Several elevated concentrations of CO2 were injected into the root atmosphere to determine the influence of CO2 concentration in the soil on the growth of eggplant (Solanum melongena L.). Elevated CO2 levels in the root atmosphere consistently increased stem diameter while a significant increase in plant total dry weight and leaf area only occurred during long day/warm temperature conditions. Under periods of short days and low light levels, 15% CO2 reduced total dry weight and leaf area. Applications of 14CO2 to the root zone demonstrated that 14C eggplant roots absorb CO2 from the soil environment and translocate labeled compounds into the shoot.
Hexazinone was applied as a soil drench to 1-year-old rooted hardwood cuttings of highbush (Vaccinium corymbosum L.) and rabbiteye (V. ashei Reade) blueberries in a series of greenhouse experiments. No differences in susceptibility to hexazinone were detected among 10 highbush and 3 rabbiteye cultivars growing in a fine sand soil. Two highbush and 2 rabbiteye cultivars were assayed for hexazinone tolerance in low, medium, and high organic matter soil which contained 1.3%, 3.5%, and 49.5% organic matter, respectively. Hexazinone at 1 or 2 kg/ha had no inhibitory effect on blueberry growth in the high organic matter soil, inhibited growth slightly on the medium organic matter soil and caused severe injury in the low organic matter soil. At rates of 4 and 8 kg/ha, injury was severe on the medium and low organic matter soils but very slight on the high organic matter soil.