Morphological and physiological response of Acer catalpifolium Rehd. Seedlings to water and light stresses

Abstract As a critically endangered species, Acer catalpifolium Rehd is included in the wild plants with extremely small populations (WPESP) rescue and protection plan. Understanding of the responses of A. catalpifolium to various resource and environment conditions could help identify potentially suitable environments for its conservation. We used an orthogonal experiment design to evaluate the growth, morphological and physiological responses of A. catalpifolium and a widespread same-genus species A. mono to diverse water and light stresses. The results showed that a 75% soil water holding capacity and moderate shade are suitable for seedling growth. Drought and shade had significant negative effects on plant growth, biomass accumulation, and physiological functions. Lowering specific leaf areas (SLA), increasing root biomass allocation, and pigment content were the main strategies for enhancing water and light capturing abilities to acclimate to the limited ambient resources. The general plasticity index of plant growth, biomass, and physiological characteristics were higher in A. mono than in A. catalpifolium . We also explored the suitable light and water requirements for A. catalpifolium seedling growth. Our research would be useful for population regeneration and could aid in biodiversity conservation of Acer species.