[Objective] The study was conducted to investigate the effects of shading treatments on growth of Asimina triloba(L)Dunal seedlings and provided the theoretical basis for seedling production.[Method]70 day-old A.triloba seedlings had similar stem diameter and plant height and good growth vigour were taken as tested materials in 2005.4 light gradient treatments which were the natural light with 100% light intensity,one-layer,two-layer and three-layer black shading network with the light transmittance rate of 50%,25% and 12.5% were set up to study the effects of different shading treatments on growth of A.triloba.[Result]With the shading treatments of one-layer and two-layer net,the plants of A.triloba seedlings grew rapidly.As the intensity of illumination decreased,the contents of chlorophyll a(Chl.a),chlorophyll b(Chl.b)and total chlorophyll increased at first and then reduced.At the same time the chlorophyll a/b value became smaller.Under natural light,the plants tended to consume more water and the soil temperature at 15:00 p.m was higher.There was a smaller difference among various treatments.[Conclusion]The suitable shading treatment to the growth of A.triloba seedlings was under the light transmittance rate of 50% and height and stem diameter of trees increased fast.Chlorophyll a(Chl.a),chlorophyll b(Chl.b)content in leaves of A.triloba seedlings were highest comparing with those in other conditions.
