Morphoanatomy and stigma receptivity in Tillandsia L. (Bromeliaceae) occurring in Bahia, Brazil

Abstract

Species of Tillandsia L. are widely distributed in Brazilian ecosystems, and in the state of Bahia they can be found in the Atlantic Forest, Caatinga and Cerrado biomes. Studying the reproductive aspects of these species can support their management and conservation. In particular, stigma morphology is a conserved trait of Bromeliaceae and stigma receptivity can influence the success of pollination. The objective of this study was to characterize the morphoanatomy and classify the stigma types of Tillandsia species by means of light and scanning electron microscopy, as well as to evaluate the stigma receptivity by different methods and at three floral development stages. A total of 21 Tillandsia species found in Bahia were evaluated. The stigma receptivity was assessed with hydrogen peroxide (3%) and a solution of α‐naphthyl acetate. Four stigma types were observed: conduplicate‐spiral for the species of the Tillandsia subgen. Tillandsia, simple‐erect for species of T. subgen. Diaphoranthema, and simple‐truncate for the species of T. subgen. Phytarrhiza. The species of the T. subgen. Anoplophytum had three morphological types, conduplicate‐spiral, conduplicate‐patent and simple‐erect. All the species had trifid stigmas, monostratified epidermis, numerous idioblasts containing raphides in the fundamental parenchyma and an individual vascular bundle for each carpel. In all the species studied by the two methods of stigma receptivity the highest enzyme activity was observed during anthesis. The morphoanatomy of the stigma and style provides important information for the taxonomy of Tillandsia and the data on stigma receptivity can support studies of the reproduction and conservation of these species.