Effect of diferent levels of N fertilization on Yield and Amount of Alkaloids vincristine and vinblastine in Periwinkle (Cataharanthus roseus L.G.Don)

Periwinkle (Catharanthus roseus (L.) G. Don)، a medicinal plant، which economiclly is highly valued because of its anti-cancer lalkaloids of vincristine and vinblastine. Since the availability of nitrogen (N) is expected to play an important role in the biosynthesis and accumulation of alkaloids in plants، the effect of N fertilization on the content of alkaloids of periwinkle was studied. the four levels of 0، 100، 150، 200 kg/ha N fertilization in a bulok completely randomized design with three replications. N fertilization significantly increased the content of alkaloids in leaves. This study showed that by increasing N fertilization dry weight increased. The highest level of alkaloid vincristine was in the 0 kg/ha of N fertilization and the highest level alkaloid vinblastine was in the 200 kg/ha of N fertilization.