季节雨林云南玉蕊幼树光合光响应的季节动态

[目的]了解热带季节雨林幼树个体光合光响应的生物学特性,为全球气候变化下热带雨林保护提供科学依据。[方法]在西双版纳热带季节雨林中选择林下云南玉蕊幼树,分别于雾凉季、干热季、雨季,测定其光合光响应特征的季节变化动态。[结果]云南玉蕊幼树林下Pnmax为雨季最大,干热季和雾凉季次之,分别为4.08、2.89和1.81μmol/(m2.s),季节间具显著差异;Gs和Tr以雨季相对最高,WUE以干热季为最高,Ci以雾凉季为最高,它们在人工光源下的最大值分别为0.18 mmol/(m2.s)、1.59 mmol/(m2.s)、7.35μmol/mmol和455μmol/(m2.s);Ci随光强及季节的变化与WUE呈相反趋势,而Gs与Tr变化趋势基本一致。[结论]热带季节雨林云南玉蕊幼树林下光合光响应特征具明显季节性,雨季中有比其他季节更为旺盛的光合特征,且幼树具有耐荫的特性。

西双版纳热带季节雨林4种树种幼苗生长死亡对海拔变化的反应

在西双版纳山地选取3个海拔梯度,对热带季节雨林4种主要树种进行幼苗移栽试验,观测幼树生长、死亡沿海拔梯度的变化,目的在于明确海拔变化对热带季节雨林主要树种幼苗生长、死亡的影响,热带季节雨林主要树种幼苗的生长是否在低海拔地区优于在高海拔地区。结果表明,4种幼苗对海拔变化的反应并不相同。绒毛番龙眼和云南玉蕊幼苗的生长和存活主要是受到温度的限制,随海拔的变化表现出显著的差异,这两种幼苗在低海拔上的生长显著优于在中、高海拔上,而云南肉豆蔻和小叶红光树没有表现出在低海拔上优于中、高海拔的特征,这可能是由于它们不适应强光照的生活环境而造成的。

Seasonal Dynamics of Photosynthetic Response for Young Tree of B. macrostachya in Seasonal Rain Forest

[Objective] The aim was to study on biological characteristics of photosynthetic response for young trees of B. macrostachya in seasonal rain forest, providing scientific reference for protection of tropical rain forest under change of global climate. [Method] Young trees of B. macrostachya in Xishuangbanna tropical forest were chosen to research in foggy season, dry and hot season, and rainy season to measure dynamics of season changes. [Result] For young trees of B. macrostachya in Yunnan Province, Pn max was the biggest in rainy season, followed by dry and hot season and foggy season at 4.08, 2.89 and 1.81 μmol/（m·s） respectively; Gs and Tr in rainy season were the highest and WUE in dry season was the highest; Gi achieved peak in foggy season, of which the highest values were 0.18 and 1.59 mmol/（m 2 ·s）, and 7.35 μmol/mmol and 455 mmol/（m 2 ·s）; Ci showed an opposite trend with that of WUE, and Gs and Tr changed similarly. [Conclusion] Young trees of B. macrostachya in seasonal rain forest are of significant seasonal change in photosynthetic response, and young trees are shade tolerant.