在水生与气生状态下石莼光合作用对光照和温度的响应(英文)  

Photosynthetic Responses to Light and Temperature in Ulva lactuca Under Aquatic and Aerial States

作　　者：邹定辉[1] 高坤山[1] 

机构地区：[1]汕头大学科技中心海洋生物研究所,广东汕头515063

出　　处：《植物学通报》2003年第6期713-722,共10页Chinese Bulletin of Botany

基　　金：国家自然科学基金资助项目 ( 3 983 0 0 60 )

摘　　要：如何对付由于高潮时的水生状态与低潮时的气生状态高频率循环所导致的不同环境条件 ,是潮间带海藻的光合作用所面临的独特问题。对采自汕头沿岸的石莼 (Ulvalactuca)在水生和气生不同状态下光合作用对光照和温度的响应特性进行了测定 ,以探讨这种常见的潮间带绿藻在潮汐循环背景下的光合特性。在气生状态下 ,光饱和净光合速率 (Pmax)随气生暴露时间的变化模式可以很好地用三次方程进行描述 ,而温度影响方程的系数 ;当水分损失为 1 5 %时 ,石莼的Pmax增加至最大值 ,然后Pmax随进一步脱水而下降 ,在水分损失为 80 %时下降至 0。温度对Pmax的影响在水生状态下比在气生状态下更大。气生状态下 (充分水化 )Pmax在 1 0℃时显著小于水生状态下的值 ,而在 30℃时则相反。在 1 0℃时 ,气生干出时间在 6h以内 ,或在 2 0℃时 ,气生干出时间在 2 .2h以内 ,石莼的净碳固定量在气生状态下比在水生状态下要大 ;而在 30℃时 ,在气生状态下的净碳固定量比总是小于在水生状态下的净碳固定量。认为石莼在低潮气生状态下与在高潮水生状态下光合特性及净碳固定存在差异 。The varied environmental conditions imposed by high frequency cycles of aquatic and aerial states is a unique problem confronted by the photosynthesis of intertidal macroalgae. The photosynthetic responses to light and temperature were examined in Ulva lactuca collected along the Shantou coast of China, to establish the photosynthetic characteristics in relation with tidal cycles for this common intertidal green macroalga. Under aerial state, the relationship of light_saturated net photosynthetic rates (P max ) and exposure duration could be modeled by the third_order polynomial equation, and temperature affected the coefficients of the equation. An increase of photosynthetic activity was evident at 15% water loss, and the rates decreased thereafter with further desiccation till to zero at 80% water loss. P max was much more affected by temperature under aquatic state than under aerial state. Aerial P max (fully hydrated state) was significantly greater at 10℃, but was considerably lower at 30℃, compared with aquatic P max . The net carbon fixation under aerial state was greater than that under aquatic state within 6 h of photosynthetic duration at 10℃, whereas was slightly higher than that under aquatic state within 2.2 h at 20℃. At 30℃, the net carbon production was always lower under aerial state than under aquatic state. It was concluded that the photosynthesis and carbon budget of Ulva lactuca under aquatic state differed from that under aerial state, and such difference was associated with the conditions of ambient temperature and water statues of thalli.

关 键 词：石莼 光合作用 光照 温度 水生 气生 碳预算 

分 类 号：Q945[生物学—植物学]