关键词: 修枝, 树干液流, 蒸腾速率, 叶水势

Abstract:

With poplar clone (Populus×euramericana cv. '74/76’) as the research object, this paper investigated the variation of stem sap flow, transpiration rate(T_r) and leaf water potential(LWP) during the growing season(June to September). The experiment set two experimental sites:one was 4-year-old poplar clone, and the other was 6-year-old. There were 3 treatment levels in each site: the CK(unpruned), Pl(1/3 crown was pruned) and P2(2/3 crown was pruned).The results showed: 1) The flux and velocity were P1>CK>P2 during dry season(June to August).But, in wet season of September, the flux and velocity were CK>P1>P2.The Flux and velocity of P1 were almost same between drought or wet months, which indicated that the stem sap flow of poplar was maintained at a certain low level by proper pruning and the capability of counteracting drought observably was increased after the pruning. 2) The order of transpiration rate(T_r) and leaf water potential(LWP) was CK<P1<P2, which suggested that the physiological capability of individual leaf in maintaining water balance was observably improved by pruning.

Key words: pruning, stem sap flow, transpiration rate, leaf water potential