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Open access

R. R. Romanowski

Abstract

Activated carbon was applied in an anticrustant mixture with direct-seeded tomatoes (Lycopersicon esculentum Mill.) to protect them from diphenamid (N, N-dimethyl-2,2-diphenylacetamide) and metribuzin [4-amino-6-tert-butyl-3(methylthio)-as-triazin-5(4-H)-one] injury. Commercially acceptable weed control and increased crop safety were obtained by the application of activated carbon with both herbicides.

Open access

R. D. William and R. R. Romanowski

Abstract

Nitralin [4-(methylsulfonyl)-2,6-dinitro-N,N-dipropylanaline] severely injured direct seeded tomatoes that were covered with soil or expanded vermiculite in the greenhouse and field. Powdered activated carbon increased the adsorptive capacity of a vermiculite anticrustant mixture and protected tomato and weed seedlings. A dequate seedling protection was obtained by spraying a 2-inch wide band of activated carbon over seedling furrows filled with vermiculite. Mechanical application of an activated carbon vermiculite mixture in 1-inch circular clumps protected tomato seedlings and protected fewer weeds than the 2-inch spray band. Granular carbons reduced soil crusting and protected seedlings from preemergence herbicides.

Open access

H. P. Wilson, B. Graves, and C. P. Savage Jr.

Abstract

Incorporation of S-propyl dipropythiocarbamate (vernolate) to a depth of 5.0 cm in soil resulted in more vigor reduction of sweet potatoes [Ipomoea batatas (L.) Lam.] than incorporation to a depth of 10.0 to 12.5 cm. The initial plant response to vernolate by ‘Nemagold’ was greater than by either ‘Julian’ or ‘Centennial’. Yields of all 3 cultivars were not affected by vernolate at the rate of 2.2 kg/ha, but yields were reduced at rates of 4.5 and 6.7 kg/ha. Activated carbon applied as a suspension in the transplant water protected sweet potatoes from vigor reductions at rates of vernolate up to 6.7 kg/ha. Dipping roots in a suspension of activated carbon prior to transplanting failed to protect sweet potatoes from vernolate injury.

Open access

G. C. Sharples

Abstract

Activated carbon stimulated seed germination of lettuce (Lactuca sativa L.) in soil and vermiculite. Stimulation was strongly dependent upon the moisture potential. Germinating seeds were shown to excrete an inhibitor into the micro-environment which cannot diffuse away rapidly at moisture potentials near the soil field capacity or at analogous potentials in vermiculite. Increasing the moisture potential or adding activated carbon caused rapid removal of inhibitor from the seed micro-environment.

Open access

Sangho Jeon, Charles S. Krasnow, Gemini D. Bhalsod, Blair R. Harlan, Mary K. Hausbeck, Steven I. Safferman, and Wei Zhang

a holding tank, as shown in Fig. 1 . The filter unit was designed as shown in Fig. 2 and was packed with either sand [99.69% silica (Granusil; Unimin Corp., New Canaan, CT)] or activated carbon [AC (Filtrasorb 300; Calgon Carbon Corp., Moon

Free access

Dorm G. Shilling, Joan A. Dusky, Mark A. Mossier, and Thomas A. Bewick

Poor emergence of commercially grown lettuce has been observed when planted immediately after the removal of a celery crop. Greenhouse experiments were conducted to evaluate the possible allelopathic effects of celery residue on the emergence and growth of lettuce. The influence of amount and type of celery tissue, growth medium and fertility, incubation time in soil, and amendment of growth medium containing celery residue with activated charcoal was evaluated with respect to the allelopathic potential of celery. Celery root tissue was 1.8 and 1.6 times more toxic to lettuce seedling growth than was celery petiole or lamina tissue, respectively. Lettuce shoot growth was inhibited to a greater extent when grown in sand amended with celery residue rather than either amended vermiculite or potting soil. Incubation of celery root residue in soil for 4 weeks increased phytotoxicity at 1% (v/v) and decreased it at 4% (v/v). Increasing the fertility of pure sand with varying amounts of Hoagland's solution did not reverse the allelopathic effects of celery residue. The addition of activated carbon to the medium increased the growth of lettuce exposed to celery residues. Celery residues possess allelopathic potential to developing lettuce seedlings. Celery tissue type and concentration, soil type, incubation of celery root residue in soil, and addition of activated carbon to the growing medium influenced the magnitude of the observed phytotoxicity.

Free access

Joseph C. Neal, Marvin P. Pritts, and Andrew F. Senesac

Five greenhouse and two Geld experiments were conducted to evaluate tissue culture-propagated (TC) raspberry (Rubus idaeus cv. Heritage) sensitivity to preemergent herbicides. Plant performance was measured by plant vigor, above-ground fresh weight, root development, and primocane number. Simazine and oryzalin caused significant injury to newly planted TC raspberry plants in greenhouse and field experiments. The severity of injury was generally linear with respect to herbicide rate, but no appreciable differences in injury were observed between the granular and spray applications. Napropamide wettable powder caused some foliar injury, but plants recovered within one growing season and growth was equal or superior to the hand-weeded controls. The granular formulation of napropamide produced similar results, but did not cause the initial foliar burn. Pre-plant dipping of roots into a slurry of activated carbon did not prevent simazine or oryzalin injury, but injury was reduced when herbicide applications were delayed. Simazine applied 4 weeks after planting was not Injurious, and oqzalin applied 2 or 4 weeks after planting caused some foliar injury, hut no reduction in plant fresh weight. Delayed treatments of napropamide increased foliar injury. Herbicide tolerance of tissue-cultured plantlets appeared to be less than that of conventionally propagated plants. Chemical names used: N,N-diethyl-2-(1-napthalenyloxy)propanamide (napropamide), 4-(dipropylamino)-3,5-dinitrobenzenesulfonamide (oryzalin), 6-chloro-N,N'diethyl-1,3,5-triazine-2,4-diamine (simazine).

Open access

Wilson R. Maluf and Edward C. Tigchelaar

Abstract

Factors contributing to genetic differences in low temperature seed germination of tomato (Lycopersicon esculentum Mill.) were examined by comparing the cold germinating (CG) accession PI 341985 the non-cold germinating (NCG) ‘Centennial’ and random F4 lines with varying low temperature germinating abilities. Rate of radicle elongation at 10°C was similar for both parental genotypes indicating that differences in emergence at 10° are not due to growth rates, but rather to more rapid initiation of germination activities in CG. Preincubation of seeds in hypertonic salt solutions enhanced rate of germination at 10°C equally in both lines, but did not substitute for the genetically based cold germinating ability. Low temperature germinating ability is associated with sprouting at high osmotic concentrations, and with a several fold higher rate of increase in peroxidase activity during the first 10 days of incubation at 10°. Germination at 10° of the NCG lines is improved by activated carbon in the germination media whereas no enhancement occurred in CG lines. Inhibition and/or delay in germination at 10° in NCG lines is due, in part, to low temperature induced formation of activated carbon adsorbable inhibitors of seed germination.

Open access

W. R. Maluf and E. C. Tigchelaar

Abstract

Seed germination at 10°C in partially isogenic F5 lines of tomato (Lycopersicon esculentum Mill.) with varying low-temperature germinating abilities was negatively correlated with oleic acid levels and positively correlated with linoleic acid contents. Fatty acid composition did not change with time of incubation at 10°C, nor in the presence of activated carbon. Fatty acid composition of membrane-lipid fractions was similar to the total fatty acid of the seeds. The proportion by which linoleic acid is higher in cold-germinating lines (CG) is roughly the same as the amount by which oleic acid is lower in non-cold-germinating (NCG) lines. We suggest that gene regulation of cold-germinating ability is associated with a more extensive desaturation of oleic acid into linoleic acid during seed development.

Full access

N. Lallu, J. Burdon, D. Billing, D. Burmeister, C. Yearsley, S. Osman, M. Wang, A. Gunson, and H. Young

There are three main systems for the removal of carbon dioxide (CO2) from controlled atmosphere (CA) stores: activated carbon (AC) scrubber, hydrated lime scrubber, and nitrogen (N2) flushing. Each system is likely to have a different effect on the accumulation of volatiles other than CO2 in the store atmosphere, and these volatiles may influence the storage performance of the produce. `Hayward' kiwifruit (Actinidia deliciosa) were stored at 0 °C (32.0 °F) under 2% oxygen (O2) and 5% CO2 in CA rooms fitted with one of the three systems. In a fourth CA room, fruit were stored at 0 °C under air conditions. All four stores had their atmosphere scrubbed for ethylene. The store atmospheres and fruit firmness were monitored at intervals up to 27 or 14 weeks of storage in the 1999 or 2000 season, respectively. At the end of CA storage, and after an additional 4 weeks of air storage at 0 °C, fruit were evaluated for rots and physiological pitting. Linear discriminant analysis (LDA) showed the three CO2 removal systems altered the volatile profiles of the store atmospheres differently. CA storage delayed fruit softening markedly, and once returned to air, softening resumed at a rate equivalent to that of fruit of equivalent firmness that had not been CA stored. There was little effect of CO2 removal system on the fruit softening during storage. Although CA storage resulted in a higher incidence of rots, there was little difference among CO2 removal systems compared to the main effect between air and CA storage. Similarly, CA storage delayed the appearance of physiological pitting, although the incidence increased rapidly during an additional 4 weeks of storage in air, and was higher than for fruit stored throughout in air. Among the CO2 removal systems, N2 flushing resulted in fruit with the lowest incidence of physiological pitting. It is concluded that different CO2 removal systems alter room volatile profiles but may not consistently affect the quality of `Hayward' kiwifruit during CA storage.