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The effect of postharvest dips on the longevity of Anthurium andraenum cultivar Nitta and Alpinia purpurata was evaluated. The inflorescences were dipped in a 200 ppm benzyladenine (BA) solution, an antitranspirant, or water for 10 minutes. After dipping, anthuriums were placed directly in water and gingers were placed in either water or a 2% sucrose solution and placed in interior conditions (10 μmol m-2s-1 for 12 hr/day, 21±2C). Ginger longevity was increased by 10 days or more by the sucrose solution. The greatest longevity of gingers was obtained when dipped in either BA or the antitranspirant and held in the sucrose solution. Anthurium longevity increased 10 days when dipped in BA, while the other treatments had little effect.

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Abstract

The effects of the plant growth regulators (PGR) gibberellins A4+7 (GA4+7; 25, 50, and 150 mg·liter−1), BA (25 mg·liter−1), and GA4+7 + BA (Promalin; 25 mg·liter−1) on pedicel growth and fruit development of ‘McIntosh’ and ‘Spartan’ apple (Malus domestica Borkh.) trees previously treated with foliar- or soil-applied paclobutrazol (PBZ) were examined. By full bloom, pedicels had completed the elongation growth phase regardless of treatment. Pedicel length was very sensitive to PBZ treatment since it was reduced logarithmically in response to dose. No differences in pedicel diameters were found. PBZ decreased fruit fresh weight, dry weight, and fruit length and diameter in both ‘McIntosh’ and ‘Spartan’ trees. The adverse effects of PBZ carryover on fruit-quality factors such as size and pedicel length were not overcome with GA4+7 (25 or 50 mg·liter−1), BA, or Promalin (25 mg·liter−1) applied when the king-bloom was in full bloom. Reversal of PBZ-induced pedicel length inhibition was only observed with GA4+7 (150 mg·liter−1) applied prior to the main period of pedicel elongation. BA alone had no effect on any fruit growth parameters. PBZ reduced pedicel and fruit cell length, while GA4+7 (150 mg·liter−1) applied at 2 weeks before full bloom increased pedicel cell length. Chemical names used: β-[(4-chIorophenyl)methyl]-α-(1,1-dimethylethyl)-1H-1,2,4-triazol-1-ethanol (paclobutrazol); N-(phenylmethyl)-1H-purine-6-amine (BA); (1α,2β4aα,4bβ,10β)-2,4a,7-trihydroxy-1-methyl-8-methylenegibb-3-ene-l,10-dicarboxylic acid l,4a-lactone (GA4+7).

Open Access

Etiolated seedlings of Pharbitis nil Chois. cv`Violet' were germinated and grown at 24C for 4 days and were then placed in controlled environment chambers (CEC) maintained at 12, 18, 24, 30 or 36C for flower induction. Seedlings were rotated among chambers to result in 25 day/night temperature (DT/NT) treatments. Photoperiod was 8, 12, or 16 hr (250 umols-1 m-2). N-6-benzyladenine (BA) (120 uM) was applied to half the seedlings in each treatment 1hr prior to the inductive night period. After the inductive night period, seedlings were placed in a CEC maintained at 24C under continuous light. Data were collected on percent flowering and flower number at anthesis. Flowering was a function of NT and photoperiod. Flowering increased as night length increased and as NT approached 30C. DT (30C) promoted flowering to a lesser extent than NT. Flowering did not occur on plants grown with a 8hr night length. Flowering occurred on plants grown with a 12hr night length when BA was applied and when plants were grown at 30/24 or 30/30C DT/NT. Seedlings flowered under the 16hr night length when NT was 30C without BA application; flowering occurred with 24 or 30C NT when BA was applied.

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Abstract

A pressure injection method was used with abscisic acid (ABA) and 6-benzylamino purine (BA) to control bud break of one-year-old trees of ‘Yellow Delicious’ apple (Malus domestica Borkh). When dormant trees were injected with 3 ml of 250 ppm (wt/vol) ABA, 58% of buds were inhibited after 28 days compared to 31% of the buds of the controls; injections of 3 ml of 200 ppm (wt/vol) BA above the ABA-injection site, induced 52% of the inhibited buds to open. Radioassays of apple stems collected 11 and 9 days after injection, respectively, with 14C-ABA or 14C-BA indicated highly significant increases in radioactivity in the phloem, buds and new shoots compared to radioassays taken immediately after injection.

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Abstract

Postharvest dip of methyl 1 -(bu tyl carbamoyl)2-benzimidazolecarbamate (benomyl) prolonged the storage life of broccoli (Brassica oleracea L. Italica group), similar to the effect of 6-benzylamino purine (BA). Both compounds were effective in maintaining the green color of broccoli heads stored under high temperature conditions.

Open Access

The increase in the capitula of zinnia plants (Zinnia violacea Cav.) was investigated by analyzing the production of shoots. The effects of removing the buds for capitula and application of BA on the production of shoots were also evaluated. It took ≈40 to 50 days from the emergence of axillary buds to the opening of the capitula at the apices of the shoots from these axillary buds. The application of BA shortened the number of days for the same process. The difference in the number of days from emergence of the axillary buds to that of the first descendant axillary buds was ≈25. The total number of capitula opened was greater in plants with the bud removal treatment than in intact plants. Chemical name used: (N-phenylmethyl)-1H-purine-6-amine (BA).

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Generally, NAA is effective in inducing fruit thinning in `Delicious'. Although significant thinning may be induced, fruit size at harvest may not be closely related to crop load. Further, the magnitude of response to NAA may vary markedly between seasons. Herein, we present an analysis of response of `Redchief Delicious' over several years (tree age 11–14 years old) to high-volume sprays of NAA (15 mg·L–1), BA (25-50 mg·L–1), and CPPU (5 mg·L–1) at KFD of 8–12 mm. A single tree was used for each treatment replicated four to six times and response was measured by yield and fruit size distribution for each tree. In eight experiments over 4 years, NAA resulted in an average 22% reduction in yield, a 5.1% reduction in large fruit (70 mm+) and 2% reduction in small (<64 mm) fruit compared to NTC. There was a marked variation in response among years. Over 4 years, BA averaged a 5% decrease in yield, a 15% increase in large fruit and a 21% decrease in small fruit. In contrast, when NAA was combined with BA at 25-50 mg·L–1, yield decreased an average of 30%, large fruit decreased by 68%, and small fruit increased 8-fold (2.54 vs 20.6 kg/tree). CPPU alone (2-year study) had no significant effect on yield, but increased large fruit by 60% and significantly reduced production of small fruit. When CPPU was combined with NAA, yield was reduced in both years and the amount of large fruit was increased in 1995, but decreased in 1996. NAA had a very inhibitory effect on fruit size in 1996. One explanation may be that the crop was produced by lateral fruit (king flowers were lost to frost), and NAA has a greater inhibitory effect on lateral than king fruit. Results will be discussed in relation to studies with `Jonathan' and `Empire'.

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Abstract

Bulbils were produced in the umbels of onion plants when the bulbs were treated at the time of planting with PBA carried in methyl cellosolve. Methyl cellosolve alone and a PBA-acetone formulation did not induce bulbil formation.

Open Access

Callus initiation and growth and plantlet regeneration were studied using eight cultivars of Raphanus sativus L., including six Japanese radishes, one Chinese and one small `Comet' radish. The basal medium was composed of Murashige and Skoog inorganic salts, 2.0 mg myo-inositol/liter, 0.5 mg each of nicotinic acid and pyridoxine·HCl/liter, and 0.1 mg thiamine·HCl/liter, 30 g sucrose and 2 g Gelrite/liter. High callus yields were obtained on basal medium containing (mg·liter-1) 0.1 2,4-D and 1.0 BA for two Japanese radishes and 0.1 NAA and 1.0 kinetin for `Comet' radish. Shoots were regenerated from callus by subculturing on basal medium containing 0.1 or 1.0 mg BA/liter and then transferring to basal medium. Rooting occurred on basal medium. Although callus was obtained in all eight cultivars, shoots and plantlets were regenerated only from `Moriguchi', `Nerima Shirinaga', and `Comet'. Chemical names used: 2-(l-naphthyl) acetic acid (NAA); N-(phenylmethyl)-lH-purine-6-amine (BA); 2,4-dichlorophenoxy acetic acid (2,4-D); 6-(furfurylamino)purine (kinetin).

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In an attempt to improve the micropropagation protocol for lingonberry (Vaccinium vitis-idaea L.) developed at the Centre, two lingonberry clones were compared for in vitro shoot proliferation on two different media supplemented with varying levels of thidiazuron (TDZ). TDZ supported proliferation at low concentrations (0.1 to 1 μm) but inhibited shoot elongation. However, usable shoots were obtained within 4 weeks by transferring shoot cluster to medium containing 1 μm zeatin. Genotypes differed significantly with respect to multiplication rate with `EL1' producing the most shoots per explant. In both genotypes, shoot proliferation was greatly influenced by explant orientation. Changing the orientation of explants from vertically upright to horizontal increased axillary shoot number, but decreased shoot height and leaf number per shoot. Proliferated shoots were rooted on a 2 peat: 1 perlite (v/v) medium, and the plantlets were acclimatized and eventually established in the greenhouse.

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