【作者】 刘洋；

【导师】 杜国栋； 汪晓谦；

【作者基本信息】 沈阳农业大学 ， 果树学， 2018， 硕士

【摘要】 秋子梨(Pyrus ussuriensis Maxim.)在我国寒冷地区的果树生产中占有很重要的地位,它具有果实香气浓郁,抗寒力强等特点。但近年来由于品种退化,导致萼片宿存严重,石细胞增多等,严重影响了果实品质,降低其市场竞争力。本研究以秋子梨为试材,分别从不同方面对果实中木质素代谢进行研究,分析其木质素合成中间代谢产物变化和基因表达规律,为秋子梨果实石细胞的有效调控奠定基础。主要内容如下:1.果实发育过程中,尖把梨的单果重和横纵径高于南果梨,尖把梨果实木质素含量始终高于南果梨。发育前期,二者木质素含量均较高,随着果实的生长发育,其木质素含量逐渐降低,花后130 d,南果梨果实木质素含量仅为尖把梨的19.3%。果实纵切面染色区域主要集中在果核周围,其染色程度与木质素含量变化相一致。果实酚类物质分析发现,南果梨果实中木质素中间产物含量低于尖把梨,而类黄酮物质总量高于尖把梨,与木质素的积累显著相关。两个品种的木质素合成基因表达具有时空的特异性,综合来看,LAC、C3H和PAL基因与两个品种中木质素含量相关性较高,可能是导致其木质素积累差异的关键基因。2.果实发育过程中,南果梨脱萼果和宿萼果的生长情况基本一致,脱萼果果实木质素含量始终低于宿萼果,花后130 d,脱萼果和宿萼果果实木质素含量分别为1.6%和3.8%。从木质素含量动态变化表明,二者木质素合成主要集中在果实发育的前期,且存在明显差异。从酚类成分含量的动态分析结果来看,脱萼果果实中木质素中间产物含量低于宿萼果,而类黄酮物质含量高于宿萼果,与木质素的积累显著相关。对木质素合成途径相关基因进行表达分析,发现C3H和4CL基因可能是影响南果梨脱萼果和宿萼果木质素合成差异的关键基因。3.南果梨果实发育过程中,石细胞含量与木质素含量变化趋势相一致,果实发育前期,含量较高,后期逐渐下降。对果实木质素和ROS进行组织化学定位,ROS水平与果实木质素含量在时间空间上存在同步性。ROS及ROS代谢相关酶NADPH氧化酶、SOD和POD活性水平与果实木质素含量变化存在密切联系。通过对RBOH基因家族表达水平分析,部分RBOH基因可能与果实木质素含量变化存在相关性。本试验从不同角度对秋子梨果实木质素代谢的生理生化特性及基因表达差异进行研究,为如何调控秋子梨果实石细胞提供重要的理论依据。更多还原

【Abstract】 Pyrus ussuri ensis Maxim.occupies an important position in the production of fruit trees in cold regions of China.It has the characteristics of rich fruit aroma and strong cold resistance.However,due to the degeneration of varieties in recent years,the occurrence of severe calyx,the increase of persistent calyx pear,and the increase of stone cells have seriously affected the quality of fruits and reduced their market competitiveness.In this study,Pyrus ussuriensis Maxim.was used as the main test material to study the lignin in fru its from different aspects to understand the changes of intermediate metabolites and gene expression patterns of lignin synthesis,which laid the foundation for effective regulation of Pyrus ussuriensis Maxim.stone cells.The main contents are as follows:During the development of fruit,the fruit weight,transverse diameter and vertival diameter of Jianba pear were higher than that of Nanguo pear.the lignin content of Jianba pear was always higher than that of Nanguo pear.In the early stage of development,both lignin contents were high.With the growth and development of fruits,their lignin content gradually decreased.130 days after full bloom,the lignin content of Nanguo pear was only 19.3% of the Jianba pear.The area of vertival section dyeing of fruit was mainly concentrated around the nucleus,and the degree of dyeing was consistent with the change of lignin content.Analys is of fruit phenolic compounds found that the content of lignin intermediates in Nanguo pear fruit was lower than that of Jianba pear,and the total amount of flavonoids was higher than that of Jianba pear,which was significantly related to the accumulation of lignin.The lignin synthesis gene expression of the two varieties has temporal and spatial specificity.Overall,LAC,C3 H and PAL genes are highly related to the lignin content in the two varieties,and may be the key genes that cause differences in their lignin accumulation.With the development of fruit,the fruit growth of dropping calyx pear and persistent calyx pear was similar.The fruit lignin content in dropping calyx pear was always lower than that in the persistent calyx pear.130 days after full bloom,the fruit lignin content of dropping calyx pear and persistent calyx pear was 1.6% and 3.8%,respectively.From the dynamic analysis results of the content of phenolic components,the content of lignin intermediate product in the dropping calyx pear was lower than that of the persistent calyx pear,the content of flavonoids was higher than that of the persistent calyx pear and was signif icantly related to the accumulation of lignin.Analysis of genes related to lignin synthesis pathways revealed that C3 H and 4CL genes may be the key genes affecting the differences in lignin synthesis between dropping calyx pear and persistent calyx pear.In the process of Nanguo pear fruit development,the stone cell content was consistent with the change trend of lignin content,and the fruit had a higher content in the early stage of fruit development and gradually decreased in the later per iod.The fruit lignin and ROS were histochemically localized,and the ROS level and the fruit lignin content were synchronized in time and space.The study found that there is a close relationship between the levels of NADP H oxidas e,SOD and POD activities and the content of stone cells in ROS and ROS metabolism related enzymes.In the study,the POD,SOD and NOX activities in fruits were consistent with changes in lignin content in fruits.During the early per iod of fruit development,their activities were relatively high.With the development of fruits,their activity was gradually reduced and maintained at a stable level.By analyzing the expression level of RBOH gene,there was a correlation between RBOH gene and fruit lignin content.This experiment studied the physiological and biochemical characteristics and gene expression differences of lignin metabolism in Pyrus ussuriensis Maxim.fruit from different angles,and provided an important theoretical basis for how to regulate the stone cells of Pyrus ussuriensis Maxim.fruit.更多还原