The role of apoplast in distribution of assimilates along the flax plant

摘要

The peculiarities of distribution of photosynthetic products along the flax plant (Linum usitatissimum L.) under two levels of nitrogen nutrition has been investigated. The labelled assimilates were extracted from apoplast space of various plant parts using the pressure chamber and infiltration. It was shown that ~(14)C-assimilates, entering in apoplast space of ~(14)C-donor section of the medium part of flax shoot, quickly appeared (in 5 minutes) in the upper part of the shoot. In the apoplast of the upper pan of a plant the number of labelled assimilates was several times more than in the apoplast of the lower one. When entering in the upper leaves they did not stay there but were retransported in the descending direction. Intensified nitrogen nutrition decreased the share of labelled compounds in the apoplast and retarded the transport of assimilates from the donor part of the plant. The additional plant fertilizing by KCl solution that was carried out outside the roots, removed the negative effect of nitrogen and markedly stimulated transport of labelled products of photosynthesis. The possibility of distribution of assimilates along the plant with transpiration water flow and the involvement of invertase in the formation of retarding action of intensified nitrogen nutrition on the export of assimilates were discussed.