Germination-induced peptide pool regulate water homeostasis in plants.

摘要

Low molecular peptides from 3.0 kDa to 0.5 kDa were isolated from germinating seedlings (after 64 hours of soaking) of Vigna radiata (L) Wilczek cv. sonali B1 and purified through ion-exchange, ultrafiltration and gel permeation chromatography. Heterogeneous peptide profile of germination pool was detected through paper chromatography and capillary zone electrophoresis. Isolated peptides were further purified through paper chromatography in accordance with their four distinct R_f zones. Peptide fractions isolated from first and third lower R_f zones appreciably increased the flow rate, absorption, transpiration of solute, root and shoot lengths of seedlings. Dark induced stomatal aperture opening and enhancement of protoplast volume was also observed by the same peptides. These peptides antagonized the inhibitory action of ABA and mimicked the bioactivity of cytokinin. cGMP may be the mediator of this signal as established when LY 83583 decreased the protoplast volume after peptide application. Amino acid analysis of third R_f zone peptide strongly support the immunoreactive atrial natriuretic behaviour of peptides. Peptides representing second lower R_f zone did not display bioactivity and peptides from highest R_f zone decreased the above biological perception. In general, functional diversity of peptide pool is particularly related with the physiological conditioning of water and solute homeostasis of plants.