Palynological and Morphological Variations in Allergenic Wild Plants

Background and Objective: Airborne pollen grains became from the most important causative of respiratory allergy within both children and adults. The objective of this study is to investigate the palyno-morphological characteristics of selected allergenic wild plant species with a focus on identifying variations in pollen size, shape, aperture type, exine ornamentation and other diagnostic features. Materials and Methods: Flowers and flower buds of twelve species known as causatives of respiratory allergy worldwide were collected from Alexandria Roads, Egypt. These species are perennials with different life forms, three herbs, seven angiosperm and two gymnosperm trees. The pollen grains were acetolyzed and examined by light microscope, while non acetolyzed pollen grains were sputtered onto Aluminum stubs coated with Gold, examined and photographed using a Scanning Electron Microscope. Results: The data obtained revealed that all the studied taxa have small size pollen grains with variable types and numbers of apertures varied from the pantoporate, colpate to colporate. The exine was thin tectate with different ornamentation. The mass percentage of the measured element contents, generally low, but the nitrogen contents, which can be indicated to the protein content, varied between the taxa. The high nitrogen contents were Tamarix nilotica, Clerodendron inerme, Amaranthus viridis and Chenopodium murale, while the two gymnosperm trees have low nitrogen contents. Conclusion: The results showed that the studied taxa induce allergy in different degrees, causing severity symptoms. The angiosperm trees and herbs are more allergic than the gymnosperm trees. Allergy is not restricted to certain plant, but it depends on the quantity of pollen grains released by plant in the air beside several environmental factors and personal history.