Biology and ecophysiology of macrophytes

Abstract

Aquatic environments are subjected to high physical and chemical variations (water level, turbidity, temperature, light, salinity, nutrients). Hydrophytes respond to these variations with great morphological and physiological plasticity, which allows them to adapt to heterogeneous environments, whether spatial or temporal. Assemblages of biological traits confer strategies of regeneration and colonisation, depending on the constraints or disruptions. Thus we show 1) that vegetative reproduction is especially prevalent among macrophytes, therefore facilitating the recolonization after disturbance, 2) Plasticity of biological traits is almost a rule among macrophytes, and is demonstrated in many species in response to hydraulic and trophic constraints and to disturbances by floods. Plants respond to variations in the trophic level by phosphorus accumulation, which depends on species, season and conditions of mineralization environment. Enzymatic activities are modified in the plant: this is the case of nitrate-reductase inhibited by ammonia nitrogen.