Descrição da arquitetura foliar e análise morfométrica das folhas de Spathicarpa Hook (Araceae)

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

The study of leaf morphology has always played a significant role in plant taxonomy, especially in the identification of taxa which are defined by reproductive characteristics such as genus Spathicarpa Hook. (Araceae). The present study has as its objective: to describe leaf architechture patterns and to characterize by morphometric methods the leaves of Spathicarpa gardneri Schott, S. hastifolia Hook., S. lanceolata Engl. and S. sagittifolia Schott in a search for vegetative taxonomically diagnostic characters in the genus. A total of 185 specimens were sampled, 48 of S. gardneri, 54 of S. gardneri, 48 of S. lanceolata, and 35 of S. sagittifolia, collected from 9 different accessions growing under the same environmental conditions. Along general lines, the successful leaf clearing technique developed involved initially maintaining leaves in ethyl alcohool 70% with comercial detergent, sodium hydroxide (5%) and sodium hipochloride for clearing and whitening, respectively. The leaves were then run through a dehydration ethanol series (10 to 100%) and through a xylene series (xylene-ethanol 100% 1:1 and xylene). As a last step, leaves were died with safranin and then put again into xylene-ethanol 100% 1:1 to differentiate. Leaf countours were digitally reconstructed using Fourier elliptic analysis with 20 harmonics. The normalized coeficients obtained were treated as variables capable of representing the contour of the 185 leaves in bidimensional space, as well as potential leaf contour variation. These variables were treated statistically by multivariate analysis. Amongst the four species treated, only S. lanceolata presents diagnostic leaf characteristics. It is not possible to differentiate, neither on the basis of leaf architecture nor Fourier elliptic analysis of leaf contours, amongst the remaining three species. These results show that morphological circumscription of species S. gardneri, S. hastifolia and S. sagittifolia based on leaf characters is not possible

ASSUNTO(S)

análise elíptica de fourier botanica lobules elliptic fourier analysis técnica de diafanização morphometrics leaf architecture arquitetura foliar lóbulos morfometria technique for leaf clearing

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