Mitigative effect of 5-aminolevulinic acid in pepper under low temperature stress.

Effect of 5-aminolevulinic acid(ALA 25 mg·L-1) on the growth,Pro,soluble sugar and soluble protein contents,the activities of superoxide dismutase(SOD),peroxidase(POD),catalase(CAT),ascorbate peroxidase(APX) and electrolyte leakage(EL),MDA contents of leaves was conducted with pepper variety 'Chaoyue No.5' in flowering stage under low temperature stress and the subsequent recovery process.Preliminarily explore the physiological mechanisms of ALA on improving the chilling resistance of pepper.Results showed that 25 mg·L-1 ALA significantly increased the growth mass,Pro,soluble sugar and soluble protein contents and the activities of POD,CAT and APX,significantly decreased the EL and MDA content and the activities of SOD under the low temperature stress,while the content of osmotic adjustment,MDA and the activities of POD,CAT,APX decreased under the normal conditions.It indicates that exogenous ALA treatment could improve the growth and relieve chilling injury of pepper by increasing the content of osmotica and the activities of antioxidant enzymes.