Effects of wheat bran extracts on seedling growth of plants

The effects of wheat bran extracts were examined on root and shoot growth of five plant spp. (rape, garden cress, lettuce, cockscomb, and sesame) to identify the strongest growth inhibition or promotion and the most sensitive species. The 90% water [MeOH:H₂O = 10:90 (v/v)] extracts were most inhibitory to root and shoot growth of rape, garden cress, lettuce and sesame, followed by methanol and acetone extracts. The inhibition was concentration-dependent. The 90% water extracts considerably stimulated the shoot growth of cockscomb, followed by acetone and methanol extracts. The 90% water extracts from 3 to 30 g eq./l concentrations increased the growth, but higher concentrations were inhibitory. Thus, wheat bran contains water-soluble allelochemicals that exhibit plant selectivity. The extract concentrations required for 50% inhibition were smaller for root growth than for shoot growth, with the exception of acetone extracts for garden cress and cockscomb. Thus, wheat bran or its water extracts can be important tool for weed suppression or crop promotion in agroecosystems.