不同季节遮荫对青钱柳生长和主要次生代谢物积累的影响

青钱柳是近年来开发利用的我国特有药食同源珍稀植物，其叶中含有的活性次生代谢物对人体健康具有促进作用。探索光照条件和收获季节等环境因子对主要次生代谢物积累的影响以及生长与次生代谢物积累间关系，有助于优化药用青钱柳人工林栽培条件。该文采用遮荫处理，研究不同遮荫水平下6—11月青钱柳叶中黄酮类和三萜类化合物积累、苗高和地径生长的变化，在此基础上分析青钱柳次生代谢与生长间的关系。结果表明:中度遮荫促进了青钱柳苗的高生长，但随遮荫程度加大，地径生长不断下降。黄酮类化合物、总三萜和青钱柳甙Ⅰ的积累受到遮荫处理的抑制，而青钱柳酸B和阿江榄仁酸的含量在遮荫条件下明显高于自然光下。在自然光下，黄酮类化合物的含量在8月和10月明显高于其他季节，呈“双峰型”变化模式。但遮荫处理推迟了黄酮类物质积累的高峰。遮荫处理并未影响三萜类化合物的季节变化模式，总三萜和三萜单体的含量在不同遮荫水平下均在9月达到最大，呈“单峰型”变化模式。相关性分析结果表明，总三萜和阿江榄仁酸的积累与青钱柳生长间存在显著负相关关系。由此可见，遮荫不仅显著降低了黄酮类化合物的积累，而且推迟了其积累高峰；而三萜的季节变异模式未受遮荫影响，但不同三萜单体对光照的响应存在差异。 

Effects of shading and season on growth and accumulation of major secondary metabolites in Cyclocarya paliurus

Cyclocarya paliurus is a multiple function plant, and has been traditionally used for drug formulations or ingredients of functional foods in China. Previous studies have shown that the leaves of C. paliurus contain a large number of physiological active compounds, such as flavonoids and triterpenoids, which were known to carry important physiological activity in humans. Understanding the variation patterns in secondary metabolites accumulation, and the relationship between secondary metabolism and growth along the environmental gradients can provide meaningful information for the standardized cultivation of medicinal artificial forest of C. paliurus. Shading treatment was used for studying the effects of shading treatments and sampling time on growth and accumulation of important secondary metabolites in C. paliurus from June to November. Furthermore, the relationship between secondary metabolism and growth of C. paliurus was analyzed. Our results indicated that tree height growth of C. paliurus was improved under one-layer shading, while basal diameter growth was significantly decreased under shading conditions. Accumulation of flavonoids, total triterpenoid, and cyclocarioside Ⅰ were significantly restrained by shading treatments. However, accumulation of other two individual triterpenoids cyclocaric acid B and arjunolic acid was improved by shading treatments. Under natural light condition, flavonoid contents in August and October were significant higher than other seasons, and showed a bimodal variation pattern. While, the fastigium of flavonoid accumulation in leaves of C. paliurus was delayed by shading treatment. Furthermore, under different shading conditions, the highest contents of total and individual triterpenoids were detected in September, and showed an unimodal variation pattern. A significant negative relationship between growth and accumulation of total triterpenoid and arjunolic acid was found through correlation analysis.