Lipoperoxidation in Grain Sorghum under the Influence of Herbicides, Phytohormones, and Biopreparation

Abstract

The use of herbicides for sowing grain cultures, including grain sorghum, is an integral condition for high yield indicators. However, upon penetrating into plant organisms, herbicides can intensify synthesis of the reactive oxygen species, which leads to the aggravation of lipid peroxidation and activates antioxidant systems, namely superoxide dismutase enzyme. It is known that phytohormones and microbial preparations, if included in the cultivation technology, can improve plants’ ability to resist oxidative stress caused by xenobiotics. However, the integrative influence of herbicides, phytohormones, and microbial preparations on activity of superoxide dismutase enzyme as well as on lipid peroxidation intensity in plants of grain sorghum is understudied, which preconditioned the purpose of this study. The objects of this study were as follows: grain sorghum (Sorghum bicolour (L.) Moench) of the Milo W hybrid, herbicide Cytadel 25 OD, phytohormone Endofit L1 and biopreparation Bioarsenal. The study was conducted following the requirements of vegetation method. The activity of lipid peroxidation was investigated according to the number of malondialdehyde formed in the plant tissues. The activity of superoxide dismutase enzyme (EC 1.15.1.1) was investigated according to its ability to compete with nitro blue tetrazolium for superoxide anions resulting from interaction between the reduced form of nicotinamide adenine dinucleotide phosphate and phenazine methosulfate. The study revealed that under the effect of the herbicide Cytadel 25 OD, indicators of the lipid peroxidation activity in plants averaged 26.2-93.2% higher than in control sample, depending on the herbicide rate and the day after application. Activity of superoxide dismutase in these conditions exceeded that in the control sample by 18.2-96.8% on average. However, provided the joint use of herbicides, phytohormones, and biopreparation, the plants demonstrated a decrease of the lipid peroxidation activity. It lowered by 14.5-19.1% against the background of superoxide dismutase increase by 22.0-38.7% relatively to the variants where only herbicide was used. Results of the experiment attest the positive influence of the phytohormone and biopreparation on the grain sorghum’s resistance to the oxidative stress caused by herbicides. The observed data can become a cornerstone for the further development of biologised cultivation technologies of this culture