Developmental pathway of somatic embryogenesis in Picea abies as revealed by time-lapse tracking
Developmental pathway of somatic embryogenesis in Picea abies as revealed by time-lapse tracking
复制标题
DOI：
10.1093/jexbot/51.343.249
复制
发表时间：
2000-02-01
影响因子：
6.9
通讯作者：
von Arnold, S
中科院分区：
文献类型：
--
作者：
Filonova, LH;Bozhkov, PV;von Arnold, S
几种针叶树物种可以通过体细胞胚胎发生繁殖。这是无性繁殖的一种有用的方法，但它也可以用于研究针叶树胚胎发育是如何调节的。然而，在针叶树中，体细胞胚和合子胚发育的相似程度尚不清楚，因为对体细胞胚的起源和发育的研究很少。建立了一种时间推移跟踪技术，从挪威云杉胚性悬浮培养物中分离出2000多个单细胞和少细胞聚集体。喀斯特。）并嵌在琼脂糖薄层中。实验已经表明，体细胞胚从原胚发生块发育而来，所述原胚发生块通过一系列的三个特征性阶段（阶段I、II和III）转分化成体细胞胚，所述三个特征性阶段通过细胞组织和细胞数量来区分。不同类型的结构的显微镜检查显示，原胚发生群众的特点是高度克隆间的形状和细胞组成的变化。与此相反，体细胞胚是形态保守的结构，具有明显的原皮层样细胞层以及胚性管细胞和胚柄。单克隆抗体JIM 13所识别的阿拉伯半乳聚糖蛋白表位染色的缺乏被证明是区分原胚发生团块与体细胞胚的有效标记。在原胚性团块中的绝大多数细胞表达该表位，而在早期体细胞胚中没有细胞表达该表位。促进细胞增殖的条件（即外源生长素和细胞分裂素的存在），抑制体细胞胚的形成;相反，通过具有致密细胞质的胚性细胞的不均等分裂的阶段I proembryogenic群众的连续增殖是占主导地位的过程。一旦体细胞胚形成，它们进一步发育为成熟形式需要脱落酸，并与合子胚共享共同的组织分化模式。虽然体细胞胚发育的最早阶段相比proembryogenesis不能被表征，随后的发育过程中发生的早期和晚期合子胚密切相关。建立了欧洲云杉体细胞胚胎发生途径的模型。
Several coniferous species can be propagated via somatic embryogenesis. This is a useful method for clonal propagation, but it can also be used for studying how embryo development is regulated in conifers. However, in conifers it is not known to what extent somatic and zygotic embryos develop similarly, because there has been little research on the origin and development of somatic embryos. A time-lapse tracking technique has been set up, and the development of more than 2000 single cells and few-celled aggregates isolated from embryogenic suspension cultures of Norway spruce (Picea abies L. Karst.) and embedded in thin layers of agarose has been traced. Experiments have shown that somatic embryos develop from proembryogenic masses which pass through a series of three characteristic stages distinguished by cellular organization and cell number (stages I, II and III) to transdifferentiate to somatic embryos. Microscopic inspection of different types of structures has revealed that proembryogenic masses are characterized by high interclonal variation of shape and cellular constitution. In contrast, somatic embryos are morphologically conservative structures, possessing a distinct protoderm-like cell layer as well as embryonal tube cells and suspensor. The lack of staining of the arabinogalactan protein epitope recognized by the monoclonal antibody JIM13 was shown to be an efficient marker for distinguishing proembryogenic masses from somatic embryos. The vast majority of cells in proembryogenic masses expressed this epitope and none of cells in the early somatic embryos. The conditions that promote cell proliferation (i.e. the presence of exogenous auxin and cytokinin), inhibit somatic embryo formation; instead, continuous multiplication of stage I proembryogenic masses by unequal division of embryogenic cells with dense cytoplasm is the prevailing process. Once somatic embryos have formed, their further development to mature forms requires abscisic acid and shares a common histodifferentiation pattern with zygotic embryos. Although the earliest stages of somatic embryo development comparable to proembryogeny could not be characterized, the subsequent developmental processes correspond closely to what occurs in the course of early and late zygotic embryogeny. A model for somatic embryogenesis pathways in Picea abies is presented.