* High CO2 levels hamper nitrate incorporation by plants
* Hothouse tomatoes challenging field-grown varieties
* UC Davis tops in ag and environment publications, citations
* New UC ag and natural resources Web site launched
* Media calendar:
-- Livestock forum
-- Pest control conference
HIGH CO2 LEVELS HAMPER NITRATE INCORPORATION BY PLANTS
Rising levels of atmospheric carbon dioxide that are
associated with global warming can interfere with plants'
ability to incorporate certain forms of nitrogen,
dramatically altering plant life worldwide and forcing
significant changes in agricultural fertilizer use, according
to a plant physiologist at the University of California,
Davis.
These findings are reported by lead author Arnold Bloom and
colleagues in the Feb. 5 issue of the Proceedings of the
National Academy of Sciences.
"It's been known for some time that increased concentrations
of carbon dioxide in the atmosphere initially boost carbon
intake and growth in plants but eventually the accelerated
carbon assimilation declines," said Bloom, a professor in the
UC Davis vegetable crops department. "The results from our
study indicate that carbon dioxide inhibition of nitrate
assimilation contributes to this phenomenon and suggest two
physiological mechanisms that may be responsible."
In this newly published study, the UC Davis researchers
discovered that nitrate fertilizer is not nearly as efficient
as ammonium fertilizer when atmospheric carbon dioxide levels
are unusually high. In laboratory experiments they grew wheat
seedlings with either nitrate or ammonium under varying
concentrations of atmospheric carbon dioxide. They discovered
that elevated levels of carbon dioxide inhibited the
processing of nitrate in the wheat leaves in two ways.
First, plants place a higher priority on storing and
processing carbon dioxide than they do nitrogen, so when
carbon dioxide levels rose, some of the chemicals needed to
assimilate the nitrate were already tied up in assimilating
carbon dioxide.
Second, to make use of nitrate, the plants have to convert
nitrate into nitrite and then move the nitrite into
structures within their cells called chloroplasts, which are
the center for photosynthesis. Bloom's research indicated
that elevated levels of carbon dioxide interfered with the
overall process of photosynthesis by blocking this vital
transfer of nitrite into the chloroplasts.
Media contacts: Arnold Bloom, Vegetable Crops, (530) 752-
1743, ajbloom@ucdavis.edu; Patricia Bailey, News Service,
(530) 752-9843, pjbailey@ucdavis.edu.
HOTHOUSE TOMATO INDUSTRY CHALLENGES CALIFORNIA'S
FRESH-TOMATO SECTOR
U.S. consumers are eating more and more fresh tomatoes, but
producers of domestic field-grown tomatoes are smarting from
increasing competition from hothouse tomatoes grown both here
and abroad, according to a UC Davis agricultural economist.
"As a result, we're seeing increased tensions in
international trade relationships centered around the tomato
industry," said Roberta Cook, a UC Cooperative Extension
economist in the UC Davis agricultural and resource economics
department. She noted that three tomato-related lawsuits are
now in the courts involving the United States, Mexico and
Canada -- all three partners in the North American Free Trade
Agreement (NAFTA).
Per capita tomato consumption in the United States has
climbed from 16.5 pounds in 1994-95 to 19.1 pounds in 2000,
according to Cook. But that rising demand has been partly
served by hothouse, rather than field-grown, tomatoes
produced in all three NAFTA countries. Hothouse tomatoes now
represent about 12 percent of all fresh tomatoes consumed in
the United States and nearly one-fourth of the retail fresh-
tomato market in the U.S.
Canada led the development of the hothouse tomato industry,
growing fresh-market tomatoes in greenhouses as a way of
coping with a very short growing season. As of 2000, Canada
was producing about 402 million pounds of hothouse tomatoes,
with 56 percent exported to the United States.
The U.S. primarily exports fresh field-grown tomatoes, picked
at the mature green stage, to Canada and Mexico, while
importing fresh vine-ripe and hothouse tomatoes from both
those nations.
Canella indicates that the increasing competition from the
hothouse industry is making the producers and shippers of
field-grown tomatoes in the United States more dependent on
selling their tomatoes to the foodservice market rather than
retail market.
Media contacts: Roberta Cook, Agricultural and Resource
Economics, (530) 752-1531, cook@primal.ucdavis.edu; Patricia
Bailey, News Service, (530) 752-9843, pjbailey@ucdavis.edu.
UC DAVIS LEADS THE NATION FOR AG AND ENVIRONMENT
PUBLICATIONS, CITATIONS
During the past five years, UC Davis was the most published
research university in the nation in the areas of ecology and
environmental sciences, and food science and nutrition,
according to a survey by the private organization, Institute
for Scientific Information.
>From 1996 to 2000, papers published by UC Davis researchers
were referenced in scientific journals covering ecology and
the environment, and food science and nutrition, more than
papers from any other research institution in the nation,
according to the Institute for Scientific Information.
Environmental research at UC Davis takes place in many
schools and colleges including the College of Agricultural
and Environmental Sciences, the Division of Biological
Sciences, College of Engineering, and the schools of law and
veterinary medicine.
In a decade-long survey, UC Davis researchers also led the
nation in agricultural sciences citations. From 1991 to June
2001, 1,520 papers published by UC Davis researchers were
referenced in 10,602 other journal articles. Following UC
Davis in the agricultural sciences were the University of
Wisconsin and Cornell University.
In this 10-year survey, three UC Davis food scientists were
ranked among the top 20 most referenced of more than 1,500
agricultural science researchers. They are Edwin Frankel,
second; Bruce German, 16th; and the late John Kinsella, 17th.
"It is gratifying for our faculty to learn from such a
reputable organization as the ISI that our research programs
in the areas of environmental sciences and ecology,
agriculture, and food science and nutrition are the most
productive university-based programs in the world," said Dean
Neal Van Alfen, College of Agricultural and Environmental
Sciences. "This reaffirms our belief that research in the
college and elsewhere on campus has impact and is a good
investment in advancing the frontiers of knowledge.
Media contact: Patricia Bailey, News Service, (530) 752-9843,
pjbailey@ucdavis.edu.
NEW UC AG AND NATURAL RESOURCES WEB SITE LAUNCHED
A new Web site offering links to information on crop
production, pest management, gardening, 4-H, nutrition and
other topics has been launched by the University of
California's Division of Agriculture and Natural Resources.
The new site, named and located at Ucanr.org, includes
information provided by the university's statewide programs,
county Cooperative Extension offices and the Davis, Berkeley
and Riverside campuses.
It also offers Spanish-language pages that allow Spanish-
readers to navigate these online resources.
A master calendar provides information on county activities
throughout the state, and there also are links from the site
to statewide employment opportunities within Agriculture and
Natural Resources.
Through this site, the public can also obtain pamphlets,
handbooks and production manuals on a variety of subjects.
Media contact: Jeannette Warnert, Web site coordinator,
Agriculture and Natural Resources, (559) 241-7514,
jeannette.warnert@ucop.edu.
MEDIA CALENDAR: LIVESTOCK FORUM
Feb. 26, Tuesday -- Beef cattle producers will gather for the
50th annual Oakdale Livestock Forum, organized by the
University of California Cooperative Extension. This year's
forum will include speakers addressing a variety of topics
including biosecurity, animal health, nutrition and
supplementation and high-tech carcass analysis. There also
will be a special focus on the relationships between growth,
carcass value and marketing. The forum will be held from 9:30
a.m. to 3:30 p.m. in the Oakdale Community Center in the
Stanislaus County town of Oakdale. Contacts: Jim Oltjen,
Cooperative Extension specialist in the UC Davis animal
science department, (530) 752-5650, jwoltjen@ucdavis.edu;
John Stumbos, Agricultural and Natural Resources, (530) 754-
9554, jdstumbos@ucdavis.edu.
MEDIA CALENDAR: PEST CONTROL FOR PUBLIC PLACES
March 4-5, Monday and Tuesday -- Methods for reducing
pesticide use in places like school grounds, city gardens and
public parks will be discussed during the Integrated Pest
Management for Public Agencies Conference, sponsored by the
University of California's Integrated Pest Management
Project. The latest research-based practical information on
pest biology will be presented, and conference participants
will be advised on how to develop integrated pest management
strategies for both landscape and buildings. The two-day
meeting will be held in the Buehler Alumni and Visitors
Center at UC Davis. Contacts: Mary Louise Flint, Integrated
Pest Management, (530) 752-7692, mlflint@ucdavis.edu; John
Stumbos, Agricultural and Natural Resources (530) 754-9554,
jdstumbos@ucdavis.edu.