Abstract: In this paper, the net photosynthetic rate (P_n), actual photochemical efficiency of PSⅡ(Φ_PSⅡ), photochemical quenching(q_P), and maximal photochemical efficiency of PSⅡ in light (F_v^′/F_m^′) of apricot (Prunus armeniaca) leaves in solar greenhouse were measured, and the effects of low temperature (7 ℃) and weak light (200 μmol·m^-2·s^-1 PFD) on the photoinhibition of PSⅠ and PSⅡ were investigated. The results showed that the optimal temperature for the photosynthesis of apricot leaves was around 25 ℃, and the photosynthetic capacity was reduced greatly by the low temperature and weak light, inducing a markedly increased excitation press (1-q_P) and in turn, resulting in photoinhibition. The functions of both PSⅠ and PSⅡ were damaged by the low temperature and weak light. Comparing with those only subjected to low temperature, the leaves subjected to both low temperature and weak light had a decreased activity of PSⅠ, with a decrement of 2826% within 2 h, but their maximal photochemical effeciency of PSⅡ (F_v/F_m) had little change in the same period, suggesting that under low temperature and weak light, PSⅠ was more suffered from photoinhibition than PSⅡ.

Key words: root exudate, belowground ecology, culture substrate, collection technique