Interactive effect of boric acid and temperature stress on phenological characteristics and antioxidant system in Helianthus annuus L

Abstract

Plants have to cope with more than one abiotic stress at the same time in nature. Heat stress and mineral toxicity are at the forefront of these abiotic stresses. The purpose of this study is to investigate the interactive effects of high and low-temperature stress and boric acid application on the sunflower and reveal the potential protection mechanisms against the combined effect of two types of stress. Two different boric acid concentrations (10 and 25 mM) were applied to sunflowers grown separately at low (15 degrees C), optimum (25 degrees C) and high (40 degrees C) temperature. Then, root length and stem height, root and stem fresh-dry weight, root and stem biomass, malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) enzyme activities and changes in the gene expression levels of these enzymes were determined. It was determined that there were reductions in the phenological properties of the roots and stems of the samples grown at 40 degrees C based on the increasing boric acid concentration, while the samples grown at 15 degrees C were positively affected. The antioxidant enzyme activities and mRNA levels of the root and leaf samples at 40 degrees C were observed to increase. For the samples at 15 degrees C, the antioxidant enzyme activities and mRNA levels increased in the roots and decreased in the leaves. Considering phenological parameters, it was revealed that high boric acid application at low temperatures promoted plant growth, and considering the antioxidant enzyme activities and mRNA expression levels, it was highly effective in the plant's toleration of low temperatures. (C) 2022 SAAB. Published by Elsevier B.V. All rights reserved.