Influence of Different Levels of N P K on Photosynthetic Character and Activeness in Ginkgo Leaves

Based on Hongland solution, ten solutions of different N, P, K ratios were prepared for primary study on the influence of N, P, K on some photosynthetic parameters in sand-cultured Ginkgo leaves. The results were as follows: Net photosynthetic rate, stomatal conductance, water use efficiency, carboxilation rate, apparent quantum effriciency, photosynthetic ability and maxium electric transportation rate in Ginkgo leaves all went up as the concention of N, P, K in solution increased, but went down as the concentration of N, P, K increased to excess. Lack or excess of supply of N, P, K led to higher ratio of photorespiration to mass photosynthetic rate in Ginkgo leaves.