C OMPARATIVE STUDIES ON RELATIONSHIPS BETWEEN PROLINE ACCUMULATION AND PHOTOSYNTHESIS,RESPIRATION AND CHLOROPHYLL CONTENT OF SOME PLANT SPECIES IN THE MIDDLE PART OF THE DESERT ZONE IN CHINA
Liu Jia-qong Li Zhi-jian Pu Jin-chun Liu Xin-min (Lanzhou Institute of Desert Research,Academia Sinica) Zheng Si-di (Biology Department of Inner Mongolia University,Hohhot)
The proline content of mesophytes,less-succulent xerophytes and succulent xerophytes were 0.42,1.73 and 7.22 mg/g·dw respectively.The latter is 17 and 4 times both of the formers. The proline content of xerophytes-both succulent and less-succulent,under non-irrigation con- dition was higher than that under irrigation condition. The photosynthetic rates of less-succulent and succulent xerophytes were 16.74 and 14.04 CO_2 mg/g.dw.h respectively,without clear difference between them.The photosynthetic rate of mesophyte (37.57 CO_2 mg/g.dw.h) was more than 2 times that of two types of xerophytes. The respiratory rate of less-succulent xerophytes,succulent xerophytes and mesophytes were 6.27,4.73 and 7.60 CO_2 mg/g.dw.h respectively.The ratios of photosynthetic rate to respiratory rate in less-succulent xerophytes,succulent xerophytes and mesophytes were 2.50,3.09 and 4.59 CO_2 mg/g.dw.h respectively.This fact indicated that the carbon assimilatory process of meso- phyte was evidently higher than the respiratory process for all the two types of plants.There was no obvious difference between the total contents of chlorophyll in the three types of plants.