细茎石斛花朵挥发性成分分析

Volatile components in flowers of Dendrobium moniliforme

为了探究细茎石斛花朵释放的挥发性成分特点,该研究利用固相微萃取(SPME)法结合GC-MS技术,检测了花色为黄绿的细茎石斛花朵不同花期、不同部位的挥发性成分和相对含量,还比较了黄绿色、白色和白色带淡紫色等三种花色的挥发性成分。结果表明:花色黄绿的细茎石斛花朵挥发性化合物成分总计为59种,其中盛花期最复杂(含有41种),这些成分归属于烯类、芳香族化合物、含氮化合物、酯类、醇类和醛酮类。在不同花期检测到的挥发性成分中,(1R)-(+)-α蒎烯相对含量始终最高,保持在27%以上;始花期和盛花期释放且相对含量较高的成分有顺-芳樟醇氧化物、β-水芹烯、柠檬烯、罗勒烯、(1S-cis)-4,7-二甲基-1-(1-甲基乙基)-1,2,3,5,6,8α-六氢萘和乙酸芳樟酯,相对含量均高于5%;衣兰烯于花蕾期相对含量最高,衰落期消失。这8种化合物可能是细茎石斛花香释放的主要香气成分或特征成分。在花色黄绿的细茎石斛盛开期的两个开花部位中,花瓣的挥发性成分有27种,蕊柱17种,其中烯类物质分别占74.16%和79.06%,花瓣可能是细茎石斛主要的释香部位。三个花色的细茎石斛盛花期挥发性化合物均在40种左右,既有成分的差异又有含量的差别,其中有25种为共同含有,三个花色均是(1R)-(+)-α蒎烯相对含量最高,含量在27%左右。这表明烯类物质是影响细茎石斛花香的重要化合物,不仅对细茎石斛产品开发提供了参考,而且还为其花香基因工程育种奠定了基础。

In order to understand the volatiles in flowers of Dendrobium moniliforme,the constituents and relative contents in different florescences and flower parts of the yellow-green flower color of D.moniliforme were determined by solid phase microextraction(SPME)and gas chromatography coupled with mass spectrometry(GC-MS),and the volatile components of three kinds colors of D.moniliforme were also compared by analyzing the constituents and relative contents determined in flowering stage.The results showed that there were 59 volatile compounds identified at four flowering stages of the yellow-green flower color of D.moniliforme,and the flowering stage was the most complicated stage because there were 41 volatile compounds.These compounds belongs to alkenes,aromatic,nitrogenous compound,esters,alcohols,alkanes,aldehydes and ketones.The relative contents of 1R-α-pinene was more than 27%,which was the highest among all compounds at four flowering stages;During the first flowering stage and flowering stage,there were another six compounds including cis-linaloloxide,β-phellandrene,limonene,3,7-dimethytl-1,3,7-octatriene,(1S-cis)-4,7-dimethyl-1-(1-methylethyl)-naphthalene,1,2,3,5,6,8α-hexahydro and 3,7-dimethyl-1,6-octadien-3-ol-acetate,and their relative contents was the highest;The relative contents of ylangene was more than 5%during bud stage,and disappeared during declining stage.Thus,the eight compounds were the major volatile components or the characteristic constituents for D.moniliforme.There were 27 components identified in petals and 17 in gynandrium.In petals and gynandrium,the relative content of alkenes compounds was the highest,74.16%and 79.06%,respectively.And the petals were probably the most important part that could influence the volatile releasing.There were about 40 components identified in the flowering stage of three colors of D.moniliforme,differently.And there were 25 common constituents existed in three colors of D.moniliforme.Alkenes was the most important compounds for D.moniliforme.This plays an important role for aromatic cultivar breeding and essential product development of D.moniliforme.