喜树光合速率日变化及其影响因子的研究  

STUDIES ON THE DIURNAL CHANGES OF NET PHOTOSYNTHESIS RATE AND THE EFFECT OF ENVIRONMENTAL FACTORS OF CAMPTOTHECA ACUMINATA

作　　者：冯建灿[1] 张玉洁 

机构地区：[1]河南农业大学,郑州450002 [2]河南省林业技术推广站,郑州450008

出　　处：《林业科学》2002年第4期34-39,共6页Scientia Silvae Sinicae

摘　　要：本文对喜树光合速率 (Pn)日变化规律进行了研究 ,结果表明在晴天条件下 ,喜树Pn日变化为双峰曲线 ,具有典型的“午休”特征。阴天时则为单峰型。影响喜树叶片Pn日变化的主要生态因子是光通量密度和相对湿度。造成光合作用“午休”的内在原因不是气孔导度下降 ,减少了CO2 的供应量 。Camptotheca acuminata was an important medicinal tree as its camptothecin with anti tumor activity. The diurnal changes of net photosynthesis rate ( P n) in leaves of C. acuminata under natural condition were studied in this paper by CI 301 CO 2 analyzer. The results showed that the curve of diurnal variation of P n was demonstrated two peaks in clear day, which appeared at 10:00 and 16:00 respectively. The first peak value was 7 9075?μmol CO 2·m -2 s -1 and the second one was 3 7340?μmol CO 2·m -2 s -1 . There was a clear depression at noon, which was 2 4470?μmol CO 2·m -2 s -1 appeared at 14:00. Only one peak had the curve of P n in cloudy day, which occurred at 12:00 Daily average P n in clear day was 4 3300?μmol CO 2·m -2 s -1 , and that of cloudy was 3 7500?μmol CO 2·m -2 s -1 Photon flux density ( PFD ) and relative humidity played very important roles in P n changes among the ecological factors. Depression of P n was not caused by the decreasing of stomatal conductance that would decrease the CO 2 supply. Factly it was regulated by nostomatal factors.

关 键 词：影响因子 喜树 光合速率 日变化 药用植物 

分 类 号：S792.99[农业科学—林木遗传育种]