外源5-氨基乙酰丙酸(ALA)对弱光下黄瓜生长指标及抗氧化酶活性的影响

The experiment conducted with spraying 5-aminolevulinic acid (ALA) to cucumber (Cucumis sativus L.) seedlings of 3 varieties ('h02', 'h082' and 'Chuanlv No.1') in 2 true leaves stage, then with shading treatment. The study set 5 concentrations. They were 0 mg•L^(-1) (CK), 0.01 mg•L^(-1), 0.1 mg•L^(-1), 1 mg•L^(-1), 10 mg•L^(-1), 50 mg•L^(-1), respectively. After ALA spraying for 0 day, 2 days, 6 days, 10 days, 14 days on cucumber seedlings, leaf protect enzymes and MDA content were determined, and the growth situation of cucumber seedlings were recorded. Results showed that the application of low concentration of shading when ALA processing cucumber seedlings, can promote plant height, increase leaf area and stem diameter, improve SOD and POD activities and reduce the MDA accumulation. When ALA reaches a certain concentration, its promoting function is the strongest. Then with the concentration increases, its promotion effect weakens. This indicates that ALA can improve cucumber seedlings tolerance to weak light, and 1 mg•L^(-1) ALA treatment has the best effect.