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

以黄瓜品种h02、h082、川绿1号为试材，幼苗二叶一心期时进行遮光，然后叶片表面喷施5-氨基乙酰丙酸（ALA）0（CK）、0.01、0.1、1、10、50 mg?L-1等 5个浓度。ALA喷施后0、2、6、10、14 d对黄瓜幼苗叶片的抗氧化酶活性、丙二醛含量进行测定，并记录黄瓜幼苗的生长情况。结果显示：遮光时施用低浓度的ALA处理黄瓜幼苗，可促进株高、叶面积等的生长，增加茎粗，提高SOD和POD的活性，减少MDA的积累，当ALA达到一定浓度时促进作用最强，而后随着浓度的增加，促进作用减弱。说明ALA可以提高黄瓜幼苗对弱光的耐性，且以1 mg?L-1的ALA处理效果最佳。

Effect of Exogenous ALA on Cucumber Growth Indices and Antioxidant Enzymes Activity under Suboptimal Light

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.