【摘要】 利用Li-6400光合作用测定仪,西双版纳热带季节雨林林下细罗伞幼树(Ardisia tenera)在雾凉季(1月)、干热季(4月)和雨季(7月)的光合光响应特征及光合速率日变化被测定。结果显示:人工光源下,细罗伞幼树Pnmax、c、a均以雨季中最大,分别为2.782μmol/(m2.s)、1.233μmol/(m2.s)和0.007,各季节中LSP、LCP均偏低;林下自然光照环境中,3个季节细罗伞幼树Pn均出现双峰型特征,雾凉季、干热季和雨季的最大峰值分别为1.288μmol/(m2.s)、1.919μmol/(m2.s)、2.5μmol/(m2.s),雨季中一天中的Pn和Gs最大,雾凉季的Tr最小,但WUE却最高。林下细罗伞幼树光合特性随季节而发生显著变化,且表现出耐荫的特性,总体上细罗伞幼树对CO2的净吸收通量较低。更多还原

【Abstract】 Light response characteristics and diurnal variation of photosynthesis of young trees of Ardisia tenera were measured with Li-6400 in fog-cool season,dry-hot season and rain season in understory of tropical seasonal rain forest in Xishuangbanna.The results show that Pnmax,c and a of young tree of A.tenera in rain season are the highest,which are 2.782 μmol/(m2?s),1.233 μmol/(m2?s) and 0.007 respectively in artificial illuminant,and LSP and LCP are comparatively low in each season as a whole.In environment of natural illumination,the diurnal process of Pn for young tree living in the understory shows a "bimodal pattern" in fog-cool season,dry-hot season and rain season,and the peak values were 1.288 μmol/(m2?s),1.919 μmol/(m2?s) and 2.5μmol/(m2?s) respectively.Pn and Gs in rain season are the highest.Tr is the lowest,but WUE is the highest in fog-cool season.Thus,photosynthetic characteristics of young trees of A.tenera were largely influenced by change of seasons,and these characteristics reveal the shade-tolerant characteristics of young trees of A.tenera.Overall,the net flux that young trees of A.tenera absorb carbon dioxide is relatively low.更多还原