North American Fruit Explorers mailing list at ibiblio

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

----------
From: ARS News Service <NewsService@ars.usda.gov>
Reply-To: ARS News Service <NewsService@ars.usda.gov>
Date: Fri, 27 Feb 2004 09:20:39 -0500
To: ARS News subscriber <lonrom@hevanet.com>
Subject: Raspberries' Year-Round Protective Light Show

STORY LEAD:
Raspberries' Year-Round Protective Light Show
___________________________________________

ARS News Service
Agricultural Research Service, USDA
Don Comis, (301) 504-1625, comis@ars.usda.gov
February 27, 2004
___________________________________________

Raspberries are playing enough tricks with light to suggest they are
likely doing this to hide themselves from insects and deer, as well as
protect themselves against disease, ultraviolet rays, oxidation and
dehydration in freezing weather, according to a soil scientist with the
Agricultural Research Service.

Charles M. Feldhake, at ARS' Appalachian Farming Systems Research
Center in Beaver, W.Va., used a special light sphere and fiber optic
probe connected to a spectroradiometer to measure light reflected by
wild black raspberries and an old variety of red raspberry growing along
the edge of a row of scarlet oaks. It's part of Feldhake's research in
agroforestry, the science of interspersing livestock and farm crops with
trees and shrubs.

Feldhake is studying raspberries as one of many possible
"pick-your-own" crops for Appalachian farmers to plant at the edge of
trees that might be grown for firewood, for example. He found that the
fuzzy "white" undersides of raspberry leaves were highly reflective,
about a third as much as a pure-white surface. In deserts, it's the
upper sides of plant leaves that normally are reflective, to keep the
plant from overheating.

But raspberries grow well under partially shaded, moist conditions, so
the light-reflecting fuzziness on the leaves' undersides seems instead
designed to hide the plant from insects that expect plant leaves to be
green. It also repels water, helping prevent moisture from spreading
plant diseases, as well as keeping the leaf stomata free of moisture and
open for the gas exchange required for photosynthesis.

The "cane" stems of raspberries turn from green to red in the winter,
offering protection against ultraviolet rays and oxidation. A white,
waxy coating on the canes should help the plant blend in with snow and
hide itself from deer when it is some of the only browsing food above
the snow. The cane coating reflected nearly half as much light as a
white surface. 

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

* This is one of the news reports that ARS Information distributes to
subscribers on weekdays.
* Start, stop or change an e-mail subscription at
www.ars.usda.gov/is/pr/subscribe.htm
* NewsService@ars.usda.gov | www.ars.usda.gov/news
* Phone (301) 504-1638 | fax (301) 504-1648