Abstract: In order to understand the salt-tolerance of poplar, the seedlings of poplar cultivars Nanyang No. 1 and Nanyang
No. 2 bred by the Jiangsu Provincial Key Laboratory of Marine Biology were taken as the test materials to study their dry weight, water potential, chlorophyll content, chlorophyll fluorescence parameters, and light energy absorption and distribution under the stress of different concentrations NaCl. At low concentration (75 mmol·L^-1) NaCl, the plant dry weight, chlorophyll content, q_P, Yield, and ETR of Nanyang No. 1 were significantly lower than those of Nanyang No. 2. The decrement of the water potential of Nanyang No. 1 was higher than that of Nanyang No. 2, while the F_m/F_v and F_m′/F_v′ of the two cultivars had less change. At high concentration (150 mmol·L^-1) NaCl, there were no significant differences in the inhibitory effects of salt stress on Nanyang No. 1 and Nanyang No. 2. Under salt stress, Nanyang No. 2 had higher average value of P_c but lower proportion of H_d than Nanyang No. 1, while the average value of E_x of the two cultivars had little difference. Above all, due to the higher activity of photosystem Ⅱ, Nanyang No.2 had higher salt-tolerance than Nanyang No. 1.

Key words: tea garden soil, planting years, pH buffer capacity.