, root biomass, and leaf area under water stress (50% FC). The most substantial reduction in H2O2, malondialdehyde levels, and electrolyte leakage was recorded with potassium silicate applied at a rate of 400 mg L-1. This concentration effectively mitigated reactive oxygen species accumulation, safeguarding plants against oxidative damage at 50% FC. Furthermore, potassium silicate contributed to maintaining water status, resulting in increased leaf water content and elevated water-soluble proteins in cotton plants. The order of drought resistance (50% FC) with the application of potassium silicate at 400 mg L-1 was Zong Mian-113, Xin Nong-525, Xin lu Zhong-55, and Xin lu Zhong-66. The findings could help in selection of drought resistance cultivars of cotton in water limited conditions.

Lead (Pb) is a hazardous heavy metal that accumulates in many environments. Phytoremediation of Pb polluted soil is an environmentally friendly method, and a better understanding of mycorrhizal symbiosis under Pb stress can promote its efficiency and application. This study aims to evaluate the impact of two ectomycorrhizal fungi (Suillus grevillei and Suillus luteus) on the performance of Pinus tabulaeformis under Pb stress, and the biomineralization of metallic Pb in vitro. A pot experiment using substrate with 0 and 1,000 mg/kg Pb2+ was conducted to evaluate the growth, photosynthetic pigments, oxidative damage, and Pb accumulation of P. tabulaeformis with or without ectomycorrhizal fungi. In vitro co-cultivation of ectomycorrhizal fungi and Pb shots was used to evaluate Pb biomineralization. The results showed that colonization by the two ectomycorrhizal fungi promoted plant growth, increased the content of photosynthetic pigments, reduced oxidative damage, and caused massive accumulation of Pb in plant roots. The structural characteristics of the Pb secondary minerals formed in the presence of fungi demonstrated significant differences from the minerals formed in the control plates and these minerals were identified as pyromorphite (Pb-5(PO4)(3)Cl). Ectomycorrhizal fungi promoted the performance of P. tabulaeformis under Pb stress and suggested a potential role of mycorrhizal symbiosis in Pb phytoremediation. This observation also represents the first discovery of such Pb biomineralization induced by ectomycorrhizal fungi. Ectomycorrhizal fungi induced Pb biomineralization is also relevant to the phytostabilization and new approaches in the bioremediation of polluted environments.

Pea (Pisum sativum L.), a globally cultivated leguminous crop valued for its nutritional and economic significance, faces a critical challenge of soil salinity, which significantly hampers crop growth and production worldwide. A pot experiment was carried out in the Botanical Garden, The Islamia University of Bahawalpur to alleviate the negative impacts of sodium chloride (NaCl) on pea through foliar application of ascorbic acid (AsA). Two pea varieties Meteor (V1) and Sarsabz (V2) were tested against salinity, i.e. 0 mM NaCl (Control) and 100 mM NaCl. Three levels of ascorbic acid 0 (Control), 5 and 10 mM were applied through foliar spray. The experimental design was completely randomized (CRD) with three replicates. Salt stress resulted in the suppression of growth, photosynthetic activity, and yield attributes in pea plants. However, the application of AsA treatments effectively alleviated these inhibitory effects. Under stress conditions, the application of AsA treatment led to a substantial increase in chlorophyll a (41.1%), chl. b (56.1%), total chl. contents (44.6%) and carotenoids (58.4%). Under salt stress, there was an increase in Na+ accumulation, lipid peroxidation, and the generation of reactive oxygen species (ROS). However, the application of AsA increased the contents of proline (26.9%), endogenous AsA (23.1%), total soluble sugars (17.1%), total phenolics (29.7%), and enzymatic antioxidants i.e. SOD (22.3%), POD (34.1%) and CAT (39%) in both varieties under stress. Salinity reduced the yield attributes while foliarly applied AsA increased the pod length (38.7%), number of pods per plant (40%) and 100 seed weight (45.2%). To sum up, the application of AsA alleviated salt-induced damage in pea plants by enhancing photosynthetic pigments, both enzymatic and non-enzymatic activities, maintaining ion homeostasis, and reducing excessive ROS accumulation through the limitation of lipid peroxidation. Overall, V2 (Sarsabz) performed better as compared to the V1 (Meteor).

Background: Arsenic (As) is a highly toxic and carcinogenic pollutant commonly found in soil and water, posing significant risks to human health and plant growth. Objective: The objectives of this study to evaluate morphological, biochemical, and physiological markers, as well as ion homeostasis, to alleviate the toxic effects of As in sunflowers through the exogenous application of salicylic acid (SA), gamma-aminobutyric acid (GABA), and their combination. Methods: A pot experiment was conducted using two sunflower genotypes, FH-779 and FH-773, subjected to As stress (60 mg kg(-1)) to evaluate the effects of SA at 100 mg L-1, GABA at 200 mg L-1, and their combination on growth and related physiological and biochemical attributes under As stress. Results: The study revealed that As toxicity had a detrimental effect on various growth parameters, chlorophyll pigments, relative water content, total proteins, and nutrient uptake in sunflower plants. It also led to increased oxidative stress, as indicated by higher levels of malondialdehyde (MDA) and hydrogen peroxide (H2O2), along with As accumulation in the roots and leaves. However, the application of SA and GABA protected against As-induced damage by enhancing the enzymatic antioxidant defense system. This was achieved through the activation of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) activities, as well as an increase in osmolytes. They also improved nutrient acquisition and plant growth under As toxicity. Conclusions: We investigated the regulatory roles of SA and GABA in mitigating arsenic-induced phytotoxic effects on sunflower. Our results revealed a significant interaction between SA and GABA in regulating growth, photosynthesis, metabolites, antioxidant defense systems, and nutrient uptake in sunflower under As stress. These findings provide valuable insights into plant defense mechanisms and strategies to enhance stress tolerance in contaminated environments. In the future, SA and GABA could be valuable tools for managing stress in other important crops facing abiotic stress conditions.

Purpose Fly ash (FA) is a waste byproduct produced in large quantities by coal-fired power stations. Its accumulation causes environmental issues, so it needs safe disposal of FA to reduce its accumulation. Herbal medicines like Mentha arvensis are being investigated worldwide for the prevention and treatment of a wide range of disorders because of their remarkable therapeutic benefits and absence of side effects when compared to current medications. Methods The aim of the study was to determine the effect of different concentrations of fly ash on growth, biochemical parameters, and constituents of essential oils of M. arvensis. Results The findings demonstrated that FA improved some important physical and chemical properties of soil. The use of FA-amended soil (10%) significantly improved the growth performance, photosynthetic pigments, protein, proline, antioxidant activity, and mineral contents. Conversely, the higher fly ash doses (25%) resulted in oxidative stress by increasing lipid peroxidation and electrolytic leakage levels, which negatively affected all of the aforementioned parameters. A confocal microscopic examination of the roots of M. arvensis revealed that fly ash at concentration of 25% resulted in membrane damage. In addition, alcohols, phenols, allenes, ketenes, isocynates, and hydrocarbons were among the functional groups found in the control and 10% of fly ash. Gas chromatography-mass spectrometry analysis of essential oils of M. arvensis treated with 10% fly ash revealed the presence of 32 bioactive components. Conclusions It is possible to use the 10% FA concentrations to increase plant growth and decrease the accumulation of FA that pollutes the environment.