栽培环境对铁皮石斛生长与代谢成分的影响

为明确栽培环境对铁皮石斛的生长及代谢成分的影响,对铁皮石斛C13品系在岩壁附生、梨树附生和设施盆栽3种栽培环境下进行形态特征、显微结构、多糖和浸出物含量的观察与分析。结果表明,生长环境显著地影响铁皮石斛的生长,在农艺性状上,岩壁附生和梨树附生的铁皮石斛叶片稀少、颜色由绿变紫红、伸展角度减小,茎秆多呈紫色、较粗壮,茎长分别为3.4,4.0 cm,普遍比设施盆栽(7.5 cm)短,且根系特别发达;在显微结构上,野外生长的铁皮石斛与设施栽培比均表现出叶片增厚、上表皮厚度增加、下表皮表皮毛丛生、气孔小而密,根被细胞、外皮层、内皮层的细胞壁均偏厚,且根被、外皮层、内皮层、髓部的细胞小且排列紧密,但栽培环境没有产生特异性的组织结构,主要是结构参数大小和数量的变化,说明铁皮石斛具有很好的环境适应能力;此外,生长环境显著地影响铁皮石斛多糖和醇溶性浸出物等代谢成分的积累,岩壁附生铁皮石斛多糖和醇溶性浸出物含量最高,质量分数分别达37.34%,11.66%,梨树附生次之,质量分数分别为33.90%,9.62%,均高于设施盆栽;通过HPLC分析,岩壁附生铁皮石斛中醇溶性浸出物成分比另外2种栽培模式更加复杂,说岩壁附生栽培环境更有利于铁皮石斛次生代谢产物的合成和积累。

Effects of cultivation environments on Dendrobium catenatum

The study was aimed to clarify the effect of three cultivation environments on the growth and metabolism of Dendrobium catenatum C13 group. There were three different cultivation conditions including rock epiphytic cultivation, pear epiphytic cultivation and pot cultivation. Morphological characteristics and agronomic characters of D. catenatum were observed and measured. Microstructure, contents of polysaccharide and alcohol-soluble extracts were measured by paraffin section method, phenol-sulfuric acid method and hot-dip method, respectively. The result showed that the cultivation environment significantly affected the growth of D. catenatum, the leaves of D. catenatum that cultivated on the rock and pear were sparse and small, the stems were short and purple and the root system was developed. Compare with potted cultivation, D. catenatum from rock epiphytic cultivation and pear epiphytic cultivation showed the following characteristics in the microstructure:the upper epidermis became thicker, the epidermal hair in the epidermis became denser, stomatal showed smaller and denser, the cell wall of exodermis, endoderm and medulla became thicker, the cell of velamen, exodermis, endoderm and medulla were smaller and arranged more closely, but the cultivation environment did not produce specific tissue structure, mainly changed in the structural parameters of size and quantity. The growth environments also influenced contents of polysaccharides and alcohol-soluble extracts. The dontents of polysaccharides and alcohol-soluble extracts in D. catenatum from rock epiphytic were the highest, reached 37.34% and 11.66%, the second was pear epiphytic, both higher than pot cultivation, alcohol-soluble extracts contents in D. catenatum from rock epiphytic are more complex, which shows that rock epiphytic is conducive to the accumulation of secondary metabolites in D. catenatum.