Nitric oxide and spermine revealed positive defense interplay for the regulation of the chromium toxicity in soybean (Glycine max L.)

Current investigation demonstrated that chromium (Cr) toxicity affects adversely on the normal growth of soybean plants. However, the seed priming with nitric oxide (NO; 100 μM), and spermine (Spm; 0.01 Mm) can significantly alleviate the Cr toxicity in soybean plant. Herein, the hydroponic experiment was conducted to observe the individual as well as the interactive behavior of NO, and Spm on the various morpho-physiological and, biochemical parameters in soybean such as plant growth, plant height, seed germination indices, photosynthesis-related indices such as chlorophyll biosynthesis, PS system II, nutrient uptake of soybean seedlings against Cr (VI) toxicity. Our outcomes deliberated that the alone treatment of NO, and Spm cause a significant improvement in seed germination ratio, photosynthetic pigments, and biomass of plants by restricting Cr uptake; while NO + Spm treatment being more effective in the improvement of soybean growth relative to their individual treatment under Cr stress. Relative to alone treatment of NO, and Spm, the combined treatment significantly modulated the antioxidant activities, and lowered the ROS accumulation, and electrolyte leakage. In addition, seed priming with NO, and Spm mitigate the Cr-induced toxicity by reducing Cr uptake and stimulating the antioxidative defense mechanisms. Hence, these findings confirmed the positive defense interplay of the NO and Spm in the modulation of the Cr tolerance in soybean. However, the underlying defense mechanism of these synergetic effects needs to be further explored.