The impact of seed micromorphology in the subgeneric classification of the genus Reseda L. (Resedaceae) in Turkey.

Abstract

Seed micromorphology of 18 taxa belonging to the genus Reseda (Resedaceae) in Turkey were investigated with scanning electron microscopy (SEM), in order to understand and check its diagnostic significance at subgeneric and sectional level. Seeds of Reseda species were photographed to evaluate different characteristics including appearance of the seed, testa ornamentation and the existence of carunculoid tissue at hilum regions. In addition, cluster analysis and principal component analysis (PCA) were performed to test whether the micromorphological data of the related taxa is compatible with the current classification of the genus. According to seed micromorphology, Reseda taxa in Turkey are divided into four main groups particularly by testa ornamentation as papillose, rugose, rugulose, and smooth. These results are also in agreement with the sectional classification of the genus in morphological and molecular perspective. The tree topology of Unweighted Pair Group Method with Arithmetic Average based on seed features supported the traditional classification. Principle component analysis revealed testa surface ornamentation as the most distinctive character for species identification. PCA also confirms our cluster grouping of the subgeneric and sectional classification of the taxa in Turkey. An identification key for the genus Reseda in Turkey is provided in the light of current data. The seed data is helpful for the identification of the genus Reseda in Turkey at sectional level. However, for an accurate identification at specific level, seed micromorphology is not sufficient alone and must be evaluated together with all diagnostic morphological features.