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  • Author or Editor: D. L. Berry x
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Abstract

Plants grown in dichloropropene (a soil fumigant) treated soil have significantly higher than usual carotenoid levels. Treatments with dichloropropenes, 3-chloroallyl alcohol, 3-chloropropionic acid, 3-hydroxypropionic acid, 3-chloro-l-propanol and malonic acid decreased the incorporation of β-hydroxy-β-methylglutaric acid and mevalonic acid into carotenoids of etiolated maize. Lipoxidase in tomato was inhibited by much lower concentrations of these compounds than were required to inhibit the incorporation of β-hydroxy-β-methylglutaric acid or mevalonic acid. This difference could account for the eventual increase in the total carotenoids in the plant.

Open Access

Abstract

Labeled 1,3-dichloropropene (1,3-DCPE) (5.90 × 10−7 moles/ml) or 3-chloroallyl alcohol (3-CAA) (6.12 × 10−7 moles/ml) was administered to tomato seedlings through the roots. Radioactivity in various fractions was determined at various intervals of time. Maximum amounts of 1,3-DCPE and 3-CAA had been absorbed and translocated to the aerial parts of the plants by 4 hr. Gas chromatographic analysis of plant materials showed that the compounds were readily metabolized by the plant. The 1,3-DCPE was metabolized to 3-CAA, part of which was converted to 3-chloroacrylic acid and 3-chloro-1-propanol as confirmed by co-chromatography with standard compounds. No parent 1,3-DCPE was found in the plant after a 72-hr incubation period and 3-CAA was not detected after a 96-hr incubation. In unlabeled experiments, micrographs of cells from control plants showed normal organellar structure. By contrast, the chloroplasts in some leaf cells from plants treated with 3-CAA had undergone slight swelling and partial disruption of the membrane system 6 hr after treatment. At 12 and 24 hr after treatment, both chemicals had disrupted the organellar structure of the chloroplasts and the rough endoplasmic reticulum (RER) of some cells. Although the normal organellar structure was disrupted, the data indicate that the dichloropropenes and 3-CAA do not present plant residue problems, and that concern about the ultimate environmental fate of these compounds may be minimal.

Open Access

Greenhouse experiments were conducted in 2005 and 2006 near Live Oak, FL, to develop fertilization programs for fresh-cut ‘Nufar’ basil (Ocimum basilicum) and spearmint (Mentha spicata) in troughs with soilless media using inputs compliant with the U.S. Department of Agriculture's National Organic Program (NOP). Four NOP-compliant fertilizer treatments were evaluated in comparison with a conventional control. Treatments and their analyses in nitrogen (N), phosphorus (P), and potassium (K) contents are as follows: conventional hydroponic nutrient solution [HNS (150 ppm N, 50 ppm P, and 200 ppm K)], granular poultry (GP) litter (4N–0.9P–2.5K), granular composite [GC (4N–0.9P–3.3K)], granular meal [GM (8N–2.2P–4.1K)], and GM plus a sidedress application of 5N–0.9P–1.7K fish emulsion (GM + FE). Electrical conductivity (EC) of the media, fresh petiole sap nitrate (NO3-N) and K concentrations, dried whole leaf NO3-N, P, and K concentrations, and yield and postharvest quality of harvested herbs were evaluated in response to the treatments. Basil yield was similar with HNS (340 g/plant) and GP (325 g/plant) in 2005 and greatest with HNS (417 g/plant) in 2006. Spearmint yield was similar with all treatments in 2005. In 2006, spearmint yields were similar with the HNS and GP yields (172 and 189 g/plant, respectively) and greater than the yields with the remaining treatments. In both years and crops, media EC values were generally greater with the GC than with the GP, GM, and GM + FE treatments but not in all cases and ranged from 1.77 to 0.55 dS·m−1 during the experiments. Furthermore, HNS media EC values were consistently equal to or lower than the GP media EC values except with EC measurements on 106 days after transplanting in both crops in 2005. Petiole NO3-N and K results were variable among crops and years, but provided valuable insight into the EC and yield data. We expected EC, petiole NO3-N, and petiole K to be consistently higher with HNS than with organic treatments, but they were not, indicating a reasonable synchrony of nutrient availability and crop demand among the organic treatments. The postharvest quality of both basil and spearmint was excellent with all treatments with few exceptions.

Full access

Abstract

Six strains of bacterial canker (Clavibacter michiganensis ssp. michiganensis), isolated from tomato plants from greenhouses or fields near Cleveland, Ohio, were tested for virulence. The most virulent of the strains was used to evaluate 13 cultivars reported to be resistant to bacterial canker. Eleven of the cultivars were resistant at a high inoculum level (8.5 × 108 cells per plant) and the other two only at a lower level (8.5 × 102 cells per plant). It was demonstrated that it is possible to identify plants with intermediate resistance using a dilute inoculum of a virulent strain of C. michiganensis

Open Access

The maintenance of pH in unbuffered nutrient solutions has important consequences for the hydroponic industry and proposed nutrient delivery systems for plants in space. The requirement for charge balance by a model plant system, dwarf wheat (Triticum aestinum cv. Yecora rojo), is largely a function of the uptake ratio of four cation species ( NH 4 + , Ca2+, and Mg2+) and two anion species ( NO 3 and SO 4 2 ) up to anthesis. The change in electrical conductivity (EC) and pH of the nutrient solution over time integrates the overall influx:efflux process of the plants. Solutions with three different NH4:NO3 ratios were sampled at 15-min intervals over a 12-h period at 9, 10, 16, 17, 23, 24, 37, and 38 days after planting. Exhaustion of N in the solution at all stages of ontogeny resulted in a 2- to 3-fold reduction in ΔpH/Δt, despite high plant tissue N and irrespective of the concentration of other charge balance ions in solution. These data, combined with a plant nutrient uptake database (normalized for plant relative growth rate per mole PPF), suggest that a system can be developed to control pH by direct supply of various alternative nutrient stock solutions, rather than by the addition of H+ or OH from acid or base.

Free access

Abstract

Asparagus (Asparagus officialis L.) cv. UC 157 planted in desert coarse sand in the fall of 1979 and harvested in the springs of 1981, 1982, and 1983 was irrigated with geothermal water, with 2240 ± 1290 ppm total dissolved solids and ground water 1430 ± 460 ppm total dissolved solids. Yields of 3.1 MT/ha of large spears were obtained with ground water and 0.03 MT/ha with the geothermal-irrigated asparagus. Na and Li were significantly increased in the spears that received geothermal irrigation, and B and Fe were significantly increased in those irrigated with ground water. Toxic accumulation of elements in the spears did not occur when geothermal water was used for irrigation, but yields were reduced.

Open Access

Shoot regeneration from apple (Malus domestica Borkh.) leaf explants following particle bombardment at various acceleration pressures was studied. Basal leaf segments of micropropagated `Royal Gala' apple were bombarded with 1 μm gold particles, accelerated using helium pressures of 4.5, 6.2, 7.6, 9.3, or 13.8 MPa (650–2000 psi), and cultured on shoot regeneration medium consisting of N6 salts supplemented with 10 μM TDZ for 5, 10, or 20 days in darkness. Bombarded and control explants exhibited 63% to 100% shoot regeneration. With a 5-day dark period, average shoot production per explant ranged from 6.1 to 14; bombardments of 4.5 and 6.2 MPa significantly increased shoot production over the controls. With a 10-day dark period, average shoot production per explant ranged from 9.1 to 22 following bombardment at 9.3 and 6.2 MPa, respectively. Following bombardment at 6.2 MPa, 75% of the explants produced more than 20 regenerants per explant. With a 20-day dark period, average shoot production per explant ranged from 8.9 to 19 following bombardment at 13.8 MPa and following no bombardment, respectively. Shoot production per explant was significantly less than the controls following bombardments ranging from 6.2 to 13.8 MPa. Shoot production was highest per explant with particle bombardment at 6.2 MPa followed by incubation in darkness for 10 days. Chemical name used: thidiazuron (TDZ).

Free access

Maintaining pH to optimize nutrient availability in unbuffered nutrient solutions is important for closed spaceflight hydroponic systems and in agriculture. Total nutrient uptake is reflected by electrical conductivity (EC) measurements, while pH reflects the net imbalance of cation and anion absorption. The pH of nitrate-only (0 NH 4 + : 100 NO 3 ) nutrient solutions normally increases, whereas with equimolar (50 NH 4 + : 50 NO 3 ), solutions, pH decreases. However, when solution pH was controlled to 5.8 by a mixed N sources (25 NH 4 + : 75 NO 3 ), plant yields of semi-dwarf wheat (Triticum aestivum cv. `Yecora Rojo') were equal to the control (0 NH 4 + : 100 NO 3 ) system. When nutrient uptake was monitored at 15-min intervals, it was found that NH 4 + and NO 3 were taken up simultaneously. Uptake of NH 4 + was more rapid than NO 3 . The change in pH and EC was primarily a function of the absorption of three ions, namely NH 4 + , NO 3 , and K+. A significant amount of the K+ uptake was highly correlated (P < 0.001) to the presence of NO 3 in solution. When the daily N requirement was supplied as a 25 NH 4 + : 75 NO 3 mixture, comparatively little change in solution pH occurred, with reduced K+ uptake by the plants. Thus, by knowing the daily crop N requirement from the relative growth rate, the pH fluctuations within hydroponic nutrient solutions can be reduced with daily additions of a balanced nutrient solution with a 25 NH 4 + : 75 NO 3 mixture of N.

Free access

Particle bombardment has been shown to be useful for genetic manipulation of many plants; however, a critical component for successful transformation is the ability of transformed cells to regenerate plants. This study describes factors that affect the regeneration efficiency of apple leaf explants following particle bombardment. Basal leaf segments of micropropagated `Royal Gala' apple were treated with 1μm gold particles (0.5 μg/10μl), accelerated at either 4.5, 6.2, 7.6, 9.3 or 13.8 MPa, and cultured on N6 salts + l0μM TDZ regeneration medium for 5, 10 or 20 days in the dark. Both microprojectile-treated and control explants exhibited 85-100% regeneration. However, only 30-60% of the explants bombarded at 7.6, 9.3 and 13.8 MPa had more than 10 regenerants and 6-10% had more than 20 regenerants, whereas for control explants and those bombarded at 4.5 and 6.2 MPa, 70-90% had more than 10 regenerants and 30-50% had more than 20.

Free access