Homogeneous colleters in Myrteae (Myrtaceae)

Area of Science:

• Botany
• Plant Anatomy
• Secretory Structures

Background:

• Colleters are secretory structures found in over 60 plant families, with three types (petaloid, conical, euriform) previously identified in Myrtaceae.
• Myrtaceae species in Argentina inhabit diverse regions, from subtropical areas to Patagonia's temperate rainforests.

Purpose of the Study:

• To investigate the presence, morphology, and secretion products of colleters in five species of the subfamily Myrtoideae, tribe Myrtea.
• To analyze colleters in vegetative buds of species native to Patagonia and Corrientes, Argentina.

Main Methods:

• Optical and scanning electron microscopy were employed to identify colleters in vegetative organs.
• Histochemical tests were conducted to determine the main secretion products of these structures.

Main Results:

• Colleters were found on leaf primordia, cataphylls, and petioles, replacing stipules.
• Homogeneous colleters, lacking vascularization and originating from the protodermis, were observed.
• Conical colleters were identified in Luma apiculata, Myrcianthes pungens, and Eugenia moraviana; euriform colleters in Amomyrtus luma and Myrceugenia exsucca.
• Secretions included lipids, mucilage, phenolic compounds, and proteins.

Conclusions:

• This study provides the first description of colleters in the analyzed Myrtaceae species.
• The morphological types and secretion products of colleters hold potential taxonomic and phylogenetic significance within the Myrtaceae family.