广西植物2000，Vol.20Issue(1)：52-58,7.
蜡梅光合与蒸腾速率日变化的初步研究
A preliminary study on the diurnal variation of net photosynthetic rate and transpiration rate for Chimonanthus praecox
李菁 1刘应迪 1陈功锡 1陈军 1朱杰英1
作者信息
- 1. 吉首大学生态研究所,湖南吉首,416000
- 折叠
摘要
Abstract
Abstract:The measurement of the net photosynthetic rate (Pn) and transpiration rate (Tr) for Chimonanthus praecox (L.) Link. under the natural conditions on sunny and cloudy days was carried out. The influences of environmental factors on diurnal variation of Pn and Tr for C. praecox were also analyzed in this paper. The present experimental results show: (1) The diurnal courses of the Pn for C. praecox on sunny and cloudy days were both double-ridged curves. On sunny days the two peak values of Pn appeared earlier and the general Pn value was higher than that on cloudy days. The phenomenon of midday depression of photosynthesis was obviously observed on sunny days. (2) The diurnal course of Tr for C. praecox on sunny days was of a single-ridged-form. The peak value of Tr reached beyond 10 mmol H2O m-2s-1 under the condition of intense light and high temperature in the afternoon. On cloudy days, the Tr curve was smooth. The transpiration was weak, below 0.8 mmol H2O m-2s-1 during a whole day. (3) The Pn of the wild C. praecox reached as high as 23.6 μmol CO2 m-2s-1 when the photosynthetic active radiation (PAR) was 800～900 μmolm-2s-1, air temperature (Ta) 28 ℃, relative humidity (Rh) 75%. The light saturation point and light compensation point of C. praecox were quite low, about 900 μmolm-2s-1 and 20 μmolm-2s-1 respectively. (4) PAR and Ta were dominant ecological factors limiting the diurnal variation of Pn and Tr for C. praecox. This plant was sensitive to high temperature and intense light. When PAR exceeded the light saturation point and Ta surpassed 42 ℃, the transpiration increased rapidly while the energy transformation and water use efficiency (WUE) decreased remarkably, the photosynthetic capacity was much weakened, all these above lead to the sharp descend of Pn.关键词
蜡梅/净光合速率/蒸腾速率Key words
Chimonanthus praecox/net photosynthetic rate/transpiration rate分类
农业科技引用本文复制引用
李菁,刘应迪,陈功锡,陈军,朱杰英..蜡梅光合与蒸腾速率日变化的初步研究[J].广西植物,2000,20(1):52-58,7.
