Abstract:

The 2-year-old seedlings of two litchi(Litchi chinensis Sonn.)cultivars grown in pots with different drought-resistance were used in this study.“Chenzi” grown in riverside is considered to be drought-sensitive,while “Dongliu 1” grown on hills is considered to be drought-resistant.Effects of water stress on some enzyme activities related to respiratory metabolism in litchi leaves were studied.The results showed:(1)Under water stress,the relative water content(RWC) of litchi leaves decreased,and the extent of decrease was less in drought-resistant “Dongliu 1” than in drought-sensitive “Chenzi”. (2)Under water stress,the activities of Mg²⁺-ATPase and Ca²⁺-ATPase in mitochondria of litchi leaves increased,and the activity of glycolate oxidase decreased.The extent of Mg²⁺-ATPase and Ca²⁺-ATPase activities increase and the extent of glycolate oxidase activity decrease in drought-resistant cultivar were higher than in drought-sensitive one.(3)The activities of Glucose-6-phosphate dehydrogenase(G-6-PDH) and NADH-cytochrome c reductase(NADH-CCR) in the litchi leaves decreased and the ratios of NADH-CCR activity/G-6-PDH activity increased under water stress.The extent of G-6-PDH and NADH-CCR activity decrease and the extent of NADH-CCR activity/G-6-PDH activity increase in drought-sensitive cultivar were greater than in drought-resistant one.

Key words: Litchi chinensis, Water stress, Activities of respiratory enzymes