Saturday, August 26, 2006

High Temperatures Could Leave Seed Crops Sterile

Some crop plants--like rice, kidney beans, soybeans and peanuts--stop producing seeds when exposed to high temperatures. Agricultural Research Service (ARS) scientists in Gainesville, Fla., found that the higher temperatures affect reproductive processes in the plants.

Soil scientist L. Hartwell Allen, Jr., and plant physiologist Joseph C. Vu in the ARS Chemistry Research Unit at Gainesville carried out temperature-elevation studies with colleagues associated with the University of Florida-Gainesville and the International Rice Research Institute.Increased temperatures affect reproductive processes more than they affect photosynthesis and vegetative growth, according to Allen.

A plant may still grow to its typical size even if its seed development fails.To evaluate heat tolerance of various cultivars, the scientists used growth chambers under natural sunlight and greenhouses for a range of temperatures. They measured heat’s effect on yields of rice, grain sorghum, kidney beans, soybeans and peanuts grown at two levels of carbon dioxide--350 parts per million (ppm), which is near current levels of atmospheric carbon dioxide, and 700 ppm--and at four maximum/minimum daily temperature cycles.

Each crop was found to have its own optimal mean daily temperature (OMDT) for seed yield. As temperatures rose, yields decreased, dropping to zero at about 18 degrees F above each crop’s specific OMDT. Seed productivity generally decreased by about six percent for every one degree F above a given plant’s OMDT, according to Allen.

For all the crops studied, even when pollination was successful, shortened seed-filling time and higher respiration rates at moderate temperature increases also contributed to yield declines.Using traditional breeding to develop crops with built-in heat tolerance may offer the best hope for helping plants--and growers--cope with rising temperatures, according to Allen.




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AGRI-INFO/AUGUST 26, 2006



TITLE: HIGH TEMPERATURES COULD LEAVE SEED CROPS STERILE

ALAM BA NINYO NA NATUKLASAN NG MGA AGRI-EXPERT NA MALAKI ANG EPEKTO NG HIGH TEMPERATURES O MATATAAS NA TEMPERATURA SA REPRODUCTIVE PROCESS NG MGA HALAMAN?

ITO ANG DAHILAN KUNG BAKIT ANG MGA TANIM TULAD NG PALAY, KIDNEY BEANS, SOYBEANS AT PEANUT AY TUMITIGIL NA SA KANILANG SEED PRODUCTION KAPAG NA-EXPOSE SA HIGH TEMPERATURES.

KAUGNAY NITO, GUMAWA NG KANILANG TEMPERATURE-ELEVATION STUDIES ANG MGA EKSPERTO SA PANGUNGUNA NINA SOIL SCIENTIST L. HARTWELL ALLEN JR AT PLANT PHYSIOLOGIST JOSEPH VU NG ARS CHEMISTRY RESEARCH UNIT, KASAMA ANG MGA EKSPERTO NG UNIVERSITY OF FLORIDA AT INTERNATIONAL RICE RESEARCH INSTITUTE.

AYON KAY ALLEN, ANG MATAAS NA TEMPERATURA AY NAPATUNAYANG MAS NAKAKAAPEKTO NG MALAKI SA REPRODUCTIVE PROCESS KESA SA EPEKTO NITO SA PHOTOSYNTHESIS AT PAGLAKI NG MGA TANIM O HALAMAN.

DAHIL DITO, SADYANG MAHALAGA NA MAISAILALIM SA EBALWASYON ANG HEAT TOLERANCE NG IBAT-IBANG URI NG TANIM, AT KAILANGANG GUMAMIT ANG MGA SIYENTISTA NG TINATAWAG NA GROWTH CHAMBERS SA ILALIM NG NATURAL NA SIKAT NG ARAW AT GREEHOUSE PARA SA PABAGU-BAGONG TEMPERATURA.



http://www.ars.usda.gov/is/AR/archive/aug06/plant0806.htm

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