对全光照、林隙、林冠3种光照环境下6年生云南红豆杉的构型和叶水分特征研究结果表明:云南红豆杉的构型在不同光照条件下存在显著的可塑性变化,叶构件的水分特征也有不同程度的差异.全光环境下的云南红豆杉树体高大、树冠开阔,圆满度为0.97(约为林冠下的两倍)；全光下的总体分枝率为8.57,显著大于林隙的6.40和林冠下的4.81；全光中的1级枝长度、枝倾角、叶倾角等构型指标都显著大于林隙和林冠下的；3种光环境下各枝级的叶片分配存在明显的差异,全光下枝条的叶片数量是林隙的2.77倍,是林冠下的6.88倍,但它们都是1级枝的叶最多；叶构件的水分饱和亏缺有随着光照强度减弱而增大的趋势,组织密度、相对含水量、干鲜比则随着光照减弱而减小,表明叶片的抗旱保水和抵御水分胁迫的能力随着光照强度的增强而变大.云南红豆杉为适应不同光环境,在形态和生理方面都做出适应性调整.%The branching pattern and leaf water feature of Taxus yunnanensis in different light environment were studied in Jingdong of Yunnan Province. The results showed that the architectural model was modified plastically in response to different light conditions, the leaf water feature also has some differences. T. yunnanensis had great stature and wide crown in theses areas where the light is sufficient, the crown fullness ratio was 0,97(almost double those under canopy). The average overall bifurcation ratio in full light environment was 8.57, it was significantly bigger than 6.40 of gap and 4. 81 of under canopy, some other architectural parameters such as length of the first order branch, branch angle and leaf angle had the same trend. The leaves displayed significant differently in various light environments, the leaf number of branch in full light was 2. 77 times of that in gap and 6.88 times of that under canopy, but all of them had the biggest amount of leaves distributed at the first-order branches. The water saturation deficit increased with the continuous weakening of light intensity, while the tissue density , relative water content and ratio of dry weight to fresh weight reduced with the tapering off of light.It indicated that the leaf's ability of combating drought, retaining water and resisting water stress increased with the increase of the light intensity. These indicated that T. yunnanensis made some necessary changes in morphological and physiological aspects in order to accommodate it to the change of light environment.
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