Abstract

PERISSE, P et al. Seed and seedling morphology of Dicliptera squarrosa Nees (Acanthaceae) as a character identification source, and its relationship with survival structures. Phyton (B. Aires) [online]. 2011, vol.80, n.1, pp.73-78. ISSN 1851-5657.

Dicliptera squarrosa Nees, "canario rojo", "coral de campo" or "ajicillo", is a perennial native herb of the north, center and east of Argentina. It is cited as an ornamental, apiarian, emergency forage plant, and as a glyphosate-tolerant weed. The objectives were to characterize the seed and seedling of D. squarrosa and to establish the relationships with the structures that ensure its survival. The materials were treated with the conventional methodology to perform morphological studies, using stereoscopically and optical microscopy. The germination assays were carried out to determine the germination percentage and the germination type. The weight of 1000 seeds was also established. Seeds are of circular contour (2.5 x 2 mm), the seed coat is verrucose, reddish-black with branched trichomes with spiral wall thickenings. The hilum and the micropyle are in subapical position. The seed is exendospermic, the curved embryo is sorrounded by a thin layer of endosperm; the 1000 seed weight is 0.8065 g. The germination is faneroepigeal, the seedling has cotyledons with pubescent petioles, obovate asymmetric and emarginated laminae with glandular trichomes; it has opposite nomophylles, petiolated with ovate laminae with curved, simple trichomes and glandular trichomes. Seedling agrees with the Chimonanthus and Macaranga morphological types. The root is diarch and becomes an eustele at the hypocotyl level. Along the caulinar axis six ribs of collenchyma alternating with a continuous chlorenchyma and the presence of lythocysts are observed. In cotyledons and nomophylls, the epidermis presents fundamental cells on both leaf sides with undulated anticlinal walls, diacytic stomata, and simple and double lithocysts; in both cases the mesophyll is dorsiventral. Adventitious and contractile roots were developed in the hypocotyl and in the basal internodes. The seminal characteristics and the development of stolons and short rhizomes explain the dispersion, the establishment and the persistence of this species.

Keywords : Dicliptera squarrosa; Seed; Seedling; Rhizome; Stolon; Dissemination.

        · abstract in Spanish     · text in Spanish     · Spanish ( pdf )