Abstract:

This paper studied the response of growth, reactive oxygen species metabolism and antioxidative enzyme activities of two different pak-choi cultivars ('Aiwang'and 'Lvyou') to low light under shading treatment and regular light recovery. The results showed that the growth of 'Aiwang' was retarded and the growth of 'Lvyou' was complete inhibited under shading treatment. The MDA content, the O₂-. Production rate and the H₂O₂ content in two cultivars decreased at first and increased later. The POD activities increased under shading treatment while the SOD, CAT and APX decreased firstly and increased later. The activities of all theses enzymes increased remarkably after the recovery of growth light. The results suggested that, under shading treatment and regular light recovery, 'Aiwang' was more efficient on the enhancement of antioxidative enzymes activities to reduce the membrane lipid peroxidation, while 'Lvyou' was subject to a more grave membrane lipid peroxidation.

Key words: Pak-choi, Shading, Growth, Reactive oxygen metabolism, Antioxidant enzymes