Photosynthetic Characteristics of Blumea balsamifera under the Condition of Shading Treatments
【摘要】：[Objective] To study the photosynthetic characteristics of Blumea balsamifera (Linn.) DC under the condition of shading treatments. [Method] Under pot culture, B. balsamifera leaves with 1 (7%-10%), 2 (15%-20%), and 4 (30%-40%) layers of shading were studied. Li-6400 portable photosynthetic analyzer was used to detect and compare the photosynthesis daily change and the light response curve of B. balsamifera leaves. Photosynthetic characteristics of photosynthesis to the light intensity of B. balsamifera were studied. [Result] Daily change of photosynthetic rate (Pn) in one layer shading treatment showed a double-peak curve. The peak values were at 10:30 and 13:30 and the curve bottom was at 12:30, showing significant phenomenon of "midday depression". As for the 2- and 4-layer shading treatments, photosynthesis was relatively weak and was fluctuated around 0 in the whole daytime. Photosynthetic rates of B. balsamifera in three shading treatments were in the order of 1-layer shading 2-layer shading 4-layer shading. The responses of photosynthetic rate (Pn) were in the order of 1-layer shading 2-layer shading 4-layer shading. [Conclusion] The photosynthetic rate in 1-layer shading treatment was significantly higher than those in other two treatments, showing obviously high photosynthetic efficiency. Leaves had different photoresponse characteristics to different photosynthetic active radiations.