ABSTRACT
Prolonged cell growth also requires the uptake of solutes to buffer osmotic potential against the diluting effects of volume increase and to provide substrates for energy metabolism and synthesis of new wall and cytoplasmic constituents. Two broad groups of factors modulate responses to plant hormones: first are those which determine whether or not a given hormone reaches a responsive target site and if so, in what quantities. Second are those which affect hormone-receptor interactions and which control the steps downstream of the occupied receptor which ultimately lead to the response. The distances between sources and sinks relationships in a plant depend on its morphological structure. Compared with sinks in which cell expansion predominates, there is a dearth of information available on the role of endogenous hormones in the regulation of assimilate accumulation by maturing storage sinks. The mechanism by which etiolation of intact plants dramatically stimulates internode elongation and invertase activi.
