Response of Phaseolus vulgaris L. cv. California Dark Red Kidney to 2 different ozone concentration distributions was examined at 2 dose levels in controlled fumigations. When peak ozone concentrations were equal and total doses equivalent, there was no difference in injury, growth, or yield between a simulated ambient distribution with normal diurnal ozone fluctuations and a uniform distribution typical of laboratory fumigation at constant concentration. Plants fumigated with either ambient or uniform ozone distribution had oxidant stipple leaf necrosis and reduced growth and yield. There was significantly increased injury and reduced growth and yield at a high ozone dose for both types of distribution. The data indicate that with equal peak concentration and equivalent total dose, the constant square-wave, ozone concentration distributions in laboratory fumigations are adequate to describe mode of action and magnitude of response to ambient exposures.
effect of different N and K doses applied via drip fertigation on the root distribution of camu-camu plants. The data were analyzed using nondestructive roots images obtained from trenches under the plant canopy. Materials and Methods Our research was
vegetable seedling production: 1) light quality (R/FR ratio) and 2) minimum dose (intensity × duration) requirements to assure the maximum response of rootstock elongation. Incandescent lamps emit light rich in FR (at ≈0.4 to 0.5 R/FR ratio) and are often
Bean plants (Phaseolus vulgaris L. cv. Red Kidney) exposed to ozone with a simulated ambient concentration distribution showed significantly more injury, less growth, and lower yield than those exposed to an equivalent dose of ozone with a uniform concentration distribution. The concentration distribution did not alter the type of biological response of ‘Red Kidney’ beans to ozone, an indication that uniform concentration distribution fumigations are appropriate for investigations of mode of action of pollutants on plants. However, this study suggests that research using a uniform concentration distribution of pollutants may underestimate the magnitude of growth and yield responses to ambient pollutants.
the uptake, distribution, and accumulation of Si in different organs of young olive plants, paying attention to the influence of the dose, the method of application (foliar or soil), and the cultivar. Material and Methods Plant material and
Pollen tube growth of ‘Tilton’ apricot (Prunus armeniaca L.) was reduced by exposure to SO2. An empirical model, based on modified spline functions, described the decrease in pollen tube growth due to increasing dose (hours exposure × concentration of SO2) expressed on logarithmic scale. The response curve, based on this analysis, was “S-shaped” with a decrease from 98.5% pollen tube growth (PTG) for unexposed pollen tubes, based on percent of the style that the longest pollen tubes had grown to 91.6% at ℓ n dose 4.0. These was then a very sharp decrease in PTG to about 45% at ℓn dose 5.7, then a gradual curvilinear response to <1% PTG at the maximum ℓn dose of 7.7. There data strongly indicate that there is a threshold response to SO2 with respect to PTG. Response of ‘Van’ PTG in ‘Napoleon’ sweet cherry (P.avium L.) styles was similar to apricot, but not as definitive because of greater within year variation and differences between years. In one year (1979), a spline function model of PTG in cherry suggested a threshold value at about ℓn dose of 2.1, while in another year (1978), there was a nearly linear decrease in PTG with increasing ℓn dose.
respective salinity levels ranging from 0.9 to 6.5 dS·m –1 ( Table 1 ). Table 1. The emitter combinations for a near-continuous gradient dosing (NCGD) system with eight treatments and the electrical conductivity (EC) of irrigation solution from emitters
al., 1997 ). The Food and Drug Administration (FDA) has approved ionizing radiation dose of up to 1.0 kGy for general fresh fruits and vegetables to control insects and to extend shelf life ( FDA, 2009 ; Olson, 1998 ). Low-dose ionizing irradiation
-Lake et al., 2005a ; Denny and Thornton, 1940 ; Duncan, 1999 ; Prange et al., 1998 ). The effect is dose-dependent, i.e., darkening increases as the concentration rises with saturation of the effect in the range of 1 to 10 μL·L −1 depending on cultivar
, it was hypothesized that a nonionic surfactant applied directly to turfgrass seed would enhance germination and subsequent plant establishment. This hypothesis was tested by applying a low-dose application of surfactant, within a film coating