Abstract: Salix matsudana is the only tree species in Hangzhou Bay wetland of East China. From May to November 2007, the diurnal and seasonal dynamics of its photosynthes is were determined with Li-6400 Portable Photosynthesis System, and the relationships between the dynamics and environmental factors were analyzed by stepwise multiple-regression and path analysis. The results showed the daily mean value of net photosynthesis rate P_n for each month was in the sequence of August>September>July>June>May>October>November. The diurnal course of P_n had a unimodal pattern in May, June, October and November, and a mid-depression in July, August and September. The dynamics of P_n was very sensitive to the leaf temperature (T_l), vapor pressure deficit (VPD), and photosynthetic active radiation (PAR) in May, June, October and November, to VPD, T_l, and relative humidity (RH) in July, August and September, and to T_l and VPD in the whole growth period. It was suggested there existed greater variations in the diurnal and seasonal dynamics of P_n in the growth period of S. matsudana, and the effects of test environmental factors differed each other to some extent.

Key words: Polybrominated diphenyl ethers (PBDEs), Toxicological effect, Environmental exposure, Bioaccumulation