Effects Of Nitrogen Nutrition On Growth And Camptothecin Concentration In Leaves Of Camptotheca Acuminate Seedlings

Camptothecin (CPT) is an important anti-tumor natural compound containing nitrogen. It was mainly extracted from Camptotheca acuminata. The effects of nitrogen levels and nitrogen forms on the growth and the camptothecin concentration in leaves of C. acuminata seedlings were studied. We also determined the changes of nitrate reductase (NR) activities, glutamine synthetase (GS) activities and chlorophyll concentration, nitrogen concentration in leaves of C. acuminata seedlings under different of nitrogen levels and forms to examine the relationship between the above mentioned parameters of nitrogen assimilation and CPT concentration in leaves as affected by nitrogen levels and forms. The results show under below:The growth speed of C. acuminata seedlings increased with increasing the nitrogen levels. There was a significantly logarithmic relationship between growth speed of plants and the nitrogen levels. The growth speed of C. acuminata seedlings was higher when plants received NO3- than when they received two other forms, that is NH4+ and NO3-", and there was no evidently difference between that of the latter two nitrogenous forms.The concentration of chlorophyll and nitrogen, the activity of NR and GS in leaves of C. acuminata seedlings increased with increasing the levels of nitrogen nutritious. At all the nitrogen forms treatments, the sequences of the concentration of chlorophyll, concentration of nitrogen and the activity of NR in leaves were NCO3>NO3-+NH4+>NH4+, whereas the sequence of GS activity was NO3-