Abstract: To reveal the effects of high temperature and high humidity on light response of photosynthesis of tomato leaves, an experiment with tomato cv. ‘Jinfen 5’ was carried out in artificial climate chamber. We set a high temperature level of 41 ℃ (daytime)/18 ℃ (nighttime), three levels of relative air humidity of daytime (50%±5%, 70%±5%, 90%±5%), and four levels of experimental duration (3, 6, 9, 12 d), with 28 ℃/18 ℃, 50±5% as control (CK). The light response curve of leaves was measured. We selected CK and different treatments with air humidity levels at 6 days and 12 days as examples, and compared the function of four photosynthetic models. The model with the best simulation effect was used to simulate the light response parameters. The results showed that different models had different adaptability to different high temperature and high humidity. Different light response parameters of the simulation results varied across the models. Comprehensively, the modified rectangular hyperbola model was the best, followed by rectangular hyperbola model, non-rectangular hyperbola model, the exponential model. With the increases of humidity, α, P_max, LSP first increased and then decreased, LCP first decreased and then increased, and R_d had no obvious pattern. Our results confirmed that when the maximum air temperature rose to about 41 ℃, appropriate increase in air relative humidity to 70%±5% could effectively reduce the heat stress on the damage to photosynthetic mechanism of tomato.

Key words: ecological restoration, Tamarix ramosissima plantation, saline-alkali land, distribution of soil moisture and salt, row distance