Aboveground Biomass Component Plasticity and Allocation Variations of Bamboo (Pleioblastus amarus) of Different Regions

Abstract

Bamboo is one of the most important forest resources, widely distributed throughout subtropical and tropical regions. Many studies have focused on bamboo functional trait variation under different environmental conditions. However, the functional feature response of bamboo components to regional and climatic factors and associated coupling effects are less known. This study analyzed phenotypic plasticity and biomass accumulation and allocation processes in aboveground Pleioblastus amarus components (i.e., the culm, branch, and leaf) with principal component analysis (PCA) and partial least squares structural equation modeling (PLS-SEM) in three regions of China. Consequently, obvious regional differences were observed in phenotypic plasticity, biomass accumulation, and allocation processes. With decreasing latitude and increasing longitude, the internode length was longer for larger and rounder bamboo and the culm wall was thinner at a lower relative total height. Moreover, the number and width of crowns became greater, thicker, and longer. With increasing latitude, branch and leaf biomass decreased significantly, while biomass allocation to bamboo branches and leaves first decreased before increasing. And with increasing longitude, culm and total biomass reduced significantly along with culm biomass allocation, while total branch and leaf biomass allocation gradually decreased. Clearly, climatic factors, such as maximum temperature and mean annual temperature, directly affected the phenotypic plasticity of P. amarus and its associative biomass accumulation. Meanwhile, soil factors (i.e., soil available phosphorus, capillary porosity, field water holding capacity, and total nitrogen content) caused significant variation in phenotypic plasticity, indirectly affecting plant biomass accumulation and allocation processes. Collectively, these initial findings indicate that low-latitude and high-longitude stands promoted greater morphogenesis and more efficient biomass accumulation and allocation in aboveground P. amarus components, exhibiting superior morpho-plasticity and higher stand productivity. This study clarified regional differences in P. amarus morphological phenotypic plasticity and biomass accumulation and allocation. It is expected that the results can aid in provenance selection and the directional cultivation of high-yield bamboo stands.