Institute of Molecular Plant Sciences, University of Edinburgh, Edinburgh, UK.
Protoplasma. 2010 Dec;247(3-4):195-214. doi: 10.1007/s00709-010-0184-y. Epub 2010 Jul 27.
The formation of viable angiosperm seeds involves the co-ordinated growth and development of three genetically distinct organisms, the maternally derived seed coat and the zygotic embryo and endosperm. The physical relationships of these tissues are initially established during the specification and differentiation of the female gametophyte within the tissues of the developing ovule. The molecular programmes implicated in both ovule and seed development involve elements of globally important pathways (such as auxin signalling), as well as ovule- and seed-specific pathways. Recurrent themes, such as the precisely controlled death of specific cell types and the regulation of cell-cell communication and nutrition by the selective establishment of symplastic and apoplastic barriers, appear to play key roles in both pre- and post-fertilization seed development. Much of post-fertilization seed growth occurs during a key developmental window shortly after fertilization and involves the dramatic expansion of the young endosperm, constrained by surrounding maternal tissues. The complex tissue-specific regulation of carbohydrate metabolism in specific seed compartments has been shown to provide a driving force for this early seed expansion. The embryo, which is arguably the most important component of the seed, appears to be only minimally involved in early seed development. Given the evolutionary and agronomic importance of angiosperm seeds, the complex combination of communication pathways which co-ordinate their growth and development remains remarkably poorly understood.
有活力的被子植物种子的形成涉及三个在遗传上截然不同的生物体的协调生长和发育,即母体来源的种皮和受精卵及胚乳。这些组织的物理关系最初是在发育中的胚珠组织内雌性配子体的特化和分化过程中建立的。涉及全球重要途径(如生长素信号转导)的分子程序以及胚珠和种子特异性途径都与胚珠和种子发育有关。反复出现的主题,如特定细胞类型的精确控制死亡以及通过选择性建立质外体和共质体屏障来调节细胞间通讯和营养,似乎在受精前和受精后种子发育中都发挥着关键作用。受精后种子的大部分生长发生在受精后不久的一个关键发育窗口内,涉及年轻胚乳的剧烈扩张,受到周围母体组织的限制。已经表明,在特定种子隔室中碳水化合物代谢的复杂组织特异性调节为这种早期种子扩张提供了动力。胚胎,可说是种子中最重要的组成部分,在早期种子发育中似乎只起很小的作用。鉴于被子植物种子在进化和农业方面的重要性,协调其生长和发育的复杂通讯途径组合仍然知之甚少。