Bruno Quebedeaux

Learn More
Abscisic acid (ABA) concentrations and growth rates of developing soybean (Glycine max [L.] Merr. cv. Wye) seeds and pod walls were determined from anthesis to maturation using high pressure liquid chromatographic techniques. Developing soybean seeds contain up to 12,200 ng/g fresh weight of ABA compared to 330 ng/g fresh weight for pod walls. In the(More)
The rates of CO(2) exchange and (14)CO(2) incorporation in the light and dark and the activities of several photosynthetic, photorespiratory, and respiratory enzymes of soybean (Glycine max [L.] Merr. cv. Wye) reproductive structures were determined at weekly intervals from anthesis to pod maturity. At all stages of pod development soybean reproductive(More)
Reproductive as well as vegetative parameters of mature soybean (Glycine max [L.] Merr. cv. Wye) plants grown in chambers in which the aerial portion was exposed to altered pO(2) during all or part of the growth cycle were measured. Oxygen concentration was found to be a key factor controlling all phases of reproductive development. Exposure to 5% O(2) from(More)
Profiles of adenylate and nicotinamide nucleotides in soybean seeds were determined during seed-fill. The ATP content per seed increased during the early seed-filling stages to a level of 10 to 12 micrograms per seed. Seed ATP decreased after 40 days of development and reached its lowest level of less than 1 microgram at maturity. The ATP:ADP ratios were(More)
To examine the impact of projected climate changes on secondary succession, we exposed the same fallow soil with a common seed bank to an in situ gradient of urban to rural macroenvironments that differed in temperature and CO2 concentration ([CO2]). This gradient was established at three locations: Baltimore city center (urban), a city park on the(More)
The potato leafhopper, Empoasca fabae (Harris), is a key pest of alfalfa, Medicago sativa L., in part because of the leafhopper's ability to disrupt upward translocation within phloem tissues. To determine if leafhopper injury also disrupts basal translocation necessary for regrowth and perenniality of alfalfa, we used radiolabeled 14CO2 to measure the(More)
Panicum milioides, a naturally occurring species with reduced photorespiration, P. bisulcatum, a C(3) species, and P. miliaceum, a C(4) species, were grown for 4 weeks at altered pO(2) and pCO(2) and several vegetative growth parameters were determined at weekly intervals. Compared to a pO(2) of 10%, a greater O(2) inhibition of the relative growth rate and(More)
An exponential decay function was fitted with literature data to describe the decrease in corn leaf expansion rate as predawn leaf water potential decreases. The fitted functionwas then applied tomodify an existing leaf area simulation module in a soil–plant–atmosphere continuum corn simulation model (MaizSim) in order to simulate leaf area of corn plants(More)
Dry matter accumulation, nitrogen content and N(2) fixation rates of soybean (Glycine max [L.] Merr. cv. Wye) plants grown in chambers in which the aerial portion was exposed to a pO(2) of 5, 10, 21, or 30% and a pCO(2) of 300 mul CO(2)/l or a pO(2) of 21% and a pCO(2) of 1200 mul CO(2)/l during the complete growth cycle were measured. Total N(2)[C(2)H(2)](More)