Effects of aqueous extracts of Paeonia decomposita seeds on germination and some metabolic activities associated with growth of wheat seedlings.

Paeonia decomposita is a perennial deciduous shrub with great ornamental and medicinal values. Unfortunately, the distribution region, population size and individual numbers of P. decomposita rapidly decrease in the wild. It is a particularly rare, highly endangered, protective plant endemic to Southwest China. To understand the causes of seed dormancy of P. decomposita, the effects of aqueous extracts of the seed coat, endosperm of P. decomposita on germination, seedling growth and amylases activities of wheat seeds were examined in this paper. The results showed that the seed, especially the endosperm tissue of P. decomposita contained substances that strongly suppressed seed germination. The crude extract of endosperm of P. decomposita, which significantly reduced the activities of α and ß-amylase, showed a more significant inhibition than that of seed coat at the same dose. It was concluded that the presence of inhibitory substances in seed, especially in endosperm tissue, seem to be responsible for P. decomposita seed dormancy.