Abstract: Taking the tissue-cultured seedlings of grape cultivar Red Globe as test objects, this paper examined the effects of their root aqueous extracts on seedling’s growth, with the allelochemicals identified by LC-MS. The results showed that 0.02 g·ml^-1(air-dried root mass in aqueous extracts volume; the same below), 0.1 g·ml^-1, and 0.2 g·ml^-1 of the aqueous extracts inhibited the growth of the seedlings significantly, and the inhibition effect increased with increasing concentration of the extracts. The identified allelochemicals of the extracts included ρ-hydroxybenzoic acid, salicylic acid, phenylpropionic acid, and coumaric acid. Pot experiment showed that different concentration (0.1, 1， and 10 mmol·L^-1) salicylic acid and phenylpropionic acid inhibited the seedling’s growth remarkably. With the increasing concentration of the two acids, the plant height, stem diameter, shoot- and root fresh mass, leaf net photosynthetic rate and starch content, and root activity of the seedlings decreased, while the leaf soluble sugar and MDA contents increased. No obvious change pattern was observed in leaf protein content.

Key words: grape, root extracts, allelopathy, allelochemicals, nitrogen application rate, straw returning, late sowing winter wheat, nutrient balance.