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["Lon J. Rombough" <lonrom@hevanet.com>]

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From: ARS News Service <NewsService@ars.usda.gov>
Reply-To: ARS News Service <NewsService@ars.usda.gov>
Date: Tue, 30 Mar 2004 08:29:24 -0500
To: ARS News subscriber <lonrom@hevanet.com>
Subject: "Opportunistic" Plant Roots May Have Untapped Potential

STORY LEAD:
Plant Roots, Too, Know How to "Seize the Moment"
___________________________________________

ARS News Service
Agricultural Research Service, USDA
Don Comis, (301) 504-1625, comis@ars.usda.gov
March 30, 2004
___________________________________________

A recent discovery by Agricultural Research Service plant physiologist
Richard Zobel may lead to a "rewriting of the book" on plant roots.
Zobel and a colleague have found that many plant roots commonly regrow
from the same spot on a root, and that they can do this on roots deep
below the soil surface.

Zobel, with the ARS Appalachian Farming Systems Research Center in
Beaver, W.Va., and Dominick J. Paolillo, Jr., at Cornell University in
Ithaca, N.Y., found evidence of roots growing this way on 22 species of
plants from 12 different plant families in nine orders of plants. These
plants included alfalfa, carrots, chicory, clover, crown vetch,
dandelion, horse chestnut, lamb's-quarters, parsnip, poke weed, rock
maple, thistle and tree of heaven.

Zobel and Paolillo made these discoveries while searching for plants
with so-called opportunistic, or adventitious, rooting. They found
adventitious roots growing in clusters along older roots. Adventitious
roots grow from a different cell layer than the regular, lateral roots,
so a plant that has used up the tissue available to grow regular roots
can still grow adventitious roots.

These roots are called "opportunistic" because they can develop in a
matter of hours, to take advantage of sudden environmental changes such
as a rare rain in a desert.

The discovery that adventitious roots growing this way are an everyday
occurrence suggests they may play an important and unexpected role in
routinely helping plants reach water and nutrients. These roots can
sprout on larger roots whose lateral roots have long since died back,
enabling the plant to access water and nutrients that have recently
become available in those sections of the soil that would otherwise be
out of reach. 

This information could also help scientists introduce adventitious
roots to a crop like cotton that apparently is one of the few plants
that doesn't have them, as a more efficient way for the crop to grow new
roots when rain comes after a dry spell.

ARS is the U.S. Department of Agriculture's chief scientific research
agency.
___________________________________________

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