Abstract: The proline content of mesophytes, less-succulent xerophytes and succulent xerophytes were 0.42, 1.73 and 7.22 mg／g·dw·h 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 condition was higher than that under irrigation condition. The photosynthetic rates of less-succulent and succulent xerophytes were 16.74 and 14.04 CO2 mg／g·dw·h respectively, without clear difference between them. The photosynthetic rate of mesophyte (37.57 CO2 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 CO2 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 CO2 mg／g·dw·h respectively. This fact indicated that the carbon assimilatory process of mesophyte 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.

Key words: Proline, Photosynthetic rate, Respiratory rate, Chlorophyll