Abstract:Armeniaca vulgaris Lam.is the most important constructive species of wild fruit forests in the Tianshan Mountains,Northwest China.Our objective was to clarify the existence status and photosynthetic characteristics of A.vulgaris and the relationships between wild fruit forest and some eco-physiological factors.Saplings of A.vulgaris were selected at the Center for Research and Development of Wild-Fruit Forest Resources,Yili Kazak Autonomous Prefecture,Xinjiang Province,China.And the response of photosynthetic rate to photosynthetic effective radiation,diurnal change of photosynthetic rate and eco-physiology factors,were analyzed in situ by Li-6400 Portable Photosynthesis Analysis System under natural conditions,Relative analysis,path coefficient analysis and stepwise regression equation were used to discuss how related factors influenced diurnal changes of photosynthetic rate.The results showed that:(1)The maximum net photosynthetic rate (Pnmax) and light compensation point (LSP) were 12.63 and 1 389.44 μmol·m-2·s-1,respectively.It is a heliophilous plant.(2)Diurnal change of Pn showed a unimodal curve in sunny days.But the diurnal change of Pn showed a bimodal curve in cloudy days,and there was obvious midday depression of photosynthesis,because of the non-stomata limitation,which indicated the degree of photoinhibition reduced in cloudy days.(3)The reduction of photoinhibition was caused by the decrease of leaf temperature (Tl).Stomatal conductance was positive correlation with both Pn and transpiration rate (Tr).With the increase of Tl,Pn,Gs and Tr exhibited a unimodal curve in sunny days.However,in cloudy days,Pn and Tr was positive correlation with Tl,whereas Gs was negative with Tl.The decrease of Gs due to Tl exceeding the optimal value was an important reason for the appearance of severe photoinhibition in sunny days.The decrease of Tr by closing stomata quickly controlled the lose of water to the utmost extent,in spite of leading to the increase of Tl and decrease of Pn,which was one of the important physiological characteristics for A.vulgaris to distribute the arid adret.(4)The main physiological factor affecting the characteristic of Pn of A.vulgaris was Gs,Ci was the main limiting factor;and the main ecological factor was RH,Ta was the limiting factor both in sunny days and cloudy days.The results indicated that A.vulgaris adapt to high-light’s capability,it is a heliophilous plant,and the photosynthesis were no visible inhibition in cloudy days,while the environmental conditions under forest crown artificial accommodated to suit the self-restoration of A.vulgaris population.