Abstract: Selecting three adjacent vineyards as test objects, this paper studied the effects of applying herbicide in growth season on the leaf photosynthetic apparatus and branch nutrient storage of grape Kyoho (Vitis vinifera×Vitis labrusca). In the vineyards T₁ andT₂ where herbicide was applied in 2009, the net photosynthesis rate (P_n) of grape leaves had a significant decrease, as compared with that in vineyard CK where artificial weeding was implemented. The leaves at the fourth node in vineyard T₁ and those at the sixth node in vineyard T₂ had the largest decrement of P_n (40.5% and 32.1%, respectively). Herbicide had slight effects on the leaf stomatal conductance (G_s). In T₁where herbicide application was kept on with in 2010, the P_n was still significantly lower than that in CK; while in T₂ where artificial weeding was implemented in 2010, the P_n and G_s of top- and middle node leaves were slightly higher than those in T₁, but the P_n was still lower than that in CK, showing the aftereffects of herbicide residual. The herbicide application in 2009 decreased the leaf maximum photochemical efficiency of PSⅡ(F_v/F_m) and performance index (PI) while increased the relative variable fluorescence in the J step and K step, indicating the damage of electron transportation of PSⅡ center and oxygen-evolving complex. Herbicide application decreased the pigment content of middle-node leaves in a dose-manner. Applying herbicide enhanced the leaf catalase and peroxidase activities significantly, increased the superoxide dismutase (SOD) activity of middle-node leaves, but decreased the SOD activity of top- and bottom node leaves. After treated with herbicide, the ascorbate peroxidase (APX) activity of middle- and bottom node leaves increased, but that of top-node leaves decreased. Herbicide treatment aggravated leaf lipid peroxidation, and reduced the soluble sugar, starch, free amino acids, and soluble protein storage in branches.

Key words: herbicide, grape, photosynthesis, nutrient storage