Hay Fever Gallery

Hazel pollen grains

Hazel pollen grains. Coloured scanning electron micrograph (SEM) of pollen grains from the Hazel tree, Corylus avellana. These microspores are shed from male catkins (hanging pollen-bearing structures) on the Hazel tree, released into the air and carried by wind to pollinate the female flowers. Pollen grain shape, size and surface sculpturing varies greatly between species, and may be used by botanists to identify plants from pollen grains. Large quantities of Hazel pollen occur as a fine yellow mist at springtime in parts of Europe, and may contribute to attacks of hay fever (allergic rhinitis). Magnification: x1, 730 at 5x7cm size

© POWER AND SYRED/SCIENCE PHOTO LIBRARY

Coloured SEM of sunflower pollen grains

Pollen grains. Coloured Scanning Electron Micro- graph of pollen grains of the sunflower, Helianthus annuus. Pollen grain size, shape and surface texture differ from one plant species to another. The outer walls (exine) of these pollen grains are covered with spikes which allow them to catch on the bodies of insects, aiding cross- pollination. The form of the pollen grain wall is also used by botanists to identify plant species. Pores in the pollen wall help in water regulation and germination. Pollen grains contain the plant's male gametes which fertilise the female egg (ovule) to produce a seed. Pollen also causes hay fever. Magnification: x1, 125 at 5x7cm size. x3, 800 at 10x8ins

© POWER AND SYRED/SCIENCE PHOTO LIBRARY

Pollen grain of Cocksfoot grass

False colour scanning electron micrograph (SEM) of a pollen grain from cocksfoot grass, Dactylis glomerata, showing a germinating pore from which a pollen tube emerges. Cocksfoot pollen, a summer grass pollen dispersed by the wind, is a major cause of hay fever (medical term Allergic rhinitis & pollenosis). Sufferers produce a sensitising antibody, immunoglobin E (IgE), which attaches to cells in the nose & eyes. It reacts with inhaled pollen causing the release of various chemicals including histamine. Histamine causes the mucous membranes of the nose, eyes & throat to swell & become inflamed, bringing on the familiar symptoms of hay fever. Magnification: X 530 at 35mm size. original is bw print B786/077

© DR JEREMY BURGESS/SCIENCE PHOTO LIBRARY