Petal and Sepal Epidermal Micromorphology of Six Lathyrus Taxa (Fabaceae) and their Systematic Value

Musa Dogan,Hã¼Seyin Cildir,Ahmet Kahraman

doi:10.15835/nbha4017503

Abstract

In this study, the epidermal types and their distribution on dorsal and lateral petals, the trichome types and their density on sepals of Lathyrus chloranthus, L. digitatus, L. laxiflorus subsp. laxiflorus, L. roseus subsp. roseus, L. sativus, and L. tuberosus, belonging to sections Lathyrus, Lathyrostylis, Pratensis, and Orobon of the genus Lathyrus in Turkey were investigated using light microscopy (LM) and scanning electron microscopy (SEM), and the systematic significance of these characters was evaluated. These taxa, except L. sativus, are studied for the first time under aspects of the petal and sepal micromorphology. Three major epidermal types were recognized on the petal: tabular rugose striate cells (TRS), areolate cells with more or less striations (AS), and papillose conical striate cells (PCS). TRS and AS were further subdivided into three subtypes. TRS was found on the dorsal and lateral petals of L. chloranthus, L. sativus, and L. tuberosus: the dorsal petals of L. roseus subsp. roseus and the lateral petals of L. laxiflorus subsp. laxiflorus, while AS was present on the dorsal and lateral petals of L. digitatus and the lateral petals of L. roseus subsp. roseus. PCS was found only on the dorsal petals of L. digitatus. Three main types of trichomes on the sepal were observed: peltate glandular, capitate glandular, and nonglandular trichomes. The capitate glandular and nonglandular trichomes were further subdivided into three subtypes. The peltate glandular trichomes were present only in L. chloranthus, but absent in the others. The capitate glandular trichomes were found in L. chloranthus, L. laxiflorus subsp. laxiflorus, L. roseus subsp. roseus, and L. tuberosus. The nonglandular trichomes were always present in L. chloranthus and L. laxiflorus subsp. laxiflorus. The present results show that the petal and sepal micromorphology can be used in delimitation of the taxa based on petal and sepal micromorphology.

Highlights

Lathyrus L. (Fabaceae) is the largest genus in the economically important tribe Fabeae of the subfamily Papilionoideae, with approximately 170 species worldwide (ILDIS, 2010; Lewis et al, 2005)
This study aims to investigate the epidermal types and their distribution on dorsal, and lateral petals and the trichome types and their density on sepals of these six taxa from four sections, namely Lathyrus, Lathyrostylis, Pratensis, and Orobon distributed in Turkey, and to evaluate the systematic value of these characters
After a number of specimens had been compared under light microscopy (LM), three to six petals and sepals were examined for each species under scanning electron microscopy (SEM)

Summary

Introduction

Lathyrus L. (Fabaceae) is the largest genus in the economically important tribe Fabeae of the subfamily Papilionoideae, with approximately 170 species worldwide (ILDIS, 2010; Lewis et al, 2005). Most researchers separate Lathyrus into 12 or 13 sections (Asmussen and Liston, 1998; Czefranova, 1971; ILDIS, 2002; Kupicha, 1983; Leht, 2009). Kupicha’s (1983) infrageneric classification is the only worldwide treatment of the genus She divided it into 13 sections based on morphological traits: Orobus, Lathyrostylis, Lathyrus, Orobon, Pratensis, Aphaca, Clymenum, Orobastrum, Viciopsis, Linearicarpus, Nissolia, Neurolobus and Notolathyrus. Most recent molecular phylogenetic studies (Croft et al, 1999; Kenicer et al, 2005) generally support Kupicha’s (1983) classification

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