Influence Of Nitrogen Levels On The Growth And Camptothecin Content Of Camptotheca Acuminata Seedlings

Camptotheca acuminate, a tree species native to China, has gained great attention for its secondary metabolites camptothecin which has remarkable anticancer and antiretrovirus activities. A field experiment was carried out to investigate the effect of different nitrogen on growth of C. acuminata seedlings. The effects of nitrogen nutrition on growth and camptothecin content of C. acuminate seedlings were studied. Determined the changes of photosynthesis index, nutrient elements, metabolic enzymes activity in leaves of C. acuminata seedlings. The relationship between various indicators and nitrogen levels was discussed. Provide reference data and technical support for the rational fertilization of C. acuminate. The main results are as follows.(1) With the increase of nitrogen level, content of height, ground diameter, root length and leaf number of C. acuminata showed first increased then decreased trend, and in 30 g per plant was highest. The root number decreased initially and increased, and in 30 g per plant was lowest. Throughout the growth process, the indicators of control always remained low.(2) With the increase of nitrogen level, photosynthesis index of C. acuminata leaves showed first increased then decreased trend, and in 30 g per plant was highest. Chlorophyll content and soluble protein content along with the increased nitrogen levels showed a gradual upward trend, and in 50 g per plant was highest.(3) With the increase of nitrogen level, nitrogen content of C. acuminata leaves showed a gradual upward trend, and in 50 g per plant was highest. Phosphorus content along with the increased nitrogen levels showed first increased then decreased trend, and in 30 g per plant was highest. Potassium content with increasing nitrogen level was gradually decreased, and in 50 g per plant was lowest.(4) NR activity and GS activity in leaves and roots of C. acuminata increase with the increase of nitrogen level, GS activity in 50 g per plant and NR activity in 40 g per plant was highest. Excess nitrogen 50 g per plant could inhibit the activity of NR, and the NR activity and GS activity of leaves was much higher than that of roots.(5) CPT concentration in C. acuminata leaves increased first and then decreased with the increase of nitrogen levels, and in 20 g per plant was highest. Camptothecin yield per plant in 30 g treatment was the highest, the control(N0) was the lowest.Integrated indicators, considered the right amount of nitrogen levels 30 g per plant will improve the C. acuminata growth. Promote the accumulation of nutrient elements in the leaf. Improving the activity of metabolic enzymes, and then contributing to the biosynthesis of camptothecin.