The Effect of Exogenous Sugar Supply and Nitrogen Deficiency on Dry Matter Allocation in Rape Seedlings Grown in vitro

Dry matter allocation is a very good indicator of conditions of both the mineral nutrition of plants and the photosynthetic conditions in vivo. We determined the response of dry matter accumulation and shoot/root ratio of rape seedlings (Brassica napus L.) to different levels of sucrose supply and nitrogen deficiency in vitro. The dry weight of roots and shoots increased significantly with increasing concentration of sugar in the medium from 0 % to 9 % (w/v) but shoot/ root ratio decreased. Nitrogen deficiency caused a further decrease in the shoot/root ratio. The results show that exogenous sugar supply can induce a similar shift in partitioning of dry matter as favourable photosynthetic conditions and that the response to exogenous sugar is influenced by nitrogen deficiency.