Visit the
Molecular Expressions Website

Galleria
Photo Gallery
Silicon Zoo
Chip Shots
Screen Savers
Museum
Web Resources
Primer
Java Microscopy
Win Wallpaper
Mac Wallpaper
Publications
Custom Photos
Image Use
Contact Us
Search
Home

Reflected Light Digital Image Gallery

White Clover (Trifolium repens)

Known as the white or Dutch clover, Trifolium repens was introduced to North America from Europe as a forage crop and is now commonly found as a weed along pathways, roadsides, and in lawns. In similarity with the other clovers in the Trifolium genus, white clover is an excellent soil builder, particularly for nitrogen-depleted soil.

View a second image of a white clover (Trifolium repens).

Able to reseed itself under favorable conditions, this short-lived perennial clover grows rapidly and spreads vegetatively via stolons. Intolerant of droughty soils, T. repens has a relatively shallow root system. Dutch clover prefers well-drained, fertile soils and cool, moist weather. Soil pH between 6 and 7 is optimal for the plant, and it is highly tolerant of grazing and mowing. Pure stands of white clover are usually not planted because of their low growth habit and low yields. However, when mixed in pastures with grasses, high-quality range and hays are produced because the clover fixes nitrogen for the grasses' usage.

Technically, it is not this member of the pea family (Leguminosae) that actually fixes the nitrogen in the soil, but rather the symbiotic bacteria (Rhizobium species) found living in its root nodules. Visible nodules form when bacteria infect a growing root hair. The mutualistic relationship works well, with the white clover supplying carbon dioxide and other simple carbon compounds to the bacteria, and the bacteria converting atmospheric nitrogen into a form that the plant host can metabolize. The decomposition of roots and leaves of host plants provides soil nitrogen for the surrounding area. Legumes and their symbionts are important because although nitrogen gas is plentiful in the air, it is very stable and rarely combines directly with other atoms. The nitrogen-fixing bacteria convert the gas into ammonia, which is directly taken in by the host's roots. Other species of nitrogen-fixing bacteria exist that are free-living, and that perform the same conversion of nitrogen into ammonia. Still another category of bacteria known as nitrifying bacteria can convert ammonia to nitrates and nitrites, which are assimilated readily by plant roots. The reduced nitrogen compounds are waste products of the nitrifying bacteria, which metabolize ammonia in order to obtain hydrogen that they require for the fixation of carbon.

Contributing Authors

Cynthia D. Kelly, Thomas J. Fellers and Michael W. Davidson - National High Magnetic Field Laboratory, 1800 East Paul Dirac Dr., The Florida State University, Tallahassee, Florida, 32310.


BACK TO THE REFLECTED LIGHT IMAGE GALLERY

BACK TO THE DIGITAL IMAGE GALLERIES

Questions or comments? Send us an email.
© 1995-2022 by Michael W. Davidson and The Florida State University. All Rights Reserved. No images, graphics, software, scripts, or applets may be reproduced or used in any manner without permission from the copyright holders. Use of this website means you agree to all of the Legal Terms and Conditions set forth by the owners.
This website is maintained by our
Graphics & Web Programming Team
in collaboration with Optical Microscopy at the
National High Magnetic Field Laboratory.
Last Modification Friday, Nov 13, 2015 at 02:19 PM
Access Count Since September 17, 2002: 7436
Visit the website of our partner in introductory microscopy education: