The Characteristic of Cluster Analysis of 21 Kinds Leguminosae Pasture Fluorescence Parameters in Cele Oasis

Cele Oasis is located near the south border of Taklimakan desert, characterized by harsh environmental conditions such as strong radiation, high temperature, drought, low soil fertility and so on. To address the adaptability of commonly cultivated Leguminosae pasture species to local environment, 21 species, growing at the edge of Cele oasis were studied and were compared in terms of fluorescence parameters to investigate the effect of habitats on photosystem II (PS II). 21 kinds Leguminosae pasture species, Fast photosystem II (PS II) chlorophyll fluorescence kinetics were monitored after adaptation in darkness for 20 min and analysed the characteristic of cluster analysis. The measured physiological parameters differed greatly in all the Leguminosae pasture in the Cele Oasis, and it can be split into four groups. It showed obviously the first group had the highest F_o, ABC/RC, TR_o/RC, DI_o/RC, and lowest F_m, F_v/F_o, F_v/F_m, RC/CS_o, ET_o/RC, the fourth group was on the contrary, second group and third group were between them. These parameters also showed large difference in variation amplitude. These results suggested that all the pasture species were suffered from the environmental conditions of Cele Oasis to some extent, as indicated by inactivation of PSII reaction center and depression of electron transport chain. The PSII of first, second, third fourth group is limited more and more significantly. We should according to different specific analysis when using chlorophyll fluorescence kinetics curve to evaluation plant photosynthetic capacity.