Abstract:

The morphological responses and adaptation of oneyear old seedlings of Castanea henryi、Fagus Longiptiolata and Cycloblanopsis glauca to different light environments were studied in 100%, 56% and 32% of full sun light. The results showed that seedlings of C. henryi 、F. longiptiolataand C. glauca had different morphological responses to different light environments, and the change extent of growth indexes with light environment showed C. henryi＞ F. longiptiolata ＞ C. glauca. Seedling height, basal diameter and root length of the three tree species seedlings all had a decreasing trend with the decrement of light intensity. The leaf number, leaf length, leaf width and mean leaf area of C. henryi seedlings gradually increased with light intensity. The leaf number of F. longiptiolata and C. glauca seedlings had a decreasing trend while leaf length, leaf width and mean leaf area of F. longiptiolata and C. glauca seedlings all showed an obviously increasing trend with dimming light. Leaf area of C. henryi seedlings was the largest in full sunlight but that of F. longiptiolata and C. glauca seedlings were the smallest in 56% full sunlight intensity. Specific leaf area and leaf area ratio of the three tree species seedlings all had an increasing trend with reducing light intensity. The increment was significant in both C. henryi and F. longiptiolata, however not in C. glauca. There were obvious differences in biomass accumulation among the three species seedlings to different light conditions. Biomass of C. henryiand F. longiptiolata declined markedly with decreasing light intensity, and the change range of C. henryi was obviously higher than that of F. longiptiolata,while C. glauca had no obvious difference in biomass. The biomass allocation pattern over the organs of the three species seedlings had no obvious change in different light condition. Quality index can reflect the coordination and balance of each part of tree species seedling, and it can provide scientific basis for judging regeneration seedling transplantation survival rate. Quality index of the three species seedlings in the full sunlight were all the highest. C. henryiand F. longiptiolata in full sunlight had significantly higher quality index than that in shading treatment, while there was no significant difference of quality index in C. glauca seedlings over the different light intensities.

Key words: Castanea henryi, Fagus longiptiolata, Cycloblanopsis glauca, seedlings, light environment, morphological responses, ecological adaptation