ON SHADE TOLERANCE OF 741 POPLAR
“741杨”扦插苗耐阴性的研究

Using black shading net, we set up four light conditions (e. g. 100%, 24. 5%,7. 5% and 2. 5% of full light) under which the cuttings of poplar grown. The effects of light intensity on leaf growth, leaf anatomic structure, chlorophyll content, ligtphotosynthesis curve, growth of newly produced sprouts and biomass were investigated.The results show that 741 poplar is a light tree species. Biomass and other parameters were all higher under 100% light than the other light conditions. The plants had a strong compensation at the level of 24. 5% of full light. The single leaf area, growth rate of newly produced sprouts, chlorophyll content and pettole length were larger, but total biomass was smaller, under full light than 34. 4% of full light conditions. Under 7. 5% of full light, the plants reached their limitation of shade tolerance. The plants were not able to survive for long term under 2. 5% of full light conditions.