【作者】 聂敬全；

【导师】 蔡永萍；

【作者基本信息】 安徽农业大学 ， 遗传学， 2009， 硕士

【摘要】 砀山酥梨(Pyrus bretschneideri cv.)为我国梨出口的主要品种之一,但是近年来由于品种退化或是管理不善的原因,石细胞含量增加,肉质变粗,口感多渣,严重影响了砀山酥梨的品质和经济价值。因此,本实验以砀山酥梨为材料,系统研究梨果实石细胞发育的规律,了解石细胞发育与果实薄壁细胞发育的关系;探讨木质素代谢对石细胞形成的影响,并对梨果实中木质素代谢的途径进行初步研究。旨在探讨石细胞发育的机理,为调控梨果实石细胞形成和含量、了解石细胞发育与木质素代谢的关系提供理论依据,及为研究梨果实木质素代谢途径提供技术方法。主要研究结果如下:1、梨石细胞先由果肉细胞壁不均匀加厚,进而形成厚壁细胞。石细胞由薄壁细胞次生壁加厚形成的,石细胞细胞壁加厚的部分被番红染成红色,且呈不均匀加厚,加厚最先在细胞角隅处发生,然后扩展到整个细胞壁。2、石细胞形成始于花后15天,此后一周内形成大量石细胞;花后23天,石细胞聚簇,石细胞团大量出现,石细胞团直径增大;花后67天,石细胞团直径最大,此时薄壁细胞以长条状和椭球状两种方式膨大。梨果实发育过程中,石细胞含量先上升后下降,花后51天,石细胞含量达18.95%,以后石细胞含量下降。石细胞由薄壁细胞发育而来,是薄壁细胞分化的一个方向,另一个方向是膨大成熟。石细胞含量的下降是由于果实生长和薄壁细胞膨大引起的相对下降。3、石细胞的形成受木质素合成的影响,梨果实发育过程中,石细胞含量与木质素含量呈显著正相关,相关系数R2=0.9847。石细胞形成的时期,梨果实中苯丙氨酸解氨酶、过氧化物酶、多酚氧化酶活性相对较高,石细胞形成结束后,梨果实中PAL、POD、PPO活性相对较低。PAL、POD、PPO影响梨果实石细胞的形成和木质素的合成,梨果实中石细胞的分布与薄壁细胞分裂、膨大的程度有关。4、采用高效液相测定方法,在梨发育过程中分离检测到肉桂酸和对香豆酸,初步确定木质素的合成可能是经过对香豆酸进入木质素合成特异途径的。5、砀山酥梨、贡梨、丰水梨、库尔勒香梨、苹果梨五种不同基因型成熟梨果实中,石细胞含量与木质素含量呈正相关,梨果实中石细胞含量高的部位木质素含量也高,基因型梨果实石细胞的含量与PAL、POD、PPO活性之间没有相关性。更多还原

【Abstract】 Pyrus bretschneideri cv. is one of the export pears in China. However, it affected the quality of Pyrus bretschneideri cv. that stone cell content increased, taste more than java and flesh became coarse as a result of variety degradation or mismanagement in recent years. Therefore, this experiment studied the development of stone cells, understanding the relationship between the development of stone cell and parenchyma; explore the metabolism of lignin on the forming of stone cells; and preliminary study the path of lignin metabolism in Pyrus bretschneideri cv.. Designed to investigate the mechanism of stone cells, in order to provide theoretical basis for controlling the forming of stone cells, understanding the relationship between the forming of stone cells and lignin metabolism, and provide the ways for studying lignin metabolism farther of pear. Key findings are as follows.1 Unequal thickness of fruit parenchyma cells’wall forms thick wall cell, thick wall cells developed to stone cell through cell wall re-thickness in pear. Stone cell formed through thickening of secondary wall of parenchyma. Part of unequal thickness wall was dyed red by Safranine. The thickness began at took place in the cell, and than extended to the entire cell wall.2 The forming of stone cell mostly started at DPA15 and it commenced largely within a week. The stone cells gathered and emerged at DPA23 and the diameter of stone cell group enlarges. The max diameter of stone cell group came forth at 67DPA. At the same time, the Parenchyma cells grew and enlarged with two different methods, strip and ellipsoid. The content of stone cell increased firstly, and then descended during pear fruit development. The max content of stone cell came forth at 51DPA(18.95%). Some of the parenchyma could develop into stone cells, the others would expand and maturate. The content of stone cell was determined the forming of stone cell and the expansion of parenchyma cells during fruit development.3 Synthesis of lignin affected the forming of stone cell. The content of stone cell and lignin was significant correlation during development of pear fruit, correlation coefficient R2=0.9847. The activity of ammonia-lyase, peroxidase, polyphenol oxidase are all relatively high during the forming of stone cell in pear fruit. And then the activity of PAL, POD, PPO were relatively low. PAL, POD, PPO affected the forming of stone cell and synthesis of lignin in pear. But the distribution of stone cell is related to the degree of division as expanding of parenchyma..4 The experiment detected the cinnamic acid and P-coumalic acid in pear fruit of development. Cinnamic acid is the product of Benzene propane metabolic and starting substance of metabolic pathway-specific of lignin. P-coumaric is the important branch of pathway-specific of lignin and translated from cinnmic acid. Therefore, the synthesis of lignin may be through p-cumaric acid into the lignin-specific pathway in pear fruit.5 The content of stone cell and lignin was positive correlation in five different genotype pear fruit- Pyrus bretschneideri cv, Gong pear, Fung pear, Korla fragrant pear and apple-pear. The parts of high stone cell content have high lignin content also. It is unclear of the relationship between the content of stone cell and the activity of PAL, POD, PPO in different genotypes pear.更多还原