Abstract

In their environment, plants are continuously submitted to natural stimuli such as wind, rain, temperature changes, wounding, etc. These signals induce a cascade of events which lead to metabolic and morphogenetic responses.In this paper the different steps are described and discussed starting from the reception of the signal by a plant organ to the final morphogenetic response. In our laboratory two plants are studied: Bryonia dioica for which rubbing the internode results in reduced elongation and enhanced radial expansion and Bidens pilosa for which the response occurs at distance, hence pricking the cotyledon of a plantlet induces the growth inhibition of both the hypocotyl and the axillary bud of the pricked cotyledon