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Volume 26, Number 16
22 August 2007

pp 3729-3878

Asterisk hairs of olive tree leaves - Olive trees (Olea europaea) are a common sight in arid climates, especially around the Mediterranean Sea. They grow very slowly but can be exceptionally long-lived, sometimes up to 2000 years. The lower surfaces of their leaves are covered with a dense carpet of umbrella-like silvery structures, called trichomes, which protect the vitally important stomates from excess photons, UV-B radiation, wind and stomatal clogging induced by occasional salt spray. Trichomes also contribute to minimizing evaporation by absorbing part of the water that is lost during transpiration. Therefore they substantially help olive trees to withstand the elements - often successfully over many centuries. The colored scanning-electron-microscopy (SEM) image on the cover is shown at approximately 1,300x magnification. The original SEM scan was produced at the Pr�ftechnik Uri GmbH, Switzerland, and the copyright belongs to Martin Oeggerli, 2007. Please find many other high-quality SEM pictures from the hidden microcosmos in full color at: www.micronaut.ch

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