Leaf epidermal micromorphology in Aspidistra (Asparagaceae): diversity and taxonomic significance.

Nikolay A. Vislobokov,Yi-Gang Wei,Maxim S. Nuraliev,Long-Fei Fu

doi:10.3897/phytokeys.185.72259

Nikolay A. Vislobokov, Yi-Gang Wei + Show 2 more

Open Access

https://doi.org/10.3897/phytokeys.185.72259

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Abstract

Micromorphological characters of leaf epidermis were investigated in 69 species of Aspidistra using scanning electron microscopy. Sculpture of epidermis varies from smooth to verrucose and rugose in the genus. The abaxial epidermis of some species bears papillae, whereas the adaxial surface uniformly lacks the papillae. Sculpture type of epidermis and density of papillae are generally found to be stable characters at a species level. The infraspecific variation of epidermis sculpture, where present, ranges from smooth to verrucose or from verrucose to rugose. Micromorphological characters of leaf epidermis are shown to have potential taxonomic significance in Aspidistra; in combination with the type of shoot structure, they allow to subdivide the species into 13 groups. The groups are largely incongruent with floral morphological traits. An identification key to the studied species of Aspidistra based on vegetative characters (gross leaf and shoot morphology and characters of leaf epidermis) is presented.

Highlights

Aspidistra Ker Gawl., belonging to the family Asparagaceae, is a large genus of herbaceous plants which inhabits tropical and subtropical forests of Asia
The species of Aspidistra can be divided into two groups: the first group is characterized by solitary leaves, and in the second group the leaves are arranged in tufts (i.e., 3–5 foliage leaves per elementary shoot)
Our goals were (1) to evaluate diversity of adaxial and abaxial leaf epidermis in Aspidistra including cell sculpture and density of papillae; (2) to determine infraspecific variation of these characters; (3) to analyze taxonomic significance of characters of leaf epidermis by delineating species groups on the basis of these characters; (4) to compile an identification key to the studied species of Aspidistra based on vegetative features, including leaf and shoot morphology and the characters of leaf epidermis

Summary

Introduction

Aspidistra Ker Gawl., belonging to the family Asparagaceae, is a large genus of herbaceous plants which inhabits tropical and subtropical forests of Asia. A few species have erect stem (e.g. A_erecta Yan Liu & C.I Peng and A. globosa Vislobokov & Nuraliev), representing a group recognizable by vegetative morphology (Vislobokov et al 2016) Another non-floral character that was shown to have taxonomic significance in Aspidistra is the distribution of foliage leaves along the shoot (De Wilde and Vogel 2006; Averyanov and Tillich 2014). The species of Aspidistra can be divided into two groups: the first group is characterized by solitary leaves (i.e., one foliage leaf per elementary shoot), and in the second group the leaves are arranged in tufts (i.e., 3–5 foliage leaves per elementary shoot) These groups of species differ in the gross morphology of leaf. The second group is much smaller with respect to species number than the first one

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