Low phenotypic plasticity of plants of monsoon tropical forest to light and their adaptation to scarce resources
Light is a limiting factor for plants growth and development in the tropical forest understory. At the same time, its characteristic feature is a highly heterogeneous distribution, to which the plants have to adapt. Adaptation is possible by means of phenotypic plasticity. We have assessed the phenotypic plasticity level of leaf parameters to the light factor in 17 species of undergrowth and understory layers. The majority of changes in leaf parameters in changing light conditions were determined by species differences (64.0 % on average). The studied species were divided into six groups according to their plasticity level. For each group, different leaf characteristics played a key role in light adaptation. Consequently, each of the studied species had its own means of light adaptation, and the adaptation strategy in the undergrowth setting was aimed at adaptation to a narrow range of light conditions. This was reflected in the low level of plasticity (the mean RDPI value was 0.12), which allowed species to occupy narrow ecological niches and ensured effective coexistence of plants in the context of limited resources.