栽培甜菜助细胞退化进程的超微结构观察  

Ultrastructure of Synergid in Its Degenerative Process in Sugar Beet(Beta vulgaris)

作　　者：李伟[1,2] 申家恒[2] 郭德栋[3] 

机构地区：[1]东北林业大学盐碱地生物资源环境研究中心/东北油田盐碱植被恢复与重建教育部重点实验室,黑龙江哈尔滨150040 [2]哈尔滨师范大学生命科学与技术学院/植物生物学黑龙江省高校重点实验室,黑龙江哈尔滨150025 [3]黑龙江大学生命科学院,黑龙江哈尔滨150070

出　　处：《作物学报》2013年第12期2220-2227,共8页Acta Agronomica Sinica

基　　金：国家自然科学基金项目(30470114);植物生物学黑龙江省高校重点实验室(哈尔滨师范大学)开放基金项目资助

摘　　要：应用透射电镜技术研究栽培甜菜(Beta vulgaris)助细胞退化进程的超微结构特征,以丰富被子植物生殖生物学资料。结果表明:花蕾时期,2个助细胞相似,珠孔端具发达的丝状器,合点端无壁,极性明显,细胞器种类多,数量大,呈现较强代谢活性;随后,一个助细胞的核质和胞质的电子密度显著高于另一个助细胞,液泡膜消失,线粒体、质体膜与核膜不清晰,细胞出现退化迹象,但内质网和高尔基体丰富,分泌活动旺盛;待花蕾刚开放(授粉前),此助细胞完全退化。另一个助细胞(宿存助细胞)内的细胞器逐渐增多,且功能状态趋于活跃,表现为核糖体、线粒体、质体等数量增加;线粒体内嵴丰富,可见DNA纤丝;质体形态多样,片层明显,内含淀粉粒。至卵细胞受精前(授粉后约13 h),宿存助细胞代谢达到最活跃状态;至合子合点端建成蜂窝状细胞壁且胚乳游离核形成后,宿存助细胞开始退化;至合子后期,此细胞退化完全,丝状器消失。上述结果表明,栽培甜菜助细胞的退化与授粉和花粉管生长无关;宿存助细胞做为传递细胞,为胚囊的发育吸收并转输营养。Anexperiment was conducted by using TEM to study the degenerative process of synergid in sugar beet, so as to provide more information for reproductive biology of angiosperm. The results were as follows： two synergids were similar in flower bud stage with large number of organelles. Both of them had developed filiform apparatus （FA） at micropyle end and lacked cell wall at chalazal end, showing obvious polarity. Then electron density in one synergid increased. On the other hand, vacuole membrane disappeared, membrane of mitochondrium, plastid and nuclear became illegible, which suggested cell degeneration began. But endoplasmic reticulum and Golgi bodies were still active. Complete degeneration of this synergid occurred before pollination. Number of organelles including mitochondrium, plastids and ribosomes gradually increased in the other synergid （persistent synergid）. Mitochondria contained many tubular cristae and obvious DNA fibril. Plastids were irregular in shape and usually contained starch gains and thylakoid membranes. The metabolism of persistent synergid gradually enhanced until fertilization （about 13 h after pollination）. It began to degenerate when zygote had alveolate cell wall at the chalazal end and endosperm occurred, while complete degeneration and disappearance of FA took place at late stage of zygote. The results indicated that degeneration of one synergid in sugar beet must be triggered by other stimulation than pollination and pollen tube growth. As a transfer cell, persistent synergid may absorb and transport nutrition for the development of embryo sac.

关 键 词：栽培甜菜 助细胞 退化进程 超微结构 

分 类 号：S566.3[农业科学—作物学]