Souto Letícia Silva, Oliveira Denise Maria Trombert
Departamento de Biologia, Centro de Ciências e Tecnologias para Sustentabilidade, UFSCar-Universidade Federal de São Carlos, campus Sorocaba, Sorocaba, São Paulo, Brasil; Programa de Pós-Graduação em Ciências Biológicas (Botânica), Instituto de Biociências, UNESP-Universidade Estadual Paulista, Botucatu, São Paulo, Brasil.
Departamento de Botânica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brasil.
C R Biol. 2014 Jan;337(1):62-70. doi: 10.1016/j.crvi.2013.11.001. Epub 2013 Dec 27.
Malpighiaceae ovules have a well-developed nucellus; previous observations indicate that during seed development, the endosperm does not proliferate, thus, remaining scarce. This study aimed at identifying the nutritive tissues during seed development in Malpighiaceae, focusing especially on the endosperm. We analysed the seed development of Janusia mediterranea, J. occhionii, Mascagnia cordifolia, and Tetrapterys chamaecerasifolia, which were collected and processed by traditional methods for light microscopy. Ovules are subcampylotropous, crassinucellate and unitegmic in Janusia and bitegmic in M. cordifolia and T. chamaecerasifolia. The nucellus is well developed and protrudes through the micropyle, touching the funicular obturator. During development, a pachychalaza is formed, and the integuments coalesce in bitegmic species. Through a series of nucellar cell divisions, the perisperm is formed. In Janusia species, the endosperm is not produced. In M. cordifolia and T. chamaecerasifolia, the endosperm is nuclear, but it is scarce and ephemeral. The mature seed is exalbuminous, and the perisperm is consumed, and thus, the mature embryo is total. The absence of endosperm in Janusia is newly observed for the family and indicates functional transfer for the abundant perisperm.
金虎尾科植物的胚珠具有发育良好的珠心；先前的观察表明，在种子发育过程中，胚乳不增殖，因此仍然稀少。本研究旨在确定金虎尾科植物种子发育过程中的营养组织，尤其关注胚乳。我们分析了地中海雅努西亚木、奥基奥尼雅努西亚木、心形马斯卡尼亚木和矮叶四翅木的种子发育情况，这些植物通过传统方法采集并处理用于光学显微镜观察。雅努西亚木的胚珠为近弯生、厚珠心且单珠被，而心形马斯卡尼亚木和矮叶四翅木的胚珠为双珠被。珠心发育良好，穿过珠孔突出，触及珠柄塞。在发育过程中，形成了厚珠脐，在双珠被物种中珠被愈合。通过一系列珠心细胞分裂，形成了外胚乳。在雅努西亚木属植物中，不产生胚乳。在心形马斯卡尼亚木和矮叶四翅木中，胚乳为核型，但稀少且短暂。成熟种子无胚乳，外胚乳被消耗，因此成熟胚完整。雅努西亚木属植物中不存在胚乳这一现象是该科新观察到的，表明丰富的外胚乳具有功能转移作用。
