Effects of aqueous extracts from Paris polyphylla seeds on seed germination and seedling growth of three kinds of plants

Chinese cabbage (Brassica pekinensis), mung bean (Vigna radiata), and wheat (Triticum aestivum) seeds were treated with different concentrations of aqueous extracts from Paris polyphylla episperm and endosperm. We studied the germination rate, seedling growth, and protective enzyme activity of the three plants through exposure to the aqueous extracts, and explored the activity and ingredients of endogenous inhibitors in P. polyphylla seeds. Results showed that different extract concentrations had certain effects on the germination rate, seedling height, seedling root length, and fresh weight of the seeds from the three plants. The strength of these effects increased at relatively low concentrations and decreased at relatively high concentrations. The effect on Chinese cabbage was stronger than that on wheat and mung bean, and the effect of the extract from the endosperm was significantly greater than that from the episperm. The extracts also influenced the protective enzyme activities of Chinese cabbage, mung bean, and wheat. Superoxide dismutase (SOD) and peroxidase (POD) activities significantly increased with increasing concentrations. Catalase (CAT) activity of Chinese cabbage and wheat significantly decreased, whereas that of mung bean showed a non-significant increase. GC-MS was applied to test eight substances from the endosperm aqueous extract and two from the episperm aqueous extract, with benzoic acid demonstrating germination inhibitory activity. Therefore, P. polyphylla seeds contain an endogenous inhibitor, whose activity changes with concentration, and may be the cause of seed dormancy. Aqueous extracts from P. polyphylla seeds may affect the normal growth of recipient seedlings by affecting the protective enzyme activity of recipient seedlings; furthermore, organic acids may be endogenous inhibitors of P. polyphylla seeds.