柑橘果实化渣性研究

Mastication of Citrus Fruit

作者: 专业:果树学 导师:刘永忠 年度:2010 学位:硕士  院校: 华中农业大学

Keywords

Citrus, Mastication, Cell wall metabolism, Gene expression

        柑橘果肉化渣性是衡量柑橘品质的一个重要指标,将直接影响果实的商品性。柑橘果实的化渣性与果肉中膳食纤维的成分有一定联系,与细胞壁物质代谢有关。由于品种退化及栽培管理不当等原因,一些原本性状良好的柑橘品种出现化渣性能下降的现象,因此,有必要对柑橘果实化渣性进行研究。本研究对奉节及南丰地区柑橘化渣性能表现出差异的六个品种在生长过程中果肉细胞壁(果胶、纤维素、半纤维素和木质素等)代谢的动态变化从生理、生化和分子三个层面进行研究,以期找到影响柑橘果肉化渣性的关键因素及时期。主要结果如下:1、对重庆奉节地区两个脐橙品种,‘奉节72-1脐橙’(FJ72-1,Citrus sinensisOsbeck cv.Fengjie 72-1)和‘奉节晚橙’(FJWC, C. sinensis Osbeck cv.Fengjiewancheng)细胞壁相关物质代谢进行研究.结果表明:化渣性较差的奉节晚橙中原果胶、纤维素和半纤维素含量在成熟期均高于奉节72-1脐橙,水溶性果胶含量则相反,而两个品种中木质素含量差别不大,且两个品种在发育过程中细胞壁物质变化趋势比较相似。PG,PME和Cel花后230d的基因表达量在‘奉节晚橙’中相对‘奉节72-1脐橙’较低。2、对江西南丰地区四个南丰蜜橘品种,普通南丰蜜橘(PN,Putongnanfengmiju).南丰蜜橘优系(YN,Nanfengmijuyouxi)‘蜜广’(MG,Miguang)和‘火广’(HG,Huoguang)细胞壁相关物质代谢进行测定.结果表明:尽管四个品种在化渣性能方面出现差异,果胶、纤维素、半纤维素和木质素含量在整个生长过程中变化趋势却比较相似,且采收期时细胞壁物质含量却无明显差异;四个品种PG酶活在花后150d达到最高,随后略有下降,PAL基因表达量在花后40d达最高。
    Fruit mastication is an important index to evaluate citrus fruit quality, which directly influences the commodity quality of fruit. Dietary fiber properties in the pulp are related with mastication of citrus fruit, which may refer to cell wall metabolism. Nowadays, several citrus varieties with excellent characters got inferior mastication, due to the deterioration of variety and inappropriate cultivation and management. Thus, it is necessary to research into the citrus mastication to solve the problem.The study was conducted to gain insight into key factors and periods that impact citrus fruit texture by determining the dynamic changes of cell wall metabolism (pectin, cellulose, hemicellulose and lignin) from aspects of physiology, biochemistry and molecular throughout development of six varieties with different mastications. The main results were as follows:Cell wall metabolism of’FJ72-1’(FJ72-1, Citrus sinensis Osbeck cv. Fengjie 72-1) and’FJWC’(FJWC, C. sinensis Osbeck cv. Fengjiewancheng) in Fengjie, Chongqing area were measured. Contents of protopectin, cellulose and hemicellulose in ’Fengjiewancheng’with inferior mastication were obviously higher than in’Fengjie 72-1 novel orange’at mature stages and water soluble pectin content was the opposite. Lignin content of the two varieties had almost no difference. And changing patterns of cell wall materials of the two varieties were similar. Lower expression level of PG, PME and Cel at harvest time might also be associated with the inferior-mastication character.Cell wall metabolism of’PN’(PN, C. sinensis Osbeck cv. Putongnanfengmiju)、’YN’ (YN, C. sinensis Osbeck cv. Nanfengmijuyouxi)、’MG’(MG, C. sinensis Osbeck cv. Miguang) and’HG’(HG, C. sinensis Osbeck cv. Huoguang) in Nanfeng, Jiangxi area were measured. Although the four varieties showed differences in mastication, pectin, cellulose, hemicellulose and lignin contents were similar during fruit development and cell wall substances didn’t exhibit any obvious differences at harvest time. PG enzyme activities of the four varieties reached highest peak at 150d, and then decreased slightly.PAL gene expression of the four varieties was highest at 40d.
        

柑橘果实化渣性研究

摘要6-7
Abstract7-8
缩略词表9-10
1.前言10-17
    1.1 课题的提出10-11
    1.2 前人研究进展11-16
        1.2.1 果实质地的研究概况11-14
            1.2.1.1 柑橘果肉的汁胞粒化12
            1.2.1.2 桃果肉的溶质性12-13
            1.2.1.3 梨果肉的咀嚼性13
            1.2.1.4 柑橘果肉的化渣性13-14
        1.2.2 与果实化渣性相关的细胞壁物质代谢研究进展14-16
            1.2.2.1 细胞壁物质的组成14
            1.2.2.2 果胶代谢14-15
            1.2.2.3 纤维素代谢15
            1.2.2.4 木质素代谢15-16
    1.3 本研究的目的与内容16-17
2 材料与方法17-23
    2.1 实验材料17-18
    2.2 实验方法18-23
        2.2.1 样品制备18
        2.2.2 果实总的可溶性固形物及可滴定酸含量的测定18
        2.2.3 果实细胞壁主要成分的测定18-19
            2.2.3.1 果胶含量的测定18
            2.2.3.2 纤维素、半纤维素和木质素含量的测定18-19
        2.2.4 果实细胞壁主要水解酶活性的测定19-20
            2.2.4.1 酶的提取19
            2.2.4.2 多聚半乳糖醛酸酶活性的测定19
            2.2.4.3 果胶甲酯酶活性的测定19-20
            2.2.4.4 纤维素酶活性的测定20
        2.2.5 细胞壁水解酶相应基因的实时定量分析20-22
            2.2.5.1 RNA的提取20-21
            2.2.5.2 反转录合成cDNA第一链21
            2.2.5.3 几种酶基因的Real-time PCR表达分析21-22
        2.2.6 数据处理22-23
3 结果与分析23-38
    3.1 奉节脐橙成熟过程中可溶性固形物、可滴定酸和质地相关组分变化动态23-30
        3.1.1 奉节脐橙可溶性固形物和可滴定酸变化动态23-24
        3.1.2 奉节脐橙果肉果胶的动态变化24-25
        3.1.3 奉节脐橙果肉纤维素、半纤维素的动态变化25-26
        3.1.4 奉节脐橙果肉木质素的动态变化26-27
        3.1.5 奉节脐橙果肉细胞壁相关酶活性的变化27-28
        3.1.6 奉节脐橙果肉细胞壁相关酶基因表达的差异28-30
    3.2 南丰蜜橘成熟过程中可溶性固形物、可滴定酸和质地相关组分变化动态30-38
        3.2.1 南丰蜜橘可溶性固形物、可滴定酸的变化动态30-31
        3.2.2 南丰蜜橘果肉果胶的动态变化31-33
        3.2.3 南丰蜜橘果肉纤维素、半纤维素的动态变化33
        3.2.4 南丰蜜橘果肉木质素的动态变化33-34
        3.2.5 南丰蜜橘果肉细胞壁相关酶活性的变化34-35
        3.2.6 南丰蜜橘果肉细胞壁相关酶基因表达的差异35-38
4 讨论38-41
    4.1 奉节脐橙生长过程中细胞壁代谢研究38-39
    4.2 南丰蜜橘生长过程中细胞壁代谢研究39
    4.3 影响柑橘果实化渣性的因素39-41
参考文献41-49
硕士期间发表论文49-50
致谢50
        


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