枸杞果实生长发育过程中细胞壁多糖及其降解酶活性变化研究

Study on the Changes of Cell Wall Polysaccharide and Their Degrading Enzyme Activities during the Development of Lycium barbarum Fruit

为进一步探究枸杞多糖代谢规律,以不同生长时期的枸杞果实为研究对象,用透射电镜观察细胞壁微观结构,通过化学法提取细胞壁多糖并测定含量及其降解酶活性,使用显微共聚拉曼光谱法分析不同生长时期枸杞果实细胞壁多糖成分的变化规律,并对其细胞壁多糖含量与降解酶活性进行了相关性分析。结果表明:枸杞果实细胞壁结构变化主要发生在28~35 d,细胞壁明显变薄,果胶降解,细胞壁结构逐渐崩毁。细胞壁物质(CWM)含量先增加后降低,水溶性果胶(WSP)含量显著增加(P<0.05),碳酸钠可溶性果胶(SSP)和半纤维素含量先增加后降低。多聚半乳糖醛酸酶(PG)、β-半乳糖苷酶(β-Gal)和纤维素酶(Cx)活性升高,果胶甲酯酶(PME)和β-氨基己糖苷酶(β-Hex)活性先降低后升高。相关性分析结果表明,在枸杞果实生长发育过程中细胞壁多糖含量与细胞壁降解酶活性显著相关(P<0.05)。随着枸杞果实的发育和成熟,其细胞壁微观结构随降解酶活性的变化呈细胞壁结构崩毁、细胞壁多糖降解的变化趋势。研究结果对提高枸杞果实的加工品质、制定适合的贮藏策略具有理论和实践意义。

To further explore the metabolism of Lycium barbarum polysaccharides,the cell wall microstructure of Lycium barbarum fruits in different growth periods was observed by transmission electron microscopy,and the cell wall polysaccharide content and its degrading enzyme activity were extracted by chemical method.The changes of polysaccharide components in cell wall of Lycium barbarum fruits in different growth periods were analyzed by microcopolymer Raman spectroscopy.The correlation between the content of polysaccharide in cell wall and the activity of degrading enzyme was analyzed.The results showed that the changes of cell wall structure mainly occurred during 28~35 d,with the cell wall becoming significantly thinner,pectin degrading,and the cell wall structure gradually collapsing.Cell wall material(CWM)content increased first and then decreased,and water-soluble pectin(WSP)content increased significantly(P<0.05).Sodium carbonate-soluble pectin(SSP)and Hemicellulose contents increased firstly and then decreased.The activity of polygalacturonase(PG),β-galactosidase(β-Gal)and cellulase(Cx)increased,and the activity of pectin methylesterase(pectin methylesterase)increased.The activity of PME andβ-hexosaminidase(β-Hex)decreased at first and then increased.The results of correlation analysis showed that the polysaccharide content of cell wall was significantly correlated with the activity of cell wall degrading enzyme during the growth and development of Lycium barbarum fruit(P<0.05).With the development and maturation of Lycium barbarum fruit,the microstructure of cell wall showed a trend of cell wall collapse and polysaccharide degradation with the change of degrading enzyme activity.The results have theoretical and practical significance to improve the processing quality of Lycium barbarum fruit and formulate suitable storage strategies.