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RESPONSE OF SOLUBLE SUGARS AND STARCH IN FIELD-GROWN COTTON TO OZONE, WATER STRESS AND THEIR COMBINATION
Citation:
Miller, J., R. Patterson, W. Pursley, A. Heagle, AND W. Heck. RESPONSE OF SOLUBLE SUGARS AND STARCH IN FIELD-GROWN COTTON TO OZONE, WATER STRESS AND THEIR COMBINATION. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-94/507.
Description:
Ozone (O3) stress is known to reduce the growth and yield of a number of crops a.nd water stress can modify the extent of the effects. oth O3 and water stress alter the carbohydrate status of plants. ittle is known, however, concerning O3 effects on carbohydrate reserves of field-grown plants, and whether water stress will modify the response to O3. otton (Gossypium hirsutum L. 'McNair-235') plants were exposed to O3 in open-top field chambers for 12 h d-1 throughout the growing season at two levels of soil water (well-watered and water-stressed). he O3 concentrations ranged from 0.021 to 0.073 uL/L-1 (seasonal mean 12 h d-1 concentration). lants were sampled from each plot on four occasions encompassing the early through the late-reproductive stages of growth. oluble sugars (glucose, fructose, and sucrose) and starch were measured in leaves, stems, and roots at each sampling date. here was a tendency for O3 to reduce the concentrations of both soluble carbohydrates and starch and for water stress to cause an increase (with the exception of starch in leaves which decreased). ignificant interactions of the two stresses were not common, but water stress reduced the extent of the O3 effects on starch during late-reproductive growth. he results illustrated that the direction and extent of the response of tissue carbohydrates to O3 and water stress may depend on the extent of development of the stress response and/or the stage of plant growth.