Sanches Miller Melo, Guesdon Isabel Reis, Alves Meira Renata Maria Strozi
Programa de Pós-Graduação em Botânica, Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Av. P.H. Rolfs, S/N, Campus Universitário, Viçosa, Minas Gerais, 36570-000, Brazil.
Universidade Federal do Amazonas, Instituto de Ciências Exatas E Tecnologia, Campus de Itacoatiara, Itacoatiara-AM, CEP, 69103-128, Brazil.
Protoplasma. 2023 Nov;260(6):1555-1567. doi: 10.1007/s00709-023-01871-5. Epub 2023 Jun 20.
Lophopterys floribunda is a Neotropical species of Malpighiaceae endemic to Brazil, occurring in both the Amazon and Atlantic Forest. Instead of the typical bi-glandular sepals reported for Neotropical Malpighiaceae, this species presents a single, large gland on the lateral sepals. In addition, ant patrolling was observed at the apex of bracts and bracteoles during fieldwork. Thus, this work aimed to describe the sepalar gland of L. floribunda and other secretory structures in its flowers and inflorescence. Samples of bracts, bracteoles, sepals, petals, and anther were collected and submitted to usual anatomical techniques. Unexpected nectaries at the apex of bracts and bracteoles, not visible to the naked eye, were described and represent a new type of structure for the family due to both their position and size. Mutualistic ants consume the exudate produced by these tiny nectaries, and such structures enable a specific visitation pattern for Lophopterys. Typical epithelial elaiophores occur on the lateral sepals, formed by an invaginated epidermis, which predominantly produce lipid secretion. The petal marginal glands are anatomically similar to the standard type of colleter, which exude mucilaginous substances. The exudate produced by the petal marginal glands was considered to have an additional role of contributing to the maintenance of the closed bud during the beginning of development. The globose epidermal cells containing lipids, proteins, and polysaccharides observed in the connective may be responsible for the typical aroma emitted by these flowers. The diversity of secretory structures reported here has application in both systematic and ecological studies of Malpighiaceae.
多花羽叶树是金虎尾科的一种新热带植物，为巴西特有种，分布于亚马逊和大西洋森林。该物种的侧萼片上没有新热带金虎尾科植物典型的双腺体萼片，而是有一个单一的大腺体。此外，在野外工作期间，观察到苞片和小苞片顶端有蚂蚁巡逻。因此，这项工作旨在描述多花羽叶树的萼片腺体及其花和花序中的其他分泌结构。采集了苞片、小苞片、萼片、花瓣和花药的样本，并采用常规解剖技术进行处理。在苞片和小苞片顶端发现了肉眼不可见的意外蜜腺，由于其位置和大小，这代表了该科一种新型结构。互利共生的蚂蚁消耗这些微小蜜腺产生的分泌物，这些结构使羽叶树有特定的访花模式。典型的上皮油脂体出现在侧萼片上，由内陷的表皮形成，主要产生脂质分泌物。花瓣边缘腺体在解剖学上类似于标准类型的分泌毛，分泌粘液物质。花瓣边缘腺体产生的分泌物被认为在发育初期对维持闭合的花蕾有额外作用。在药隔中观察到的含有脂质、蛋白质和多糖的球状表皮细胞可能是这些花散发出典型香气的原因。这里报道的分泌结构的多样性在金虎尾科的系统学和生态学研究中都有应用。
