Seasonal changes of leaf rna / dna ratio and rna / protein ratio of four species plants from the Alxa Desert

To comprehensively understand the natural succession of plant communities in the Alxa Desert, we studied the seasonal changes for RNA, DNA and protein contents, and the ratios of RNA / DNA ratio and RNA / protein ratio of constructive species, and compared these differences at different successional stages. The study site, located at 38毅24忆59义 N, 105毅43忆31义E, is 8 km away from the Bayinhaote town of Alxa Left Banner of Inner Mongolia Autonomous Region, China. The succession series of plant community in this study area are as follows: In the early successional stage, community is dominated by Artemisia sphaerocephalla; at mid鄄successional stage, the plant communities are dominated by A. ordosica and A. frigida; and at late鄄successional stage, it developed into a relatively stable Oxytropis aciphylla community. In A. ordosica + A. frigida community, the A. ordosica was furthermore replaced by A. frigida. As to the cause for plant community succession, the difference of plant relative growth rate for the replaced species and / or substitute species is usually considered to be one of the major factors. Theoretically, plant RNA / DNA ratio and RNA / protein ratio may be