Abstract

GONZALEZ, Ana Maria  and  MERCEDES ARBO, María. Morpho-anatomy of ovule and seeds of Turnera and Piriqueta (Turneraceae). Bot. sci [online]. 2013, vol.91, n.4, pp.399-416. ISSN 2007-4476.

Some morphological characters of seeds are important in taxonomy of the Turneraceae family, and have been used to distinguish genera and species. However their anatomy has been studied only in a few species. The seeds of Piriqueta and Turnera, the most numerous genera of the family were analyzed -including all the series of the last one- in order to fulfill the information about development and variation of the morph-anatomical characters. The goals were to depict and circumscribe the variants, to check their taxonomic value. The anatomy of ovules is alike in all analyzed species. The integuments are not multiplicative, the outer one makes up the seed testa, with two layers, and the inner integument develops the tegmen with three layers. The seed coat basic structure is composed of areoles (made up by the giant cells of endotesta) delimited by muri (set out by exotegmen sclereids). Some species of Turnera and Piriqueta have one or two dot-like hollows in each areole, set up by protrusions of the endotesta cells with labyrinth walls on the inner face. The seed coat shows two basic types: reticulate and crested. According to the degree of development of transverse muri, the reticulate type shows two subtypes. The most common is the reticulate subtype, found in Piriqueta and in several series of Turnera. The striate-reticulate subtype, with transverse muri hardly visible, is found in species of some series of Turnera. The crested seed coat, found exclusively in T. sidoides, comes out when groups of exotesta cells grow developing crests of different height, which cover and hide the basic design. In many species of Piriqueta, the exotesta shows finger-like papillae while in Turnera it displays other types of papillae. The aril is inserted around the hilum in Piriqueta and in most species of Turnera, but in two species of series Anomalae and two of subseries Umbilicatae it is inserted also along the basal segment of the raphe. Turnera includes 66% of the species of the family, and in agreement it shows the towering diversity in seed morphology.

Keywords : aril; ovule; seed coat; tegmen; testa; Turneraceae.

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