Costa Ellenhise R, Tangerina Marcelo M P, Ferreira Marcelo J P, Demarco Diego
Departamento de Botânica, Instituto de Biociências, Universidade de São Paulo, São Paulo CEP 05508-090, Brazil.
Plants (Basel). 2021 Apr 27;10(5):877. doi: 10.3390/plants10050877.
Secretory ducts have been reported for more than 50 families of vascular plants among primary and secondary tissues. A priori, all ducts of a plant are of the same type, and only slight variations in the concentration of their compounds have been reported for few species. However, two types of secretion were observed in primary and secondary tissues of , leading us to investigate the possible influence of duct origins on the structure and metabolism of this gland. has primary ducts in the cortex and pith and secondary ducts in the phloem. Both ducts are composed of uniseriate epithelium surrounded by a sheath and a lumen formed by a schizogenous process. Despite their similar structure and formation, the primary ducts produce resin, while the secondary ducts produce gum. This is the first report of two types of ducts in the same plant. The distinct origin of the ducts might be related to the metabolic alteration, which likely led to suppression of the biosynthetic pathway of terpenoids and phenolics in the secondary ducts. The functional and evolutionary implications of this innovation are discussed in our study and may be related to the diversification of and Calophyllaceae in tropical environments.
在维管植物的50多个科中，已报道在初生组织和次生组织中存在分泌导管。据推测，一种植物的所有导管都属于同一类型，并且仅报道了少数物种其化合物浓度存在细微差异。然而，在[植物名称]的初生组织和次生组织中观察到了两种类型的分泌，这促使我们研究导管起源对这种腺体结构和代谢的可能影响。[植物名称]在皮层和髓中有初生导管，在韧皮部中有次生导管。两种导管均由单层上皮组成，周围有一层鞘，以及一个由裂生过程形成的腔。尽管它们的结构和形成方式相似，但初生导管产生树脂，而次生导管产生树胶。这是同一植物中两种类型导管的首次报道。导管的不同起源可能与代谢改变有关，这可能导致次生导管中萜类化合物和酚类化合物生物合成途径的抑制。我们的研究讨论了这一创新的功能和进化意义，并且可能与[植物名称]和红厚壳科在热带环境中的多样化有关。
