Application of abscisic acid regulates antioxidant enzymes activities and modulates endosperm cell division in winter wheat

Abstract

Effects of exogenous abscisic acid (ABA) on antioxidant enzymes activities and endosperm cell division of two wheat (Triticum aestivum L.) cultivars were investigated. Results showed that the superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activity in flag leaves of both cultivars is elevated by application of ABA and it is correlated with less membrane damage: lower malondialdehyde (MDA). Exogenous ABA significantly increased endosperm cell number and endosperm division rate, finally increased grain weight. Although ABA treatment decreased endogenous zeatin riboside (ZR) content in flag leaves from 7 to 28 days after anthesis (DAA), indole acetic acid (IAA) levels were significantly increased by spraying with ABA. Correlation analysis showed that endogenous contents of ZR, ABA, and IAA in grains were positively and significantly correlated with grain-filling rate. IAA content in leaves was positively and significantly correlated with grain-filling rate. The results suggested that increased grain weight of ABA-treated plants was due to higher antioxidant abilities of flag leaf resulting in longer maintenance of photosynthetic capacity and higher grain-filling rate.