Effects of exogenous ABA on the physiological characteristics and chlorophyll fluorescence of Gynura cusimbua seedlings under drought stress

Abstract

Abstract This paper is to investigate the physiological mechanism of exogenous abscisic acid (ABA) on alleviating drought stress in Gynura cusimbua The effects of exogenous ABA on physiological characteristics and chlorophyll fluorescence parameters of the leaves of Gynura cusimbua under drought stress were studied with 10% polyethylene glycol 6000 (PEG 6000) in simulated drought stress. The results showed that the activities of antioxidant enzymes and some fluorescence parameters increased slightly after spraying exogenous ABA. Under drought stress, exogenous ABA can increase chlorophyll content, enhance antioxidant enzyme activity, reduce MDA content, increase maximum photochemical efficiency Fv / FM, regulatory energy dissipation Y (NPQ), photochemical quenching QL, actual quantum efficiency Y (II), non-photochemical quenching NPQ fluorescence parameters, and reduce non-regulatory energy dissipation Y (NO) and minimum fluorescence Fo parameters, so as to reduce the damage to seedlings under drought stress. Among them, the ABA concentration of 200 μmol/L was the best to alleviate 10% drought stress.