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Glandless cotton can be grown to obtain cotton seeds free of toxic gossypol for use as both food and feed. However, they are not grown normally due to their lesser productivity and higher susceptibility to biotic stress. Great attention has been paid to biotic stresses rather than abiotic stresses on glandless cotton. Chromium (Cr) is a common pollutant of soil and considered a serious threat to plants due to its adverse effects on different functions. Although numerous studies are available on the toxicity of Cr6+ in various plants. However, its adverse effects and mechanism of toxicity in glandless cotton can seldom be found in the literature. This study examined the Cr6+ effect on glandless cotton in comparison to glanded cotton. Four pairs of glanded and glandless cotton near-isogenic lines (NILs) were exposed to different doses (0, 10, 50, and 100 μM/L) of Cr6+ for seven days, and biochemical, physiological, molecular, and ultrastructure changes were observed, which were significantly affected by Cr6+ at high concentrations in all NILs. The effect of Cr6+ on ionic contents shows the same trend in glanded and glandless NILs except for manganese (Mn2+) that show inhibition in glandless (ZMS-12w and Coker-312w) and enhance in the glanded NIL (ZMS-17). The gene expression of superoxide dismutase (SOD) and peroxidase (POD) revealed similar trends as enzyme activities in glandless NILs. The principal component analysis (PCA) and Agglomerative hierarchical clustering (AHC) results of all NILs from morpho-physiological traits, cluster ZMS-16, and ZMS-17 into Cr6+ sensitive group. While the glandless NILs have the potential to cope with the Cr toxicity by increasing the antioxidant enzyme activity and their gene expression. This study also revealed that Cr6+ tolerance in cotton is genotypic and has an independent mechanism in the root that not related to low gossypol. Image 1 • Chromium (Cr) adversely affects plant growth and root morphology. • Cr impaired nutrients uptake and enhance H 2 O 2 that leads to ultrastructure damages. • Cr-induced phytotoxicity varied among cotton near-isogenic lines (NILs). • Glandless cotton shows more resistance to Cr stress as compared to glanded cotton. [ABSTRACT FROM AUTHOR]

Pesticides are usually used to eliminate weeds and insects to improve crop quality and yield. The present study was undertaken to explore pesticides (Lambda cyhalotherin (LC) and Emamectin benzoate (EB)) related physiological, biochemical and ultrastructural changes in leaves of maize seedlings at different concentrations of LC and EB both singly (LC100, LC500, LC800, EB100, EB300, EB600 mg/L) and jointly (LC500 + EB300 mg/L) along with control. Germination percentage, root stem and leaf lengths increased at lower concentrations of both pesticides and significantly decreased with the increase in the external application of pesticides. At higher concentrations of LC and EB (i.e., LC800 and EB600 mg/L) the mean values of growth and biomass of maize leaves were lower than control. Also, decreases in photosynthetic pigments and ion concentration of Na1+, Ca2+ and K1+ were significant when the concentration of both pesticides increased. The melondialdehyde (MDA) contents decreased, while the amount of hydrogen peroxide (H2O2) production increased at higher doses in cases of single and joint applications. With the increase in their concentrations, the activities of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were found to be pronouncedly enhanced as compared to control. Ultrastructural alterations in mesophyll cells of maize leaf were mostly found in chloroplast and nucleus. The present study revealed that short-term exposure of maize seedlings to pesticides (LC and EB) caused less stressful effects on maize due to the presence of active antioxidative metabolism, which indicates the resistant nature of maize toward these pesticides. [ABSTRACT FROM AUTHOR]