Effects of rocky desertification on growth and biomass accumulation and distribution of terminal twigs in Viburnum chinshanense Graebn.

Karst rocky desertification is a serious geological disaster in southwestern China. Viburnum chinshanense Graebn. shrubs were selected to study how growth of its terminal twigs responded to different degrees of rocky desertification by assessing its biomass accumulation and allocation and morphological plasticity. Results showed that in the rocky desertification area, twig biomass accumulation was significantly restrained, and the degree of restraint increased with the degree of rocky desertification. Compared with leaf and stem biomass, the decrease in flower biomass was minimal. Compared with non-rocky desertification, the morphological growth indexes (leaf number, leaf area, specific leaf area, stem length, and stem diameter) of V. chinshanense significantly decreased, and the inhibition of rocky desertification on stem length was greater than that of stem diameter, whereas leaf area was the most inhibited. Leaf biomass and stem biomass ratios in the slight and moderate rocky desertification habitats increased as an adaptation to such habitats. However, in three of the habitats with different degrees of rocky desertification, the reproductive investment of V. chinshanense increased by increasing the flower biomass ratio to ensure reproductive capacity and population continuity. V. chinshanense uses strategies to reduce the investment of vegetative organs, such as leaves and stems, to adapt to harsh habitats and maintain ecosystem structure and stability at the maximum degree.