关键词: 小麦-蚕豆间作, 根系分泌物, 有机酸数量, 有机酸种类, 分泌速率

Abstract: Schima superba, an important tree species of China subtropical evergreen broadleaf forests, suffered from the ice and snow disaster in 2008. In this study, five 400 m² plots were randomly established in Jianglangshan Mountain of Zhejiang Province, and the damaged S. superba trees were classified into decapitated and uprooted. The photosynthetic responses, gas-exchange, and chlorophyll fluorescence parameters of the sprouts at different segments were studied, aimed to understand the mechanisms of the community regeneration after the extreme disturbance and to provide a theoretical basis for the study of sprout ecology in subtropical regions. As for the different age-class leaves, 2-year-old leaves had the higher maximum net photosynthetic rate (P_max), maximal photochemical efficiency of PSⅡ (F_v/F_m), potential activity of PSⅡ (F_v/F₀), effective photochemical efficiency of PSⅡ (F_v′/F_m′), leaf mass per area (LMA), and nitrogen (N) content than 1-year-old leaves. 2-year-old leaves also had a significantly higher chlorophyll (a+b) content than 1-year-old leaves (p<0.05), but the chlorophyll a/b ratio was lower than that of 1-year-old leaves. For the sprouts at different segments, the sprouts at the middle segment of decapitated trees and at the basal segment of uprooted trees had the highest F_v/F_m, F_v/F₀, F_v′/F_m′, Chl(a+b), Chla/b, and carotenoids (Car). The sprouts at the top segment of decapitated trees had the highest LMA and N content, followed by those at middle segment, and at basal segment. For uprooted trees, the LMA and N content exhibited an opposite order, i.e., basal segment > middle segment > top segment, and the net photosynthetic rate (P_n) and water use efficiency (WUE) were significantly higher than those of decapitated trees (P<0.05). Decapitated trees had broader ecological amplitude to sunlight, with lower light compensation point (LCP) and higher light saturation point (LSP) than uprooted trees.

Key words: wheat and faba bean intercropping, root exudates, amounts of organic acids, types of organic acids, exudation rate.