基于衍生化GC-MS法分析不同栽培基质对铁皮石斛代谢的影响

栽培基质是影响铁皮石斛生长的主要因素之一,本研究拟选用松树皮(PB)、椰糠(CC)和松树皮:椰糠(PC,1:1)的复合基质栽培铁皮石斛,基于代谢组学思路探究栽培基质对铁皮石斛茎生长代谢的影响.通过环刀法测定3种基质的物理性质,利用苯酚-硫酸比色法测定铁皮石斛茎的多糖含量,采用硅烷化衍生化法结合气相色谱-质谱法检测铁皮石...

Effect on Metabolites of Dendrobium officinale by Different Cultivation Substrates Based on Derivative GC-MS Method

Cultivation substrate is one of the main factors affecting the growth of Dendrobium officinale. In this study, the substrates of pine bark (PB), coconut coir (CC) and the mixture of pine bark∶coconut coir in 1∶1 ratio (PC) were used to plant D. officinale. On the basis of metabolomics, the effects of the properties of the three cultivation substrates on the metabolism of D. officinale stems were investigated. Cutting ring method was used to determine the physical properties of the three cultivation substrates, phenol-sulphuric acid method was used to detect the content of polysaccharides, and gas chromatography mass spectrometry (GC-MS) method was performed to detect the primary metabolites. The results indicated that the aeration porosity and water holding capacity in the group of coconut coir and complex substrate were higher than that of the substrate of pine bark, the content of polysaccharides were ranked as coconut coir > complex substrate > pine bark. Principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) for multivariate statistical analysis of 42 identified metabolites showed that the samples cultivated in different substrates clustered into one group, and the separation between groups was obvious, indicating the metabolites of the samples from different groups existed a significant difference. Combined with fold change (FC), the VIP values calculated based on the OPLS-DA model were used to screen the metabolites with significant difference. When the conditions (VIP>1 and FC≥2 or FC≤0.5) were set, there were a total of fourteen, eleven and five metabolites, with significant differences in content across groups being screened in the comparison of pine bark and complex substrate, pine bark and coconut coir, complex substrate and coconut coir, respectively. A large part of metabolites with significant difference in the group of coconut coir and complex substrate performed a lower accumulation in the pine bark group. The results gained by combined analysis between the physical properties of the three cultivation substrates and the metabolites with significant difference revealed that if the cultivation substrate had the weaker aeration and capacity of water supply, there would be a stronger expression in crassulacean acid metabolism (CAM). Thus, C₃ pathway would become weaker, and carbohydrates accumulate less. In other words, the substrate with the properties of high aeration porosity and good water holding capacity was beneficial to the accumulation of carbohydrate in D. officinale. Therefore, this study could provide data and theoretical guidance for the cultivation of D. officinale.