关键词: 铜尾矿, 重金属污染, 土壤酶活性

Abstract: Melatonin (MT) is an important factor protecting plants from a variety of abiotic stresses. To explore the effect of MT application on photosynthetic function of Solanum lycopersicum L. cv. We used 150 mmol·L^-1 NaCl as salt stress and 150 μmol·L^-1 MT as pretreatment toexplore the effect of MT on photosystem II in tomato (Liaoyuandouli) leaves under salt stress. The results showed that salt stress reduced chlorophyll content, photosynthetic function. The decrease of PSII activity was mainly due to the reduction in the activity of oxygenevolving complex (OEC) on donor side of PSII and the blockage of electron transfer from Q_A to Q_B on receptor side of PSII. The donor side of PSII was more sensitive to salt stress than the receptor side of PSII. In addition, the ability of PSII reaction center to harvest and utilize light energy, the concentration of reaction centers (expressed as per unit leaf area) and the ratio of excitation energy to absorbed energy were all decreased. However, MT application significantly reduced the magnitude of chlorophyll content reduction and photosynthetic rate. MT application can alleviate the damage on tomato caused by salt stress through balancing the electron transfer on donor side, receptor side and reaction center of PSII.

Key words: Copper tailing, Heavy metal contamination, Soil enzyme activities