Effectors for the osmoinduced proline response in higher plants

Abstract

Rape leaf discs incubated in vitro in the presence of some osmoticums in concentration superior to 0.4 M (i.e. π # −1 MPa) accumulate proline at a high rate after a 4 h induction period. This response provides the opportunity investigate factors involved in the control of the proline response. With NaCl 300 mM as osmoticum, the final amount of proline is determined by that of sugars available in the tissues. Sucrose, D-glucose and D-fructose used as osmoticums are more efficient than mannitol and sorbitol. D-galactose proves to be a good inductor whereas D-mannose and L-sorbose are inoperative. D-xylose induces a response whereas D (-)ribose and D (-)arabinose are inefficient