False colour scanning electron micrograph (SEM) of a pollen grain of Timothy grass, Phelum pratense, also known as cat's-tail. A summer (June-August)

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False colour scanning electron micrograph (SEM) of a pollen grain of Timothy grass, Phelum pratense, also known as cat's-tail. A summer (June-August) grass pollen dispersed by the wind, it is a major cause of hay fever (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: X600 at 35mm size. Original is bw print b786/139.

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Size: 3491px × 5008px
Photo credit: © DR JEREMY BURGESS/SCIENCE PHOTO LIBRARY / Alamy / Afripics
License: Licensed
Model Released: No

Keywords: allergy, botany, cats-tail, fever, germinating, grass, hay, hayfever, nature, phleum, plant, plants, pollen, pore, pratense, reproduction, reproductive, sem, timothy, type