Leaf Epidermal Morphology of Ten Wild Tree Peonies in China and Its Taxonomic Significance

Abstract

This research reports for the first time the epidermal characteristics of 10 wild tree peonies belonging to the sect. Moutan group. The leaf micromorphology of 10 wild tree peonies—P. qiui, P. decomposita, P. jishanensis, P. ostii, P. delavayi, P. lutea, P. potanini, P. rockii, P. ludlowii and P. cathayana—were investigated by light and scanning electron microscopy. The characteristics of the leaf epidermis were found to be constant at the species level, but variable among species. Patterns of anticlinal walls were slightly wavy to wavy, very wavy, and straight to curved. All studied tree peonies presented stomata only on the abaxial surfaces of the leaves. The stomatal apparatus was elliptical or rectangular. Stomatal density was highest on the abaxial surface in P. qiui (300.25 per mm2), and lowest in P. jishanensiss (198.41 per mm2). Stomatal Index was highest on the adaxial surface of P. potanini (27.30%), and lowest in P. ludlowii (18.35%). Trichomes were observed in four studied peonies, which appeared only on the abaxial surface of the leaves, and three basic types of trichomes were identified. The long conical trichomes were distinctive of P. jishanensis, and the flat-shaped trichomes were characteristic of P. qiui, P. rockii and P. cathayana, and commonly occurred in the intervenous region and leaf veins. Stomatal shape, stomatal density, anticlinal wall patterns and trichomes may be of great value and significance for the classification of wild tree peonies. The principal component analysis showed that the component 1, component 2 and component 3 were the most components and nearly 79% of the observed variation. The key to the identification of wild tree peonies based on trichomes and stomata diversity was provided.

Development and Biomechanics of Grewia lasiocarpa E. Mey. Ex Harv. Trichomes Exudate

“…Trichomes or epidermal hairs are usually found in ferns and flowering plants and are used as a taxonomic tool [41]. They are usually found on fruits, stem, leaves and exterior or margins of sepals.…”

Petal Morphology Is Correlated with Floral Longevity in Paeonia suffruticosa

“…The surfaces of epidermal cells on the petals were examined by scanning electron microscopy (SEM). The cross-sectional anatomy of the petals was prepared following the method detailed by Chavarria et al [34] and Olsen et al [35] and visualized under a light microscope (LM) [36][37][38]. Several anatomical characteristics including petal thickness, number of petal cell layers, cuticle thickness, mesophyll thickness, adaxial epidermal thickness, abaxial epidermal thickness, and vessel diameter were measured with the help of the Olympus cellSens standard software [37].…”

“…These paraffin sections were stained with safranin and fast green dye [41], and observed and photographed under a fluorescence microscope (BX53, Olympus, Tokyo, Japan). Petal thickness, cuticle thickness, adaxial epidermal thickness, abaxial epidermal thickness, and mesophyll thickness of the petals were determined with the help of the Olympus cellSens standard software 1.12 [37]. Vein density was measured as the total length of the vascular tissue per mm 2 of petal surface area.…”

Characteristics and Evolution of Leaf Epidermis in the Genus Amana Honda (Liliaceae)

“…For example, Fan et al [1] used epidermis cell morphology, cuticular wax, stomatal distribution, morphology, and the stomatal index to classify Holcoglossum Schltr. Jia et al classified tree peonies based on stomatal morphology, stomatal density, vertical wall morphology, and trichome morphology [2].…”