水分对杜仲截干萌条光合特性及生长的影响

Photosynthetic characteristics and growth of sprout of Eucommia ulmoides under different water conditions

【目的】确定杜仲截干萌条林的适宜供水量,为杜仲人工林的经营提供理论依据。【方法】通过对6年生杜仲进行截干处理,研究了生长季单株供水量分别为0.14（Ⅰ级）、0.28（Ⅱ级）、0.42（Ⅲ级）、0.56（Ⅳ级）m3条件下杜仲萌条的生理及生长指标。【结果】不同水分处理时,杜仲净光合速率日变化曲线不同,自然条件及供水不足（处理Ⅰ、Ⅱ）条件下,杜仲净光合速率日变化呈“双峰”曲线,表现出明显的光合“午休”现象；充足供水（处理Ⅲ、Ⅳ）时,杜仲净光合速率日变化呈“单峰”曲线,“午休”现象消失,且净光合速率提高,6月份是杜仲净光合速率最大的时期。人工供水能增加杜仲萌条的生长,6-9月份,处理Ⅰ、Ⅱ、Ⅲ、Ⅳ的杜仲萌条枝长总生长量分别较对照增加8.6%,33.9%,70.7%和41.6%,新枝基径总生长量分别较对照增加5.7%,51.4%,114.2%和108.6%。人工供水可以显著增加杜仲二次分枝的数量,处理Ⅲ二次单株分枝数、平均枝条长度、叶干重分别达到21个,18.3 cm,8.4 g/株。【结论】单株供水量为0.42 m3最有利于杜仲萌条生长,二次分枝数最多,平均枝条长度最长,单株叶干重最大。

【Objective】 The study confirmed the optimum irrigation norms of the stump plant of Eucommia ulmoides,and provided theory basis for the management of the man-made E.ulmoides forest.【Method】 6-yeay-old E.ulmoides were cut off,the photosynthetic and growth indexes of stump plant were detemined when the supply water was 0.14（treatmentⅠ）,0.28（treatmentⅡ）,0.42（treatment Ⅲ）,0.56（treatment Ⅳ）m3 in growing season.【Result】 The result showed that the diurnal courses of the photosynthesis rate were double peak in normal or supply little water condition.While the photosynthesis rate diurnal courses were single peak in the condition of plenteous water which the supply water was 0.42-0.56 m3 per tree from May to August,and the photosynthesis rate increased.Artificial watering could increase the growth of sprout.Form June to September,the length and diameter of new branch in the treatments ofⅠ,Ⅱ,Ⅲ and Ⅳ increased by 8.6%,33.9%,70.7%,41.6% and 5.7%,51.4%,114.2%,108.6% respectively compared with that of the control.【Conclusion】 The optimum irrigation norms were 0.42 m3 per tree,and the number and length of second ramification were the most,and the dry weight of the leaves were bigger.