Palyno-Anatomical Studies of Rosaceous Taxa from District Swat, Pakistan

Abstract

This study was aimed to investigate stomatal and pollen diversity in Rosaceous taxa from district Swat, Pakistan, and the possible taxonomic potential of stomatal and pollen diversity in identification of plant species. Plant samples were gathered from District Swat-Pakistan, some of them were taken from temperate along with some species from alpine ecological locations. The study revealed micro anatomical features of foliar epidermal and pollen morphology of 50 species in 19 genera belonging to family Rosaceae. For foliar epidermal anatomy lactic acid protocol was used to investigate both abaxial and adaxial surfaces while for pollen morphology acetic acid protocol was used under light microscope. Two types of trichomes were observed during microscopy, glandular trichome were mostly capitate while non-glandular trichome were mostly conical cylindrical. Both surfaces of the leaves exhibited differences in their leaf anatomical traits including type of stomata, epidermis, anticlinal wall, lobes, and diversity of trichomes. The epidermal cells shape reported as trigonal, tetragonal, pentagonal, hexagonal, irregular, wavy and polygonal. The largest epidermal cells were examined in Duchesnea indica (89.1 μm) on abaxial surface while on adaxial surface in Sanguisorba minor (78.8 μm) respectively. Seven distinct stomatal types were counted. Most Rosaceous taxa exhibit stephanocytic and paracytic stomata. The largest stomatal complex was recorded in Duchesnea indica (105.5 μm) and Geum elatum (100.8 μm), while smallest in Malus pumila (23.7 μm). Pollen grains of Rosaceous species were acetolyzed and observed under light microscope. Both qualitative and quantitative bioinformatic data were analyzed and measured through statistical software. Rosaceous taxa showed pollen variation in both qualitative and quantitative measurement including polar and equatorial measurment, length, and girth of pollen colpi and mesocolpium, exine thicken, pollen shape class and type of pollen. Based on pollen type only 3 types of pollen were observed in Rose family, tricolpate, tricolporate while a single tetracolpate is observed in Cotoneaster nummularius. Most of Rosaceous species showed prolate and sub-prolate pollen class. The largest polar diameter was observed in Prunus armeniaca (44.25 μm) while smallest were observed in Spiraea canescens (10.4 μm). The results of this investigation showed that micromorphological characteristics had taxonomic significance, that provide base line for correct identification of Rosaceous taxa using taxonomic keys.