STUDY OF LOCAL ENVIRONMENTAL CONTROL OF ROOT SYSTEM ARCHITECTURE

Abstract

Plants are exposed in a heterogeneous environment in nature, especially the root system. In a relatively small volume, soils vary greatly in texture, nutrient contents, pH, and moisture content, all of which has a great impact on shaping root architecture. Work presented in this thesis reveals that under normal growth conditions local water heterogeneity helps to guide new organ development in the plant in addition to influencing root growth direction. Auxin is the primary hormone responding to moisture and promotes biased lateral root development towards moisture. Additionally, this work also shows that ABA might be the involved in sensing drought/moisture in the outer tissue layer. Together this thesis reveals some mechanisms on how environment stimuli affect the establishment of root system architecture.