Palynological investigation of Allergenic and Melliferous flora of Pakistan

Abstract

The microscopic analysis of pollen is the standard method and an effective tool to understand the allergenic (Pollen allergy) and melliferous plants (mellisopalynology) of any specific region. This is the first report study from Pakistan regarding pollen investigation of allergenic and melliferous flora using various techniques including pollen extraction, identification, systematics, field emission scaning electron microscopy, upright florescence microscopy and light microscopy. The study confind palynological analysis of melliferous plants and allergenic plants, pollen sculpturing using scaning electron micrscopy and to development of floral calendar of the region. First part deals with pollen analysis of 64 honey samples collected from 37 different localities of Pakistan using Light microscopy (LM) and Field Emission Scanning Electron Microscope (FESEM). In this study wide variety of plants foraged by honey bees Apis mellifera, A. cerana, A. dorsata were identified representing the potential for bee keeping of region. In total of 60 different pollen types belonging to 35 families were identified up to species, genetic and family level. It is reported that the most of the plants belong to angiosperm families whereas only one species belong to gymnosperm group.The dominant families belonging to angiosprm includes Brassicaceae, Rosaceae, Rutaceae, Apiaceae, Lamiaceae, Boraginaceae, Mimosaceae whereas the pinaceae is the only one gymnospermic family. In second part, Upright fluorescence microscopy was carried out to identify 12 samples of allergenic pollen from Pakistan. Pollen focal series has been capture at different dimensions expressing the diverse features of pollen, significant for aerobiological sampling identification. Pollen features studied includes pollen morphology, size, shape, exine structure, exine thickness etc. Diverse pollen morphology observed during study may appear confusing when working on airborne pollen as many pollen show similarity in shape. Third part deals with Field emission scanning electron microscopy (FESEM) of pollen grain. Finding of this analyses shows that the external morphological features of pollen (sculpturing) were useful for identification of different taxa. Honey pollen were identified using morphological features, number and arrangement of pore and colpi, size and shape. In this study 49 pollen grains types belonging to 25 families were reported. It is noted that the shape and sculpturing of pollen ranging from psilate, scabrate to reticulate, bireticulate and echinolophate. Survey of allergenic and melliferous flora was carried out side by side to keep the record about allergenic and bee floral preference of specific sites through surveys and interviews and recording their flowering time and distribution. In total of 205 plant species were identified belonging to sixty seven families. The wild plant species like Justicia adhatoda Linn., Acacia nilotica (L.) Delile, Ziziphus jujuba Mill etc. may serve in apiculture industries at large scale while the species like Taraxicum officinalis L., Artemisia dubia Wall., Casuarina equisetifolia L., Broussonetia papyrifera (L.) L’Herit., Cupressus sempervirens L., or Pinus roxburghii Sargent, playing role in triggering pollen allergy symptoms. Cultivated crops like Pennisetum, Nigella sativa, Triticum sativum along with fruit gardens of Pyrus spp., Prunus spp., Eryobotria japonica, Citrus spp. etc. are popular melliferous flora of studied sites. Exotic/ introduced species like Eucalyptus globulus or Parthenium hysterophorus, are also frequently visited by bees indicating the significance of those plants in bee industry and at the same time triggering the allergies by the windborne pollen. Overall results are based on pollen features like morphology and sculpturing. It is concluded that different microscopic analysis techniques gives more clear and authentic picture of allergenic and melliferous pollen identification which is well supported by floral calendar. Diversity of pollen are observed in case of melliferous pollen and most of the allergenic pollen were found less sculptured or psilate expressing the adaptation to the specific mode of pollination. The study recommends to compile the pollen book on pollen spectra of Pakistan that could serve as a reference for future studies particularly and at global perspectives generally.