不同生长期黄芪无机元素动态特征分析

目的:探究不同生长期黄芪中Mg、Ca、V、Mn、Fe、Co、Ni、Cu、Zn、Ba这10种无机元素的含量差异与动态积累特征，从无机元素层面对黄芪适宜采收期的确定提供帮助。方法:收集不同生长期黄芪样品，采用电感耦合等离子体质谱法测定其元素含量，并结合单因素方差分析、主成分分析（PCA）、正偏最小二乘判别分析（OPLS-DA）和相关性分析方法分析黄芪药用部位生长过程中无机元素的变化及积累规律。结果:不同生长期黄芪10种元素含量差异较大，Mg、Ca、V、Mn、Fe、Ni、Cu、Co元素均在10月份时含量达到最大值，Ba在6月份时含量达到最大值，8月为上述元素含量最小值时的生长期，Zn元素在9月的含量显著高于其他生长期，7月时含量显著低于其他生长期（P<0.05），10种元素含量均为先降后升的动态变化趋势。相关性分析结果表明:V与Ca、Fe；Ni与Ba元素之间均存在极显著性相关关系（P<0.01），主成分分析综合得分结果表明10月份黄芪样品得分排名第一，正偏最小二乘判别分析表明Zn、Ni、Cu、V四种元素为鉴别不同生长期黄芪的主要特征元素。结论:黄芪中无机元素含量与其生长期密切相关，无机元素可以作为黄芪采收期确定的指标之一。综合分析，10月中下旬为黄芪药材的最佳采收期。

Dynamic Characteristics of Inorganic Elements in Astragalus membranaceus at Different Growth Stages

Objective: To explore the dynamic accumulation characteristics of 10 inorganic elements including Mg, Ca, V, Mn, Fe, Co, Ni, Cu, Zn and Ba in Astragalus membranaceus at different growth stages, and determine the optimal harvesting period. Methods: Collected Astragalus membranaceus form different growth stages and determined its element contents by inductively coupled plasma mass spectrometry(ICP-MS), then analyzed its changes and accumulation rule by one-way ANOVA, principal component analysis(PCA), orthogonal projections to latent structures discriminant analysis(OPLS-DA) and correlation analysis. Results: The contents of 10 elements of Astragalus membranaceus at different growth stages were significantly different. The contents of Mg, Ca, V, Mn, Fe, Ni, Cu and Co reached the peak in October, and Ba reached the peak in June. The contents of above element were the lowest in August. The content of Zn in September was significantly higher and in July was significantly lower than that in other growing seasons (P<0.05). The contents of 10 elements all showed a dynamic trend of decreasing first and then increasing. Correlation analysis showed that there was a very significant correlations between V and Ca, Fe, Ni and Ba (P<0.01). The results of principal component analysis showed that the score of Astragalus in October ranked first. The orthogonal projections to latent structures discriminant analysis showed that Zn, Ni, Cu and V were the main characteristic elements for identifying Astragalus membranaceus in different growth stages. Conclusion: The content of inorganic elements in Astragalus membranaceus was closely related to its growing stage and inorganic elements could be used as one of the indexes to determine the harvest period of Astragalus membranaceus. Comprehensive analysis showed that middle October was the best harvest time for Astragalus membranaceus.