基于矿质元素和氮稳定同位素比值的金钗石斛栽培模式判别研究

Discrimination of cultivation modes of Dendrobium nobile based on content of mineral elements and ratios of nitrogen stable isotopes

该研究探讨矿质元素含量和氮同位素比值对金钗石斛栽培模式判别的可行性,以期为金钗石斛栽培模式的判别提供理论支撑。测定大棚栽培、附树栽培、附石栽培3种栽培方式下金钗石斛及其栽培基质样品中11种矿质元素氮(N)、钾(K)、钙(Ca)、磷(P)、镁(Mg)、钠(Na)、铁(Fe)、铜(Cu)、锌(Zn)、锰(Mn)、硼(B)含量和氮同位素比值。结合方差分析、主成分分析、逐步判别分析对不同栽培类型样品进行分类。结果表明,除Zn元素外,氮同位素比值与其余元素含量在不同栽培类型金钗石斛间均存在显著差异(P<0.05);相关性分析结果表明,金钗石斛中的氮同位素比值、矿质元素含量及药效成分含量与对应栽培基质中的氮同位素比值和矿质元素含量存在不同程度的相关。主成分分析可初步对金钗石斛样品归类,但部分样品存在交叉现象。通过逐步判别分析,筛选出δ15N、K、Cu、P、Na、Ca等6个指标可用于建立金钗石斛栽培方式的判别模型,经回代检验、交叉检验及外部验证的整体正确判别率均为100%。因此,氮同位素比值和矿质元素指纹结合多元统计分析可有效判别金钗石斛的栽培类型,研究结果为金钗石斛的栽培类型及产地识别提供了一种新的方法,也为金钗石斛的品质评价和质量控制提供实验依据。

This study explored the feasibility of mineral element content and ratios of nitrogen isotopes to discriminate the cultivation mode of Dendrobium nobile in order to provide theoretical support for the discrimination of the cultivation mode of D. nobile. The content of 11 mineral elements(N, K, Ca, P, Mg, Na, Fe, Cu, Zn, Mn, and B) and nitrogen isotope ratios in D. nobile and its substrate samples in three cultivation methods(greenhouse cultivation, tree-attached cultivation, and stone-attached cultivation) were determined. According to the analysis of variance, principal component analysis, and stepwise discriminant analysis, the samples of different cultivation types were classified. The results showed that the nitrogen isotope ratios and the content of elements except for Zn were significantly different among different cultivation types of D. nobile(P<0.05). The results of correlation analysis showed that the nitrogen isotope ratios, mineral element content, and effective component content in D. nobile were correlated with the nitrogen isotope ratio and mineral element content in the corresponding substrate samples to varying degrees. Principal component analysis can preliminarily classify the samples of D. nobile, but some samples overlapped. Through stepwise discriminant analysis, six indicators, including δ15N, K, Cu, P, Na, and Ca, were screened out, which could be used to establish the discriminant model of D. nobile cultivation methods, and the overall correct discrimination rates after back-substitution test, cross-check, and external validation were all 100%. Therefore, nitrogen isotope ratios and mineral element fingerprints combined with multivariate statistical analysis could effectively discriminate the cultivation types of D. nobile. The results of this study provide a new method for the identification of the cultivation type and production area of D. nobile and an experimental basis for the quality evaluation and quality control of D. nobile.