‘库尔勒香梨’果实发育过程中石细胞形成与细胞凋亡的关系研究  

Study on the relationship between the stone cell formation and apoptosis during the fruit development of ’Kuerlexiangli’ pear

作　　者：艾沙江·买买提[1] 张校立[1] 梅闯[1] 马凯[1] 闫鹏[1] 韩立群[1] 王继勋[1] Aisajan·Mamat;ZHANG Xiaoli;MEI Chuang;MAKai;YAN Peng;HAN Liqun;WANG Jixun(Institute of Horticultural Crops,Xinjiang Academy of Agricultural Sciences/Scientific Observing and Experimental Station of Pomology(Xinjiang),Ministry of Agriculture,Urumqi 830091,Xinjiang,China)

机构地区：[1]新疆农业科学院园艺作物研究所·农业部新疆地区果树科学观测试验站

出　　处：《果树学报》2020年第1期59-67,共9页Journal of Fruit Science

基　　金：国家自然科学基金(31760565);自治区公益性科研院所基本科研业务经费(KY2017075)

摘　　要：【目的】探讨‘库尔勒香梨’果实发育过程中石细胞的形成与细胞凋亡(PCD)之间可能存在的关系,为调控‘库尔勒香梨’果实石细胞含量、改善果实品质提供科学依据。【方法】以15 a(年)生‘库尔勒香梨’(Pyrus sinkiangensis Yü)为试材,通过显微观察和含量测定,研究果实发育过程中石细胞的形成规律和活性氧(ROS)的积累特性,同时用3种不同细胞凋亡的检测方法检测了果肉细胞细胞核浓缩情况、DNA的片段化现象。【结果】‘库尔勒香梨’果实发育过程中,石细胞含量呈先上升后下降趋势,最大值出现在花后50 d,为20.22%。随后,石细胞含量随着果实的膨大迅速下降;到花后120 d,石细胞含量降低到3.37%。石细胞的染色结果表明,花后10~20 d大部分石细胞还处于松散聚集的初始阶段,一部分石细胞团已经成型,但未达到最大体积,花后30 d石细胞开始大量聚簇,形成石细胞团,至花后50 d石细胞数量和大小趋于稳定。ROS含量变化与果实中石细胞含量变化相一致,果实发育前期积累多,后期逐渐减少。细胞凋亡检测显示,香梨果实发育过程中确实出现细胞凋亡现象。TUNEL、DAPI和Hoechst染色都表明,果实发育早期阶段(花后10~40 d)是‘库尔勒香梨’果肉细胞发生凋亡的关键时期,花后75 d开始,PCD荧光信号较弱或基本检测不到凋亡信号。【结论】‘库尔勒香梨’果实石细胞形成的关键时期是花后10~50 d。PCD发生时期和ROS积累时期与石细胞形成时期基本重叠。【Objective】‘Kuerlexiangli’pear(Pyrus sinkiangensis Yü) is a native species of the Xinjiang Autonomous Region in China. At present, high stone cell content, which leads to rough skin, is one of the most important factors decreasing fruit quality. Stone cells are a type of sclerenchyma cell formed by the secondary thickening of cell walls followed by the deposition of lignin on the primary walls of parenchyma cells. While we understand a great deal of the genes involved in lignin synthesis and deposition, we know surprisingly little concerning the transition from the primary to the secondary cell wall synthesis. Secondary walls are formed between the plasma membrane and the primary walls in specialized cells after the cessation of cell expansion. They are mainly composed of cellulose, hemicelluloses and lignin, the proportions of which may vary in different cell types and plant species. Therefore, the development of stone cells cannot be fully explained by the deposition of lignin in the secondary cell walls. All the biosynthesis genes for cellulose, hemicelluloses and lignin need to be turned on as well as the genes responsible for the supply of nucleotide sugars, phenylpropanoid pathway precursors, methyl and acetyl donors and many other secondary wall biosynthetic pathway precursors need to be up-regulated to construct secondary walls. After their biosynthesis, lignin monomers must be transported to the cell wall where they are oxidized for polymerization, reactive oxygen species(ROS) plays a key role in this process. Meanwhile, ROS is the main trigger of programmed cell death(PCD). PCD,also called apoptosis, is an active behavior, genetically controlled either by so-called death receptors or intrinsic signals that direct the cell to eliminate itself during development and in response to pathogens or environmental insults. Therefore, it is speculated that the formation of stone cells is essentially the process of apoptosis. Some parenchymal cells in pear fruit stop growing and differentiate early at cel

关 键 词：‘库尔勒香梨’ 果实发育 石细胞 细胞凋亡 活性氧 

分 类 号：S661.2[农业科学—果树学]