Morphological characterization of domatium development in Callicarpa saccata. (26th November 2019)

• Record Type: Journal Article
• Authors: Sarath, Emma; Ezaki, Kazune; Sasaki, Takenori; Maekawa, Yu; Sawada, Yuji; Hirai, Masami Yokota; Soejima, Akiko; Tsukaya, Hirokazu
• Is Part Of: Annals of botany. Volume 125:Number 3(2020)
• Page Start: 521
• Page End: 532
• Publication Date: 2019-11-26
• Subjects: Ant plant -- Callicarpa saccata -- Callicarpa subaequalis -- development -- domatium -- gland -- Lamiaceae -- morphology -- mutualism -- myrmecophyte -- symbiotic; Botany -- Periodicals; 580
• DOI: 10.1093/aob/mcz193
• Languages: English
• ISSNs: 0305-7364

Abstract

Abstract: Background and aims: Domatia are plant structures within which organisms reside. Callicarpa saccata (Lamiaceae) is the sole myrmecophyte, or 'ant plant', that develops foliar (leaf-borne) myrmeco-domatia in this genus. In this work we examined domatium development in C. saccata to understand the developmental processes behind pouch-like domatia. Methods: Scanning electron microscopy, sectioning and microcomputed tomography were carried out to compare the leaves of C. saccata with those of the closely related but domatia-less myrmecophyte Callicarpa subaequalis, both under cultivation without ants. Key results: Callicarpa saccata domatia are formed as a result of excess cell proliferation at the blade/petiole junctions of leaf primordia. Blade/petiole junctions are important meristematic sites in simple leaf organogenesis. We also found that the mesophyll tissue of domatia does not clearly differentiate into palisade and spongy layers. Conclusions: Rather than curling of the leaf margins, a perturbation of the normal functioning of the blade/petiole junction results in the formation of domatium tissue. Excess cell proliferation warps the shape of the blade and disturbs the development of the proximal–distal axis. This process leads to the generation of distinct structures that facilitate interaction between C. saccata and ants.