Some Important Characteristics Of Mineral Nutrition Of Camptotheca Acuminata Decne

Camptotheca acuminata Decne is rich in camptothecin (CPT) , which is known as an anticancer material for mankind. In the present study, some nutritional characteristics of this plant species were investigated in order to improve their production technology. The obtained results revealed that among the nutritionally essential mineral elements studied, the contents of nitrogen (N) and potassium (K) in the leaves derived from nutritional branches remarkably decreased in spring, and the contents of phosphorus (P), Mg (magnesium), Mn (manganese) and copper (Cu) changed gently in the growing season. The contents of Iron (Fe) and zinc (Zn) showed a change of fluctuation characteristics. Calcium (Ca) content increased obviously with the development of leaves. For above nine nutritional elements, their contents were stable relatively in August. Therefore, the nutritional diagnosis could be determined during this period.The results also showed that the content of N,P,K, reducing sugar,total water soluble sugar, starch and the ratio of C/N in the leaves of flourishing-fruit-period were higher than those of first-fruit-period and non-fruit-period. There was no obvious difference of CPT contents between in flourishing-fruit-period and first-fruit-period with ranged from 0.65g.kg-1DW to 0.70g.kg-1DW.The results indicated that the contents of N, P, K, carbohydrate and C/N ratio in the leaves of high-yield-tree were higher than those of low-yield-tree. Furthermore, the contents of P and starch in the leaves of old-fruit-branch were higher than those of watershoot at the stage of physiological differentiation, but were lower than those of watershoot at the stage of morphological differentiation. The contents of P, K total water soluble sugar and starch in the leaves of old-fruit-branch were higher than those of watershoot during the flower-bud differentiation period. In contrary, N content in the leaves of old-fruit-branch was lower than that of watershoot.Also, the obtained results displayed that the growing condition of the tree was affected by various forms and rate of nitrogen applied. With increasing the ratio of NH₄⁺-N, the height, trunk diameter and yield of this plant increased. The higher of the ratio of NH₄⁺-N in nutritional liquids, the more of N content, and the lower content of K in roots and leaves. For P content, the amount in the leaves was higher than that in the roots. The content of total water soluble sugar increased in the roots and leaves, but starch decreased with increasing the ratio of NH₄⁺-N in the present study. Photosynthetic rate (Pn) treated with both NO₃^--N and NH₄⁺-N was higher than that of with only...