Effects of hydrogel polymer on grain yield, some physiological characteristics, and antioxidant enzyme activity of maize in response to drought stress

Objective: Drought stress has destructive effects on the growth and performance of crops. The application of superabsorbent polymer can provide water and some nutrients to crops during the growth period. This experiment aimed to evaluate the effect of hydrogel polymer and drought stress on the characteristics of maize (variety MV ۵۲۴ Maxima).Methods: The experiment was conducted as a split-plot design based on a randomized complete block design with three replications. The drought stress levels, ۶۰ mm (control), ۱۲۰ mm, and ۱۸۰ mm, based on evaporation from the evaporation pan, were assigned to the main plots. The levels of hydrogel polymer, ۰ (control), ۷۵, ۱۵۰, and ۲۲۵ kg/ha were arranged in subplots.  Hydrogels were mixed and applied at a depth of ۲۰-۳۰ cm in the soil. Samples were taken from young leaves at the seed-filling stage to measure photosynthetic pigments and antioxidant enzymes activity. Also, at maturity, mineral elements (nitrogen, phosphorus, and potassium) in the grains, biomass, grain yield, and yield components, including ۱۰۰۰-kernel weight, number of kernels per row, number of kernel rows per ear, and plant height were measured.Results: Drought stress reduced photosynthetic pigments (chlorophyll “a”, chlorophyll “b” and carotenoids), N, P, and K content in the grains, the number of kernels per row, number of kernel rows per ear, and ۱۰۰۰-kernel weight. Also, drought stress increased the activities of catalase (CAT) and glutathione peroxidase (GPX). The application of hydrogel polymer had a positive effect on maize plants and at all drought levels, the highest grain yield, biomass, and number of kernels per row were obtained with the highest amount of hydrogel polymer (۲۲۵ kg/ha). However, hydrogel polymer decreased CAT activity and anthocyanin content, but it did not change the number of kernel rows, ۱۰۰۰-kernel weight, ion content in the grains, GPX activity, chlorophyll “a” and “b”, and carotenoids in the maize leaves.Conclusion: The results indicated that the application of ۲۲۵ kg/ha hydrogel polymer had a beneficial effect on maize and mitigated the harmful effects of drought stress.

کلیدواژه ها:

Ion content ، Maize ، Photosynthetic pigments ، Superabsorbent polymer ، Water Deficit