Anatomical research on Potentilla indica (Rosaceae)

Abstract

Introduction: Potentilla indica (Jacks.) Th. Wolf commonly known as Indian Mock Strawberry or false strawberry, is native to eastern and southern Asia (Himalayas, China, and Japan), but has been introduced worldwide and commonly grown as ornamental. P. indica is very tolerant to different environmental conditions including high-altitude habitat, areas with low/high temperatures, sun/ shade or drought. Objectives: The aim of the research is to contribute to the ecophysiological study of the plant by analyzing the anatomical characteristics that could be involved in response of plants to environmental stimuli and the adaptation to abiotic stress. Materials & methods: For light microscopy fixed plant material (petiole, leaf blade, stem, stolons, rhizome and adventitious root) was dehydrated and embedded in paraffin. Sections were cut by sliding microtome and stained with Alcian Blue-Safranin. Observation and photographs were done using a light microscope (Leica DM2000). Results: Leaves are dorsiventral and amphistomatic (Fig 1a). Two types of trichomes are identified, non-glandular and glandular present on both leaf surfaces. Non-glandular trichomes are unicellular, while glandular ones have uniseriate stalk and globular head, usually made up of four cells each (Fig 1b). Palisade parenchyma is composed of two or three layers of elongated cells while spongy parenchyma is composed of a few layers of cells with prominent intercellular spaces. In stolons subepidermal collenchyma is followed by one or two chlorenchyma layers and large cortical parenchyma cells (Fig 1c). Pericycle is composed of continuous ring of sclerenchyma cells (Fig 1d). Vascular bundles are open collateral, separated by parenchyma rays between. Peridermis, cortical parenchyma and collateral vascular bundles are observed in the cross section of the rhizome and pith parenchyma occupying the large area in the central part (Fig 2a, b, c). In adventitious roots diarch, triarch, tetrarch or polyarch radial vascular bundles occur depending on the stage of development (Fig 2d, e). Older roots have typically developed secondary xylem and phloem, and in external parts of roots are visible rings of secondary meristem (Fig 2f). Cubic crystals, probably of calcium oxalate, are randomly scattered predominantly in pith region of stem and in leaf mesophyll. Conclusion: Some of anatomical features of P. indica are quite common but it also has some specific performances, especially in roots, what will be discussed. Considering the ability to withstand high-temperature and low-temperature stress, additional physiological studies are also required.