Abstract:

To investigate the adaptive capacity to light irradiance, the author explored light-dependent the gas exchange and chlorophyll fluorescence properties in lex cornuta and Ilex Corunta Var. fortunei. The results showed that with increasing of light intensity under 28℃, there was a faster increase in net photosynthetic rate (Pn) in Ilex Corunta Var. fortunei, while a slower increase in lex cornuta, which indicated that the photosynthetic capacity in Ilex Corunta Var. fortunei was stronger in this region. However, the stomatal conductance (Gs), transpiration rate (Tr) and intercellular CO2 concentration (Ci) were higher, which indicated that the lower photosynthetic rate in Ilex Corunta was not resulted from the decrease of stomatal conductance. Further evidence by chlorophyll fluorescence showed that the efficiency of energy conversion of open PSⅡ (Fv'/Fm') and its electron transport rate (ETR) was higher, while non-photochemical quenching (NPQ) was lower in Ilex Corunta, as compared to that in Ilex Corunta Var. fortunei. And there were no significance difference in photochemical quenching (qP) in two groups. The results suggested that the higher assimilation rate in Ilex Corunta Var. fortunei was probably associated with carbon assimilation.