Studies on Photosynthetic Characteristics and Adaption to Environment of Some Alpine plants in Qinghai-Xizang Plateau

Abstract

Mainly the alpine plants in Qinghai¿Xizang plateau including Salix gilashanica, Salix pilosomicrophylla, Rhododendron coriaceum, Rhododendron faucium, Rhododendron nivale, Quercus aquifolioides were compared with the same genera, non-alpine plants including Salix babyleuica, Salix matsudana, Rhododendron maoronulatum, Quercus liaotangensis for studying their photosynthetic characteristics and photosynthetic adaptability to high mountain environment. The results showed that chlorophyll content of the leaves and chloroplasts tended to be lower in alpine plants than in non-alpine, but the chlorophyll a to b ratio and the carotenoid relative content were higher in alpine plants than non-alpine plants. The decreased trends of Fv/Fm and Fv/Fo (parameter of kinetics of Chl a fluorescence induction) of detached leaves indicated that the potential photosynthetic capacity of alpine plants did not be higher than those non-alpine plants. But that the PSI/PSII ratio was low and related content of PSII in the chloroplasts was high from alpine plant as indicated by fluorescence spectra. Separation and quantification of the various carotenoids was completed by the high performance liquid chromatography. The results show that the chloroplast of S. gilashanica and Q. aquifolioides contained greater amounts of the components of the xanthophyll cycle than the same genera, non-alpine plants S. matsudana and Q. liaotangensis. But the content of the components of the xanthophyll cycle in the chloroplast of R. coriacenm and R. nivale were lower than the same genera non-alpine plants R. macronulatum. The results showed the xanthophyll cycle may be very important in adaptation of the partial alpine plants to high light radiation.