The Effect of Leaf Age and Position on the Dynamics of Microbial Populations on Aerial Plant Surfaces

Abstract

Epiphytic microbial communities of terrestrial plants are non uniformlydistributed in space and in time on leaf surfaces. The size and compositionof microbial populations vary under the influence of biotic and abioticfactors related to the micro-organisms themselves (traits conferringepiphytic fitness, nutritional resource utilisation, abilities tocompete for space, resistance or production of toxic compounds),to the host (its genotype, the age and the position of the leaves),and to the environmental conditions (micro- and macro-climate, activityof vectors and pathogens, application of pesticides and other chemicals).Moreover, the microbial population dynamics results from four processes-immigration, emigration, multiplication and death of cells as discussedin a previous chapter (Lindow, this volume) � which are under theinfluence of the previously mentioned factors.