增强UV-B辐射及氮水平对长春花生长和生理代谢的影响

地表UV-B 辐射增强和氮沉降增加目前已成为影响植物生长的重要生态因子。本文以药用植物长春花（Catharanthus roseus）为材料，研究UV-B辐射和氮供应增加对长春花生长、生理及长春碱含量的协同效应。研究结果表明，紫外辐射增加对长春花生长和生物量积累具有显著的抑制作用。同时外源增加氮供应能明显缓解紫外辐射引起的生长抑制效应。紫外辐射引起的叶片膜脂过氧化胁迫导致了长春花叶片丙二醛含量显著增加，但同时增加氮供应能显著降低丙二醛水平。增强UV-B辐射处理显著促进长春花叶片UV-B吸收化合物合成积累，并随氮供应增加其含量进一步增加；氮供应增加和UV-B辐射增强共同作用时，长春花叶片中长春碱的含量较其单独作用时均显著增加。上述结果表明，增加氮供应不但可以缓解紫外辐射引起的生长抑制和生理伤害，同时对长春花叶片中生物碱的合成积累具有协同促进效应，其原因可能是增强UV-B辐射能促使长春花利用更多的氮源合成积累长春碱。

The Effects of Supplementary UV-B Radiation and Nitrogen Levels on the Growth and Physiological Metabolism of Catharanthus roseus

The increased UV-B radiation and nitrogen deposition have become two important environmental factors affecting plant growth. Here, a medical plant Catharanthus roseus was subjected to altered UV-B and nitrogen level to study their influence in a sole or combined way on growth and vinblastine production. Our results showed that the UV-B exerted an obviously adverse effect on plant growth and biomass accumulation. The UV-B stress also led to physiological damages, for instance, the elevated MDA content. The increased supply with nitrogen nutrition could largely alleviate the inhibitory effects and damage symptom induced by UV-B stress. The UV-B absorbing compounds were enhanced remarkably by the supplementary UV-B radiation, and it was increased further when the nitrogen nutrition were supplied. The vinblastine content was increased markedly in the supplementary UV-B radiation, and which were increased further when the nitrogen supply increased. It was concluded that an increased nitrogen supply could not only alleviate the inhibitory effect of UV stress on plant growth, but enhance vinblastine accumulation in plants. We proposed that enrichment of nitrogen nutrition provide more N source for alkaloid synthesis induced by UV-B radiation, eventually resulting in increased alkaloid content.