Comparison of five broad-leaved seedlings' physiological characteristics in natural secondary forest of eastern Liaoning

Artificially controlled light illumination on five major broad-leaved seedlings (2 years) was tested in the mountains area of Liaoning,in order to study their physiological characteristics. The results showed that alls species have very feeble photosynthesis under lower light environment (relative illumination 10%),with maxmium net photosynthetic rate (P n) at 4～6 μmol CO 2·m -2·s -1.There was a little significant difference among species. The photosynthesis changes with the illumination and showed significant difference between species. The P n of Tilia amurensis, F.mandshurica, and F.rhynchophylla increase slowly while that of Pherodendron amurense and Quercus mongolica increase quickly. At the same time, the light complementation point (LCP) and dark expiration rate of T. amurensis, F. mandshurica, and F. rhynchophylla are lower respectively and can accumulate substances using lower light. The LCP of P. amurense and Q. mongolica, however, are higher and have great photosynthetic potential using facula under crown. The changes of light have an effect on accumulation of seedlings' dry biomass. The biomass of T. amurensis, F. mandshurica, and F. rhynchophylla under full light environment is 2.91～5.44 times higher than that under feeble light (RI 10%).Biomass of P. amurense and Q.mongolica under full light environment is 16.62～19.42 times higher than that under feeble light (10%).