遮荫处理对泡泡树幼苗生长的影响

泡泡树[Asimina triloba（L．）Dunal]是美国本土生长的最大的乔木果树，在我国无自然分布。选择泡泡树幼苗适宜的光照强度对于加快该树种的推广、成功繁殖苗木极为重要。

Effects of Shading Treatments on Growth of Asimina triloba(L.)Dunal Seedlings

[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 soed 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 trailsmittance 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 consunle more water and the soil temperature at 15:00 p.m wag higher.There was a smaller difference among various treatments.[Conclusion]The suitable shading treatment to the growth of A.triloba seedlings wag under the light transmittancn rate of 50% and height and stem diameter of trees increased fast. Chlorophyll a(Chi.a),chlorophyll b(Chl.b)content in leaves of A. triloba seedlings were highest comparing with those in other conditions.