摘要：
The short effects of pruning intensities on the growth and physiologydynamics for triploid clones Populus tomentosa plantation were evaluated at Weixian County,north of China.The DBH(diameter out of bark at breast height),tree height,tree volume increment index,Pn(leaf net photosynthetic rate),Vsp(sap flow velocity) were used to evaluated the effects of pruning on 8-years-old triploid clones P tomentosa at the second year after pruning.The result showed that,at the second year after pruning,the DBH increment of the slight pruning intensity (all branches were pruned under 5 m) was greater than the CK(unpruned trees) ones(P=0.034) in the whole growth season,and the DBH increment of slight pruning intensity was greater than the severe pruning intensity(all branches were pruned under 7m) and the CK ones significantly(P=0.024)between the mid May to mid June,and the DBH increment were 1.59 and 1.69 times of severe and CK ones respectively.Tree volume increment index was increased significantly after slight pruning intensity (P=0.008),whose value was 140.66 and 90.16 percent higher than that CK and severe ones respectively.Leaf Pn of slight pruning and CK was 9.43 percent higher than that severe one,but it was different significantly among the treatments at some special time such as 10:00 of May 16.The Vsp was not affected by pruning,and the Vsp of CK was 3.36 percent higher than that slight and severe ones respectively.In conclusion,tree growth and water use efficiency of triploid clones P.tomentosa plantation could be improved by pruning,and the slight pruning intensity was the best.%以8年生三倍体毛白杨优良无性系B301速生人工林为对象,从胸径、树高、材积生长、叶片净光合速率、树干边材液流等生长、生理角度,探讨修枝对三倍体毛白杨的短期影响.结果表明,修枝第二年,消除初始条件影响后,轻度修枝三倍体毛白杨胸径年生长量显著大于对照(P=0.034);5月中旬到6月中旬,轻度修枝胸径生长量显著大于重度修枝和对照(P=0.024),分别为重度和对照的1.59和1.69倍.修枝可提高三倍体毛白杨材积生长,轻度修枝材积生长显著高于对照(P=0.008),较对照和重度修枝分别高140.66％和90.16％,重度修枝也较对照高26.56％.对照和轻度修枝叶片净光合速率较重度高9.43％ (P＞0.05),但在某些特殊点,不同处理间净光合速率差异显著.修枝对三倍体毛白杨树干边材液流无影响,未修枝处理较修枝平均高3.36％.总体来看,修枝可促进三倍体毛白杨林木生长,提高其整体水分利用效率,轻度修枝最佳.
