The photosynthetic characteristics of Idesia polycarpa Maxim. Var. vestita Diels in different periods

the purpose of this paper is to explore the characteristics of photosynthesis in Idesia polycarpa Maxim. Var. vestita Diels in different periods. The diurnal changes and annual changes in photosynthesis were measured using a CIRAS-2 portable photosynthesis system, its diurnal and annual changes and the relationships between the photosynthesis changes and influencing factors were studied systematically. The results showed that the photosynthetic rate of Idesia polycarpa Maxim. Var. vestita Diels presented a single peak curve from May to October and the highest photosynthetic rate arrived at 09:00, and the main limit factor for diurnal changes of photosynthesis is non-stomatal factor (the photosynthetic capacity of mesophyll cells). In the whole growing season, photosynthetically active radiation (PAR) and stomatal conductance (Gs) were the most significant environmental and physiological factors influencing the net photosynthetic rate (Pn), and stomatal limitation is one of the reasons for the reduce of photosynthesis in different periods.