Morphological characterization of domatium development in Callicarpa saccata.

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.

Cedrela domatifolia (Meliaceae), un nuevo registro de cedro para el Perú

Cedrela domatifolia W. Palacios es registrada por primera vez para Perú en el valle de Chanchamayo, departamento de Junín. Con esta adición se elevan a 11 especies del género Cedrela (Meliaceae) en el Perú. La característica vegetativa más resaltante de C. domatifolia son los domacios prominentes, situados en las axilas de los nervios secundarios de las láminas por el envés. En caracteres florales, los pétalos son de color rojo a fucsia, una característica no común en el género.

A new record of Cedrela domatifolia W. Palacios is presented in Chanchamayo Valley, department of Junin, which adds to 11 the number of Cedrela (Meliaceae) species recorded in Peru. The most notorious vegetative character of the species are the prominent domatia in the axils of the secondary nerves of blades. At floral characters, the petals are red to fuchsia, an uncommon feature in the genus.