Abstract: Litsea coreana Levl. var. sinensis has developed four heteromorphic leaf types to adapt to the local environment. This study investigated functional traits of four heteromorphic leaf types through morphological, anatomical, photosynthetic, and activity compounds to elucidate their niche differentiation within a single tree. Lanceolate (La) type had the largest leaf length (LL = 8.43 cm), leaf shape index (LSI = 2.85), leaf perimeter (LP = 18.51 cm), but low palisade tissue thickness (TPTT), light saturation point (L_SP), and light compensation point (L_CP), suited for varied positions and mild, humid climates. Ovoid (Ov) and orbiculate (Or) types had highest leaf thickness (LT = 0.2 mm) and high TPTT (66.93 and 63.97 μm), high chlorophyll (0.695 and 0.696 mg/g), high net photosynthetic rate (P_Nmax = 8.140 and 6.618 μmol·m^-2·s^-1), high Total flavonoid content (TFC = 45.216 and 47.704 mg/g), adapting top and edge canopy positions amid high temperatures and sun. Oblanceolate (Ob) type had largest SLA (117.22 cm²/g) and high dark respiration rate (R_d), but low TPTT and chlorophyll, adapting for shade in the lower canopy. As the LL increased the LSI progressively increased. As the TPTT, the P/S (Palisade/Spongy) gradually increases. As the L_SP, the P_Nmax gradually increases. Three principal components were extracted with a cumulative contribution of 75.196%, of which the Ov type had the highest composite principal component score. Our findings provide evidence that the presence of heteromorphic leaf types facilitates the utilization of different microhabitat by L. coreana Levl. var. sinensis.

Key words: Heteromorphic leaves, Leaf structure, Photosynthesis, Litsea coreana Levl. var. sinensis, Plant response