 EPOD - a service of USRA

The Earth Science Picture of the Day (EPOD) highlights the diverse processes
and phenomena which shape our planet and our lives. EPOD will collect and
archive photos, imagery, graphics, and artwork with short explanatory
captions and links exemplifying features within the Earth system. The
community is invited to contribute digital imagery, short captions and
relevant links.


 Following the Sun

   October 16, 2020

    Sunflower Field

    Sunflowers facing east

   Photographer:  Kathy Arbuckle
   Summary Author:  Kathy Arbuckle

   Late July and August is  sunflower time in eastern Washington State.
   Many  farm fields are filled with the cheerful faces of huge, yellow
   blooms  facing east to greet the Sun each morning. Young sunflowers
   have the ability to  track and follow the Sun as it passes east to
   west, displaying  heliotropism, the  diurnal movement of plants
   in response to the  direction of the Sun.
    Researchers discovered that this is accomplished during the day by
   the plant growing slightly more stem on its east-facing side to cause
   the flower head to gradually face west, while at night it grows a
   longer stem on the west-facing side to return the bud to facing east.
   This cycle is repeated every 24 hours, according to the plant's
   internal  circadian clock.
    Sunflowers stop this mechanism at maturity and from then on set the
   blooming flowers facing east permanently, benefiting the plant's
   ability to attract bees and other  pollinators to their golden,
   sun-warmed flowers. Photos taken on July 20, 2020.

   Photo Details: Top - Camera NIKON COOLPIX P90; Software Nikon Transfer
   1.3 W; Exposure Time 0.0040s (1/250); Aperture ƒ/5.6; ISO equivalent
   64; Focal Length (35mm) 212. Bottom same except - Exposure Time 0.0027s
   (1/366); Aperture ƒ/6.3; Focal Length (35mm) 37
     * Spokane, Washington Coordinates:  47.6588, -117.4260

Related EPODs

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    EPOD 20th - Fence Eating Tree  EPOD 20th - Giant Puffball
    EPOD 20th - Driftwood at La Push, Washington
    More...

Plant Links

     *  Discover Life
     *  Tree Encyclopedia
     *  What are Phytoplankton?
     *  Encyclopedia of Life - What is a Plant?
     *  USDA Plants Database
     *  University of Texas Native Plant Database
     *  Plants in Motion
     *  What Tree is It?

-
   Earth Science Picture of the Day is a service of the  Universities
   Space Research Association.

https://epod.usra.edu
 
