GROWTH, MORPHOLOGY AND BIOMASS ALLOCATION IN RESPONSE TO LIGHT GRADIENT IN FIVE SUBTROPICAL EVERGREEN BROADLEAVED TREE SEEDLINGS

We compared seedling growth, leaf morphology and biomass allocation of five widely distributed, evergreen species (Elaeocarpus sylvestris, Illicium henryi, Quercus phillyraeoides, Gardenia jasminoides and Ardisia crenata) under varying controlled light conditions using artificial shade houses. Regardless of species, higher height growth rate was observed at intermediate light levels (33–52% sunlight). Diameter growth rate, however, increased with increasing light level. Morphological variables (mean leaf area, total leaf area per plant, specific leaf area and leaf area ratio) were significantly affected by light, with greater variation occurring in deep shade treatment (6% sunlight). Total biomass increased with light levels for E. sylvestris, Q. phillyraeoides and G. jasminoides but larger biomass was found at intermediate light levels for I. henryi and A. crenata. Biomass allocation patterns displayed small variations in the five species. Although the five species differ in their growth strategy across a light gradient, their large plasticity allows them to grow well under a wide range of light environments. As a whole, E. sylvestris, Q. phillyraeoides and G. jasminoides showed their best growth above 52% sunlight. Optimal light condition for I. henryi and A. crenata were from 33 to 52% sunlight. Our findings support the underplanting of these five evergreen species in order to enrich the biodiversity of subtropical plantation ecosystems.