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- Author or Editor: Sauveur Mahotiere x
During the Fall of 1993, four commercial growth retardants (B-nine, Cycocel, A-rest and Bonzi) were compared for their effectiveness in controlling the growth and development of three ornamental cabbage cultivars (white, red and pink) and two flowering ornamental kale cultivars (frizzy red and red peacock). Two weeks after transplanting; seedling of each cultivar were sprayed with aqueous solutions of the four commercial growth retardants. Treatments for each cultivar were arranged in a randomized complete block design with 6 replications. Plant height, plant width and dry weight were the parameters used to measure growth and development. Results showed that all the growth retardants except for cycocel significantly affected growth and development without any effect on head formation and color development. Bonzi caused the greatest growth suppression.
Effects of BA, Promalin and Dikegulac-sodium on frond number and overall growth in Boston Fern (Nephrolepis exaltata L.) were studies. Four weeks after transplanting, fern liners were sprayed with aqueous solutions of BA, Promalin and dikegulac-sodium. Chemical concentrations of BA and promalin ranged from 0 to 150 mg. liter-1 at 50 mg. liter-1 increments. Chemical concentrations of dikegulac-sodium ranged for 0 to 750 mg.liter-1 at 250 mg.liter-1 increments. Chemical treatments were arranged in a randomized complete block design with 6 replications. BA and Promalin significantly increased the number of fronds, average frond length, leaf area and dry weight as the concentration of the chemicals increased. In contrast, dikegulac-sodium significantly suppressed the average frond length, leaf area and dry weight when compared to the control. Similarly to BA and Promalin, dikegulac-sodium increased the number of fronds as the concentration of the chemical increased.
One-year-old greenhouse-grown `Mary Washington', `Emerald', `UC 157 F,', and `UC 157 F,' asparagus (Asparagus officinalis L.) seedlings were sprayed on 23 Sept. 1988 with dikegulac concentrations ranging from O to 750 mg·liter-1 in 150-mg·liter-1 increments. No significant shoot emergence occurred before frost killed the ferns in December. With increasing temperature in Jan. and Feb. 1989, dikegulac promoted shoot emergence in all cultivars, except `Mary Washington'. At 600 mg·liter-1 dikegulac had increased shoot emergence in `Emerald', `UC 157 F,', and `UC 157 F2' by 310%, 161%, and 305%, respectively, over the control on 2 Feb. After frosts killed the first shoots, all cultivars responded to treatment as temperature increased. Dikegulac did not affect the height and dry weight of `Mary Washington' ferns, but it reduced the height of `Emerald' without affecting its dry weight. Both height and dry weight of `UC 1571 F' and `UC 157 F2' were reduced by the chemical. There was a significant effect of cultivar on shoot production regardless of treatment, but no significant cultivar × dikegulac interaction on shoot emergence. However, there were significant effects of cultivar and cultivar × dikegulac interaction on height and dry weight of the ferns. After the ferns had been cut off on 9 Aug. 1989, only `UC 157 F1' and `UC 157 F2' showed increased shoot emergence. A second treatment of the plants with the chemical on 23 Sept. 1989 resulted in no significant increase in shoot emergence before or after freezing temperatures killed the ferns. Chemical name used: 2,3:4,6-bis-0-(l-methyl ethylidene)-a-L-xylo-2 -hexulofuranosonic acid (dikegulac).
Mary Washington, UC157F1, and UC157F2 asparagus cultivars were grown from 1-year-old crown under greenhouse conditions in 30-liter pots containing Pro-Mix medium. The roots were cut to 10 cm prior to planting on 12 Feb. 1991. On July 12, 1991 the plants were transferred outdoors and sprayed with BA, GA4/7 and Promalin at 400 mg. liter-1 using tap water as control. On July 16, 1991 the treated ferns were cut at ground level and the plants were returned to the greenhouse, and arranged in a RCB design. Seven reps with one pot/rep were used. Data on time of emergence of first shoots were recorded daily until all pots had produced at least 1 shoot. When all plants had sprouted, cumulative number of all shoots/pots was recorded weekly thereafter over 5 weeks. BA and Promalin reduced time of emergence of shoots and increased the number of shoots/plant. GA4/7 had no effect on shoot emergence or shoot number.
On Sept. 23, 1988, 12-month-old greenhouse-grown `Mary Washington', `Emerald', `UC 157 F1' and `UC 157 F2' asparagus seedlings were sprayed with dikegulac solutions ranging from 0 to 750 mg·l-1 with 150 mg·l-1 increments. The potted plants were then transferred to a lathhouse to simulate the weather conditions in the field. No significant shoot emergence occurred prior to killing frosts and low temperatures in December. The rise of the temperature in Jan. and Feb. 1989, promoted shoot emergence in all cultivars; but `Mary Washington' did not respond to the treatments. At 600 mg·l-1, the chemical increased shoot emergence in `Emerald', `UC 157 F1' and `UC 157 F2' by a respective cumulative average of 310, 161 and 305% over the control on 2 Feb. After intervening killing frosts and low temp, at the resumption of growth in late February 1989, `UC 157 F,' and `Mary Washington' were first to respond to the residual effects of the chemical, giving at 750 mg·l-1 a respective cumulative increase of 65 and 77% over the control. Dikegulac did not affect the height and dry weight of `Mary Washington' ferns. But it reduced the height of `Emerald' without affecting its dry weight.
Abstract
Dipping asparagus crowns (Asparagus officinalis L.) in 300 ppm dikegulac (Atrinal) solution significantly reduced the time of emergence and the height of asparagus shoots without affecting their fresh and dry weights. The number of shoots at complete emergence was not affected by the dikegulac treatment, but thereafter a significant increase occurred. Of the concentrations tested (0, 200, 300, and 400 ppm), 300 ppm was the most effective. After the top was cut off, the dikegulac treatment did not affect the time of emergence of the second shoots, but it did continue to increase their number. Chemical name used: 2,3:4,6-bis-O-(1-methylethylidene)-α-L-xylo-2-hexulofuranosonic acid (dikegulac).
Abstract
Spraying 9-month-old asparagus seedlings (Asparagus officinalis L.) with dikegulac-sodium (atrinal) solutions ranging from 0 to 500 ppm in 100-ppm increments increased the number of new shoots, particularly within the range of 300 to 500 ppm. The response was elicited 4 weeks after the treatment and continued thereafter over the 10 weeks, during which measurements were taken. Dikegulac did not affect the height or the fresh and dry weights of the plants for this first phase. Emergence of new shoots after the plants had been cut off was equally affected by dikegulac; 300 to 500 ppm was still the most effective. However, effectiveness was significant after 2 weeks. The height of plants was significantly reduced by the chemical, but the fresh and dry weights were not affected. At the third phase, none of the growth characteristics, including shoot emergence, was affected by the chemical. This lack of response may be attributable to the depletion of carbohydrate reserves in the fleshy roots. Chemical name used: 2,3:4,6-bis-O-(1-methylethylidene)-α-L-xylo-2-hexulofuranosonic acid (dikegulac).
Abstract
Excised onion (Allium cepa L.) shoot apices exposed directly to temperatures of 10 to 15°C grew more than those excised from similarly treated half or whole bulbs. The temperature pretreatments which promoted the greatest growth of excised onion shoots at 20° ranged from 5 to 12.5°. Exposure to 30° following a 10° treatment negated the promotive effect of the lower temperature.
Abstract
Both 6-furfurylaminopurine (kinetin) and sucrose substituted for exposure to 10°C in promoting growth of excised shoots of onion (Allium Cepa L.), but no additive effect of these substances and exposure to 10°C was observed. Ammonium (5-hydroxycarvacryl) trimethyl chloride piperidine carboxylate (ACPC) nullified the promotive effect of 10°C treatment when applied prior to temperature treatment but was without effect when applied after temperature treatment. Sucrose and kinetin partially overcame the effect of ACPC. Abscisic acid (ABA) inhibited growth of onion shoots and nullified growth promoted by exposure to 10°C regardless of time of application of ABA. Kinetin reduced the effect of ABA but sucrose did not.