Instituto de Botánica del Nordeste, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad Nacional del Nordeste , Sargento Cabral 2131, C. C. 209, C. P. 3400, Corrientes, Argentina.
Facultad de Ciencias Exactas y Naturales y Agrimensura, Universidad Nacional del Nordeste, Avenida Libertad 5470, C. P. 3400. Corrientes, Argentina.
An Acad Bras Cienc. 2022 Aug 8;94(2):e20201975. doi: 10.1590/0001-3765202220201975. eCollection 2022.
Colleters are glandular structures related to young shoots protection. In several Angiosperm families, as in Rubiaceae colleters are taxonomically important. This study reports presence, location, morpho-anatomical structure, ontogeny and histochemistry of colleters in vegetative and reproductive organs in 6 species of Cephalanthus and 20 species representatives of the tribe Naucleeae. Primarily based on their color and their secretion color, they were classified into light (LC) and dark (DC) colleters. The LC are exclusive to the inner side of the stipule, while the DC are found in several vegetative and reproductive organs. Histochemical studies revealed that higher mucilage and phenol content in DC could explain the dark color secretion. Results were analyzed at genus, tribe and subtribe levels, evidencing the taxonomic relevance in the family. Finally, the presence of corolline colleters in angiosperm flowers was reviewed. It was confirmed that, besides Cephalanthus, they are only present in Adenoa (Passifloraceae) and Chamaecrista (Fabaceae). Therefore, structures described as colleters in Nerium (Apocynaceae) and Cuscuta (Cuscutaceae) corollas do not correspond to colleters. This proves that corolline colleter is a rare character in Angiosperms. To conclude we provide a record of presence/absence, type and distribution of corolline colleters in an Angiosperm phylogenetic tree.
叶腺是与幼芽保护有关的腺性结构。在几个被子植物科中，如茜草科，叶腺在分类上具有重要意义。本研究报告了在 Cephalanthus 的 6 个种和 Naucleeae 族的 20 个代表种的营养和生殖器官中叶腺的存在、位置、形态解剖结构、发生和组织化学。主要根据它们的颜色和分泌物的颜色，将其分为浅色（LC）和深色（DC）叶腺。LC 仅存在于托叶的内侧面，而 DC 则存在于几个营养和生殖器官中。组织化学研究表明，DC 中较高的黏液和酚含量可以解释其深色分泌物。结果在属、族和亚科水平上进行了分析，证明了在该科中的分类学相关性。最后，对被子植物花中叶腺的存在进行了综述。证实除 Cephalanthus 外，叶腺仅存在于 Adenoa（西番莲科）和 Chamaecrista（豆科）中。因此，在 Nerium（夹竹桃科）和 Cuscuta（旋花科）的花冠中描述为叶腺的结构并不对应于叶腺。这证明了在被子植物中，瓣状叶腺是一个罕见的特征。总之，我们提供了一个在被子植物系统发育树上瓣状叶腺的存在/缺失、类型和分布的记录。
