Uniconazole Concentration Research Articles

Uniconazole Suppresses Bypass Shoot Development and Alters Flowering of Two Forcing Azalea Cultivars

`Redwings' and `Gloria' azaleas (Rhododendron × `Redwings' and `Gloria') were treated with foliar sprays of uniconazole, paclobutrazol, or daminozide to suppress bypass shoot development and promote flower initiation and development. Uniconazole at 5 and 25 mg·liter-1 suppressed bypass shoot development of `Redwings' and `Gloria', respectively. Flowering of `Gloria', but not `Redwings', was delayed slightly with uniconazole sprays up to 25 mg·liter-1; with the highest uniconazole concentration, 200 mg·liter-1, flowering was delayed as much as 18 days. Flower count of `Gloria' was not affected by lower concentrations of uniconazole, but it was greatly reduced in both cultivars with concentrations above 75 mg·liter-1. Uniconazole was more active than paclobutrazol sprays of similar concentrations or than two daminozide sprays of 3000 mg·liter–1. Chemical names used: (E)-1-(p-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-1-penten-3-ol (uniconazole); (2RS,3RS)-1-(4-chlorophenyl)-2-(1,1-dimethylethyl)-(1H-1,2,4,-triazol-l-yl-)pentan-3-ol (paclobutrazol); butanedioic acid mono(2,2-dimethylhydrazide (daminozide),

EFFICACY AND POSTHARVEST LONGEVITY OF UNICONAZOLE TREATMENT ON POLKA-DOT PLANT

The objective of the research was to determine the effectiveness of uniconazole on Hypoestes phyllostachya Bak. cv. Pink Splash and to compare the effect and persistence of uniconazole with chlormequat and daminozide for limiting stem elongation during post-greenhouse, low light conditions. Uniconazole at 5.0 mg·liter-1 reduced all measured plant dimensions to the same degree as chlormequat at 2500 mg· liter-l when both chemicals were applied twice as foliar sprays at a two week interval. These treatments resulted in the most compact and aesthetically pleasing 0.4-liter potted plants. However, this uniconazole treatment was not as persistent in postproduction low light conditions as chlormequat. By the fifth week under low light conditions, only the highest drench concentration of uniconazole tested (0.10 mg a.i. per pot) remained the same height as chlormequat treated plants.

Interactive effects of GAs, CKs and growth retardants on the germination of celery seeds

The germination of whole seeds of celery (Apium graveolens L.) was inhibited by paclobutrazol, ancymidol and lower concentrations of uniconazole. The growth retardants daminozide, AMO 1618 and chlormequat chloride inhibited the germination of cut seeds only, indicating that the seed coat prevents the penetration of these compounds at the examined concentrations. Application of a mixture of the gibberellins A4 and A7 (GA 4/7) reversed the inhibition of all the examined growth retardants. Cytokinins (artificial or natural) had no effect when applied alone and did not interact with GA4/7 in the light. However, in the dark the cytokinins at some concentrations and GA4/7 had a synergistic effect in reversing the inhibition caused by growth retardants to whole seeds or in promoting the germination of whole seeds. It is therefore suggested that the major effect on seed of exogenous cytokinins when applied together with GA's is to increase the uptake of gibberellins by the seeds.

EFFECT OF PREPLANT BULB SOAK WITH UNICONAZOLE ON GROWTH AND DEVELOPMENT OF EASTER LILY

Plant growth and flower development of Easter lilies (Lilium longiflorum) were evaluated for 3 years (1988-90). Bulbs of cvs. Ace and Nellie White were soaked preplant in solutions of uniconazole at cones. of 0 to 5 ppm at durations of 1 to 5 minutes and compared to bulbs soaked in ancymidol at 5 to 40 ppm. Time of bulb soak had no effect on amount of solution absorbed and on growth and flower development. Plant height from bulbs soaked in water alone was variable among the 3 years, ranging from 56 to 70 cm for Nellie White and 55 to 89 cm for Ace. Ancymidol concs. of 5, 10, 20, and 40 ppm retarded plant height 10.8, 14.5, 33.8, and 46.2%, respectively. Uniconazole solutions at 0.625, 1.25, 2.5, 5, 10, and 20 ppm produced Nellie White plants 16.7, 70.4, 56.8, 46.9, 39.3, and 30.8% of the height of the water soaked bulbs, respectively. Response of Ace to similar uniconazole concentrations was slightly less. High uniconazole concentration (> 5 ppm) delayed flowering time and reduced the number of floral buds which developed. Variability among plants within uniconazole treatments was large and would not be acceptable commercially.

GROWTH AND FLOWERING OF MANDEVILLA `ALICE DU PONT' IN RESPONSE TO UNICONAZOLE.

Vegetative growth and flowering of Mandevilla `Alice du Pont' in response to foliar-applied uniconazole were determined in 3 experiments. Plants pruned to 2 nodes were treated with foliar applications of 30, 60, 90, and 120 ppm uniconazole. All uniconazole rates induced temporary leaf cupping and suppressed growth excessively for at least 6 weeks; thereafter, plants grew similarly to the control. Single applications of 5, 10, 15, and 20 ppm uniconazole were not effective in controlling vegetative growth, but multiple applications of 5.0, 7.5, 10.0, 12.5, 15.0, 17.5, and 20.0 ppm uniconazole provided acceptable, but not excessive, suppression of internode elongation. As the concentration of uniconazole increased, the interval between applications increased. Flowering was delayed and bloom size was reduced as uniconazole rate increased.

Uniconazole-induced changes in abscisic acid, total amino acids, and proline in Phaseolus vulgaris

Fourteen-day-old bean ( Phaseolus vulgaris) plants were soil treated with 100 ml of either 10 mg liter −1 uniconazole (( E)-( p-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-1-penten-3-ol) or 3 mg liter −1 abscisic acid (ABA). Over the next 10 days, the concentration of uniconazole, ABA, total amino acids, and proline in the primary leaves and their stomatal resistance were monitored. In plants treated with exogenous ABA, there was a single transient increase in stomatal resistance with the endogeous concentrations of ABA, proline, and total amino acids increasing to a maximum approximately 2 days after treatment. In the uniconazole-treated plants, the accumulation of uniconazole in the primary leaves was not linear but was biphasic over the duration of the experiments. This correlated very closely to changes in the stomatal resistance. The concentrations of ABA, proline, and total amino acids followed a similar pattern with the first and second peaks occurring 3–4 and 8–9 days after treatment, respectively. These results suggest that the accumulation of ABA may be the direct result of the presence of uniconazole in the primary leaf tissue. Furthermore, the accumulation of proline and other amino acids that have been associated with environmental stress resistance is likely mediated through the uniconazole-induced accumulation of ABA. A radioimmunoassay for the rapid and sensitive quantification of ABA is also outlined.

Emergence, Growth, and Freezing Tolerance of Tomato Seedlings Grown from Uniconazole-treated Seed

Seeds of Lycopersicon esculentum Mill. cv. UC 82L were treated with hypertonic priming solutions containing KNO3 and K3PO4(10 g·liter-1 each), and various concentrations of uniconazole before sowing. Treatment of the seed with priming solution only hastened emergence by ≈ 2 days compared to untreated seed sown directly from the packet, but did not affect total emergence after 12 days. Addition of uniconazole to the priming solution had no significant effect on speed of emergence or total emergence after 12 days compared to the primed control. Seed priming plus uniconazole at 1 or 10 mg·liter-1 reduced seedling height after 2 weeks by ≈ 20% compared to the primed control. Uniconazole had no effect on the mortality of either hardened or nonhardened seedlings exposed to below-freezing temperatures for 3 hr. These data suggest that treatment of tomato seed with hypertonic solutions containing uniconazole would be of little practical value in protecting seedlings from freeze damage. Chemical names used: (E)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-yl)penten-3-ol (uniconazole).

Whole-plant Response of Easter Lilies to Ancymidol and Uniconazole

Abstract All growth retardant treatments (ancymidol, 50 mg·liter−1, one or two sprays; uniconazole, 5, 10, or 15 mg·liter−1, one or two sprays; 20 mg·liter−1, one spray) reduced Easter lily (Lilium longiflorum Thunb.) plant heights when compared to controls. Plant heights decreased linearly with increasing concentration of uniconazole for both one- and two-spray treatments. High concentrations of uniconazole delayed anthesis; ancymidol treatments did not. Individual corolla length was not affected by treatments. Treatments did not affect daughter bulb depletion or new daughter bulb growth. Total leaf area and leaf dry weight decreased as uniconazole concentration increased; ancymidol treatments did not affect leaf area, but did reduce leaf dry weight. Leaf total soluble carbohydrate decreased with increasing concentration of uniconazole. Chemical names used: α-cyclopropyl-α-(4-methoxyphenyl)-5-pyrimidine-methanol (ancymidol); (E)-1-(p-chlorophenyI)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-1-penten-3-ol (uniconazole).

Imposition of water stress in wheat seedlings improves the efficacy of uniconazole‐induced thermal resistance

Winter wheat (Triticum aestivum L. cv. Fredrick) seedlings (seed) treated with different concentrations of uniconazole (S‐3307) were water stressed by withholding water for 2, 4 and 6 days. Subsequently, the water‐stressed seedlings were exposed to heat shock at 45°C for 3 h. Chlorophyll fluorescence, stress‐ethylene and percentage survival were the parameters used to monitor the efficacy of protection against thermal stress by uniconazole. In the control seedlings, water stress for 2 days prior to heat shock provided minimal protection, whereas uniconazole protected both water‐stressed and non‐stressed seedlings from heat injury. However, the degree of protection by uniconazole was enhanced if the seedlings were subjected to water stress (2–4 days) prior to the heat shock. In addition to protection against heat injury, uniconazole also reduced stress‐induced (water and heat) ethytene levels.

Influence of Growth Regulators on Root and Shoot Characters of Onion

Context: The growth behaviour and yield of any crop plants are governed by their genetic potential, climatic conditions and the supply of nutrients. Specific control of these processes can be done by the application of plant bioregulators of natural or synthetic origin.Objectives: The aim of the present investigation was to study the effect of different plant growth regulators on root and shoot emergence, and root and shoot length of onion.Materials and Methods: Onion. var "Taherpuri" was used as plant material and four growth regulators namely GA3, Uniconazol, CCC and 2,3,6-TBA along with water as control with different concentration viz. 100, 150, 200, 250 and 300 ppm were used as treatment. Onion bulbs were placed on vials containing different doses of growth regulators. Data recorded on root and shoot emergence and their lengths after different days of setting the experiment.Results: Higher concentrations of uniconazole necessitated maximum days for root and shoot emergence whereas GA3 required minimum days. Root length decreased gradually with increasing the concentrations of all the growth regulators at different days of emergence. Higher concentrations of GA3 produced longest shoot whereas same concentrations of uniconazole produced the shortest than the lower ones at different days of emergence. The highly significant and negative correlation was found between days to root emergence and shoot length and between days to shoot emergence and shoot length but highly significant and positive correlation was found between root length and shoot length. Conclusion: GA3 required minimum days to root and shoot emergence and promote the vegetative growth of onion whereas uniconazole and CCC are retards and 2,3,6-TBA shows a little retarding effect.Key words: Growth regulators; Root and shoot characters; OnionDOI: 10.3329/jbs.v17i0.7101J. bio-sci. 17: 51-55, 2009