The impacts of increased nitrate supply on Catharanthus roseus growth and alkaloid accumulations under ultraviolet-B stress

摘要

It has been reported that nitrate availability was able to modify the detrimental effects induced by excess ultraviolet-B (UV-B) radiation on plants. In this study, the medical plant Catharanthus roseus was subjected to UV-B stress and altered levels of nitrate nutrition to investigate their influence in a sole or combined way on growth and alkaloid productions. Our results showed that the UV-B stress obviously inhibited growth and led to damages of oxidative stress and lipid peroxidation. The simultaneous supply of higher nitrate nutrition could largely alleviate the inhibitory effects and damage symptom under the UV-B stress in C. roseus. Meanwhile, the UV-B-absorbing compounds as well as three alkaloids, vinblastine, vindoline, and catharanthine, were observed to have a remarkable elevation. These compounds were considered to serve as protectants of UV-B radiation. It was concluded that an increased nitrogen (N) supply could not only alleviate the inhibitory effect of UV-B stress on plant growth, but a...