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In Eastern Europe, the traditional marketing of cyclamen is in the period from the middle of February to the middle of March. The poor light of winter months and the higher number of plants (because of the reduction in heating costs) often result in elongated plants. To avoid this, it is recommended to use plant growth retardants. At the same time, another problem is that flowers do not rise from the level of rosette due to the unfavorable cultivation conditions. This can be solved with growth stimulants. In the experiment, we tested the effect of growth regulators on the growth of a frequently used variety of cyclamen. We used daminozide and paclobutrazol plant growth retardants for height control and gibberellic acid (GA) and benzyladenine (BAP) as growth promoters for increasing the number of flowers and the length of stems. The results show that daminozide and paclobutrazol are both effective for height control in cyclamen production. [ABSTRACT FROM AUTHOR]

Alar or Daminozide is a frequently used chemical in fruit orchard for preventing premature falling of fruits. The chemical enters the biological system following consumption of contaminated fruits. Previous study has characterized the neurotoxic effects of Daminozide in eukaryotic model Drosophila melanogaster. However, the underlying mechanisms by which Daminozide induces neurotoxicity is unclear. In the present study, we evaluated the toxic effects of Daminozide on a set of marker enzymes by exposing the flies of 2nd, 5th and 50th generations to 200 and 400 mg/L concentrations of the chemicals, respectively. The daminozide induced oxidative stress was determined by decreased level of total thiol content and reduced activities of the antioxidant enzymes like catalase, superoxide dismutase and detoxicant enzyme glutathione-s-transferase. Besides, a reduction of acetylcholinesterase activity was detected in the Daminozide treated group. This provides possible explanation to the previously determined neurotoxic effects of the chemicals. These results suggest that the daminozide disrupts the cellular antioxidant system which, in turn, increases the vulnerability for free radical induced molecular damage in eukaryotic model. [ABSTRACT FROM AUTHOR]

Daminozide, a plant growth regulator, is an effective inhibitor of the Jumonji domain-containing protein (JMJD) histone demethylase. Herein, four ruthenium(II)/rhenium(I)-daminozide conjugates, with molecular formulas [Ru(N-N)2bpy(4-CH2OH-4′-CH2O-daminozide)](PF6)2 (Ru-1/Ru-2) (N-N = 1,10-phenanthroline (phen, in Ru-1) and 4,7-diphenyl-1,10-phenanthroline (DIP, in Ru-2)) and Re(N-N)(CO)3(PyCH2O-daminozide) (Re-1/Re-2) (Py = pyridine, N-N = phen (in Re-1) and DIP (in Re-2)), were synthesized and characterized. Among these complexes, Ru-2 and Re-2 exhibited higher cytotoxicity against tumor cells than cisplatin. Upregulation of H3K9Me3 expression level was found in human cervical cancer cells (HeLa) treated with Ru-2 and Re-2, indicating that these two complexes can inhibit the activity of JMJD histone demethylase. Further investigation revealed that Re-2 can selectively accumulate in the mitochondria of HeLa cells. Both Ru-2 and Re-2 can cause mitochondrial damage, induce apoptosis, and inhibit cell migration and colony formation of HeLa cells. Overall, these complexes exhibit multiple anticancer functions, including inhibiting JMJD, inducing apoptosis, and inhibiting cell invasion, making them promising candidates for anticancer drugs. [ABSTRACT FROM AUTHOR]

In Eastern Europe, the traditional marketing of cyclamen is in the period from the middle of February to the middle of March. The poor light of winter months and the higher number of plants (because of the reduction in heating costs) often result in elongated plants. To avoid this, it is recommended to use plant growth retardants. At the same time, another problem is that flowers do not rise from the level of rosette due to the unfavorable cultivation conditions. This can be solved with growth stimulants. In the experiment, we tested the effect of growth regulators on the growth of a frequently used variety of cyclamen. We used daminozide and paclobutrazol plant growth retardants for height control and gibberellic acid (GA) and benzyladenine (BAP) as growth promoters for increasing the number of flowers and the length of stems. The results show that daminozide and paclobutrazol are both effective for height control in cyclamen production.

Early cone formation is a consistent issue in Fraser fir Christmas tree plantations in the eastern United States. Growers must remove cones by hand, resulting in significant labor costs, as cones degrade the aesthetic value of Christmas trees. In this study, we conducted two series of experiments in collaboration with several Christmas tree farms to determine the effectiveness of applying plant growth regulators (PGRs), specifically GA-inhibitors, in reducing cone formation and shoot growth in Fraser fir. In the first experiments we investigated the effectiveness of paclobutrazol, applied as a soil injection or as a foliar spray in reducing cone formation. The highest rate of soil application (300 mL of paclobutrazol per tree) reduced cumulative coning by approximately 38%. Leader growth control of soil applied paclobutrazol increased with application rate. In the second set of experiments, we compared four GA-inhibitors (paclobutrazol, chlormequat chloride, uniconazole-p, daminozide) applied as foliar sprays on coning and leader growth. Overall, paclobutrazol was the most effective compound for reducing coning and shoot growth. The results confirm earlier findings that application of GA-inhibitors can reduce, but not eliminate, coning. Likewise, PGR application can reduce shoot growth and possibly increase tree density but will not eliminate the need for shearing. [ABSTRACT FROM AUTHOR]

Daminozide (alar), a plant growth retardant, is used in different fruit orchard to make fruits attractive and reduce pre-harvest losses. Previously data demonstrated that acute daminozide exposure affected reproductive fitness and produced neurodegeneration in Drosophila melanogaster. The goal of this study was to determine whether continuous exposure to daminozide affects neuromuscular co-ordination in D. melanogaster as manifested in various behavioral responses. Fruit flies were exposed to 200 or 400 mg/L concentration of daminozide for two successive generations. Treated D. melanogaster were examined for the behaviors indicative of neuromuscular coordination and cognitive abilities, that include climbing, social interaction, adult grooming, migration, flight, male aggression, and adult courtship. Aberrant behavioral responses were noted among treated D. melanogaster of both sexes as evidenced by the following parameters: reduction in flight duration, abnormal social interaction, altered copulatory acts, and over-aggressiveness. Data suggest that daminozide produces impairment in neuromuscular coordination and cognitive ability in Drosophila, which was reflected as altered behavioral patterns. As Drosophila is considered as a reliable in vivo model utilized in toxicity testing, our findings may help us to anticipate and monitor potential daminozide-induced toxicity in animals and humans. [ABSTRACT FROM AUTHOR]

Chrysanthemum or chrysanths is an ornamental plant with high market potential. The application frequency of gibberellins synthesis inhibitor (daminozide) as a growth regulator on growth and quality of flowering in three types of chrysanthemums was observed in this study. The research was conducted from June to October 2019 in Pasuruan, East Java, Indonesia. A split-plot design was chosen, with chrysanthemum pot as the main plot based on growth phase and daminozide frequency as subplots. PGR was sprayed on the leaves at a dose of 15 ml per plant or 4000 ppm with 0, 2, and 3 applications. The frequency of daminozide application was effective to control the plant height and vase life. The application of daminozide increases the palisade thickness and reduces the internodes number, giving the plant a muscular appearance. Three times (2, 4, 6 weeks after sowing), and twice (2 and 4 weeks after planting) daminozide application for Tobaga (fast-growing) and Time Jewel (moderate-growing) chrysanthemum, respectively are needed to increase quality based on the market standard. Application of daminozide is not required for Cosmo Magenta (slow-growing) to reach the standard height (ca. 18-24 cm).

Stevia (Stevia rebaudiana Bertoni) produces steviol glycosides (SG), a group of diterpenoid secondary metabolites widely used as natural sweeteners. SGs share the same precursor with gibberellins (GAs), ent-kaurenoic acid. In this study, we attempted to increase the SG content in stevia propagated in Temporary Immersion Bioreactors (TIBs) by blocking ent-kaurenoic acid entry to the GA synthesis pathway using Daminozide (0, 10, 20 ppm), a known GA inhibitor. The maximum increase in biomass weight and SG content (up to 40% for stevioside and rebaudioside A) was observed following 10 ppm Daminozide treatment. The treatment also increased transcript accumulation for genes involved in SG biosynthesis, such as SrKA13H, SrUGT85C2, and SrUGT76G1, indicating that the SG pathway became more active due to GA pathway inhibition. Furthermore, GA inhibition following inhibitor exposure was also indicated by the upregulated expression of a GA biosynthesis gene (GA3ox) due to feedback regulation, and the downregulated expression of a GA catabolism gene (GA2ox2) as a result of feed-forward regulation. Key message: This study reports the impact of late-stage GA biosynthesis inhibition by chemical treatment to the modulation of SG yield from stevia in vitro culture; SG and GA pathways are related. [ABSTRACT FROM AUTHOR]

Daminozide, a plant growth regulator, is an effective inhibitor of the Jumonji domain-containing protein (JMJD) histone demethylase. Herein, four ruthenium(II)/rhenium(I)-daminozide conjugates, with molecular formulas [Ru(N-N)2bpy(4-CH2OH-4′-CH2O-daminozide)](PF6)2 (Ru-1/Ru-2) (N-N = 1,10-phenanthroline (phen, in Ru-1) and 4,7-diphenyl-1,10-phenanthroline (DIP, in Ru-2)) and Re(N-N)(CO)3(PyCH2O-daminozide) (Re-1/Re-2) (Py = pyridine, N-N = phen (in Re-1) and DIP (in Re-2)), were synthesized and characterized. Among these complexes, Ru-2 and Re-2 exhibited higher cytotoxicity against tumor cells than cisplatin. Upregulation of H3K9Me3 expression level was found in human cervical cancer cells (HeLa) treated with Ru-2 and Re-2, indicating that these two complexes can inhibit the activity of JMJD histone demethylase. Further investigation revealed that Re-2 can selectively accumulate in the mitochondria of HeLa cells. Both Ru-2 and Re-2 can cause mitochondrial damage, induce apoptosis, and inhibit cell migration and colony formation of HeLa cells. Overall, these complexes exhibit multiple anticancer functions, including inhibiting JMJD, inducing apoptosis, and inhibiting cell invasion, making them promising candidates for anticancer drugs.

Background: We explored neurotoxic and genotoxic effects of Daminozide, a fruit ripening retardant, on the brain of Drosophila melanogaster, based on our previous finding of DNA fragmentation in larval brain cell in the flies experimentally exposed to this chemicals., Methods: Adult flies were subjected to two distinct concentrations of daminozide (200 mg/L and 400 mg/L) mixed in culture medium, followed by an examination of specific behaviors such as courtship conditioning and aversive phototaxis, which serve as indicators of cognitive functions. We investigated brain histology and histochemistry to assess the overall toxicity of daminozide, focusing on neuron type-specific effects. Additionally, we conducted studies on gene expression specific to neuronal function. Statistical comparisons were then made between the exposed and control flies across all tested attributes., Results: The outcome of behavioral assays suggested deleterious effects of Daminozide on learning, short term and long term memory function. Histological examination of brain sections revealed cellular degeneration, within Kenyon cell neuropiles in Daminozide-exposed flies. Neurone specific Immuno-histochemistry study revealed significant reduction of dopaminergic and glutaminergic neurones with discernible reduction in cellular counts, alteration in cell and nuclear morphology among daminozide exposed flies. Gene expression analyses demonstrated upregulation of rutabaga (rut), hb9 and down regulation of PKa- C1, CrebB, Ace and nAchRbeta-1 in exposed flies which suggest dysregulation of gene functions involved in motor neuron activity, learning, and memory., Conclusion: Taken together, our findings suggests that Daminozide induces multifaceted harmful impacts on the neural terrain of Drosophila melanogaster, posing a threat to its cognitive abilities., Competing Interests: Declaration of Competing Interest Authors declare no conflict of interest. The study is academic in nature., (Copyright © 2024. Published by Elsevier B.V.)

The present study was conducted at the Postharvest Lab. of Ornamental Plants and Landscape Gardening Res. Dept., Hort. Res. Inst., Giza, Egypt in March of 2016 and 2017 seasons, to examine the effect of some pulsing solutions on improving the quality of limonium cut flowers.Limoniumcut flowerswere pulsedin silver thiosulfate (STS) at 500 mg/l for 1/4 and 1/2 h, silver nitrate (AgNO3) at 500 mg/l for 1/4 and 1/2 h, AgNO3 at one g/l for 1/4 and 1/2 h, sodium benzoate at 250 mg/l for 12 and 24 h, sodium benzoate at 500 mg/l for 12 and 24 h, daminozide at 25 mg/l for 12 and 24 h and daminozide at 50 mg/l for 12 and 24 h followed by transferring to a holding solution 8-hydroxyqunoline sulphate (HQS) at 200 mg/l + sucrose (20 g/l). Distilled water was used as a control treatment. The obtained results indicated that treatment of Limonium sinuatum cv. Girlie Wings cut flowers treated by STS at 500 mg/l for 1/2 h enhanced water uptake, relative fresh weight, dry weight percentage of cut flowers, floret opening percentage, pigments content, total carbohydrate percentage and total phenols as well as inhibiting growth of all isolated microorganisms and improved quality of flowers, followed by cut flowers treated with STS at 500 mg/l for 1/4 h then AgNO3 500 mg/l for 1/2 h.

Stevia (Stevia rebaudiana Bertoni) is a source of steviol glycoside, a natural sweetener which has almost zero calorie and glycemic index. Steviol glycoside shares the same precursor with gibberellin (GA), ent-kaurenoic acid. Therefore, to manipulate the biosynthesis pathway of steviol glycoside, a gradient of late-stage GA biosynthesis inhibitors, Daminozide and Prohexadione-Ca, was applied to the thin-layer liquid culture of stevia, which was 10 mL of liquid medium in the 100-mL Erlenmeyer flask. The culture was incubated for 3 weeks, followed by the observation of growth parameters and steviol glycoside content. Results showed that both Daminozide and Prohexadione-Ca significantly increased the steviol glycoside content, indicating that the disruption of GA biosynthesis could divert the metabolic pathway toward steviol glycoside production. However, the inhibition effect of Prohexadione-Ca was stronger than Daminozide, and caused poor growth of stevia plantlets. Therefore, Daminozide at the concentrations of 10 ppm and 20 ppm was potential to modulate steviol glycoside production from the stevia culture. [ABSTRACT FROM AUTHOR]

• Solubility of daminozide in twelve solvents was determined. • Solubility of daminozide was correlated by five models. • Hansen solubility parameters was used to evaluate the solubility behavior. • Apparent thermodynamic properties of daminozide in the selected solvents was estimated. In the present study, solubility of daminozide was determined in twelve neat solvents (N,N-Dimethylformamide (DMF), 2-methoxyethanol, N-Methyl-2-pyrrolidone (NMP), 2-ethoxyethanol, Acetonitrile (MeCN), 2-propoxyethanol, methanol, ethanol, n -propanol, i -propanol, n -pentanol, 2-butoxyethanol) by using the gravimetrical method under the pressure of 0.1 MPa and temperature from 283.15 to 323.15 K. The maximum solubility value (102 x 1) of daminozide was found in NMP at 323.15 K (10.04), while the minimum solubility value (102 x 1) of daminozide was found in n -pentanol at 283.15 K (0.0149). At the temperature of 298.15 K, the order of the experimental solubility values (100 x 1) of daminozide in twelve neat solvents was: NMP (5.523) > DMF (3.294) > methanol (1.395) > 2-methoxyethanol (0.7839) > ethanol (0.5515) > 2-ethoxyethanol (0.3816) > n -propanol (0.2175) > i -propanol (0.1099) > 2-propoxyethanol (0.1083) > 2-butoxyethanol (0.0632) > MeCN (0.0386) > n -pentanol (0.0344). Five models including van't Hoff model, Buchowski-Ksiazczak λh model, NRTL model, UNIQUAC model and Jouyban model were employed to correlate and analyze the experimental solubility of daminozide. Based on the principle of similar compatibility, the miscibility of daminozide in the selected solvents was discussed with the help of Hansen solubility parameters (HSPs). Finally, the apparent thermodynamic properties were investigated and results indicated that the dissolution mechanism of daminozide in all selected solvents was an entropy-driven and endothermic process. [ABSTRACT FROM AUTHOR]

This study included one factor with four growth retardant application methods of daminozide at 500 mg.l-1 concentration (without addition, sapling base soaking, drench, and spraying methods) on oleander sapling four months age. The experiment was conducted in a lath-house, Department of Horticulture and Landscaping, College of Agriculture, Tikrit University, during the growing season of 2016. The experiment was designed in a complete randomized design with three replications. The results showed that daminozide applications caused a significant effect in growth characteristics. Drench application gave less plant height 62.87 cm. Spray application resulted in the highest chlorophyll content (10.61 mg.g-1 fresh weight). Highest content of oleandrin was 0.25 mg.g-1 and 47.82 mg.kg-1 of rutin to sapling base soaking treatment.

Beyond the inhibitory action against the gibberellin biosynthesis, some plant growth retardants (PGRs) can play an important role in regulating plant responses to abiotic stress through the induction of different tolerance mechanisms. The aim of the present study was the exploitation of the potential of PGRs in enhancing the resistance to drought stress in Stevia rebaudiana Bert. Therefore, the effects of three PGRs on stevia plants grown under drought stress condition were investigated. Stevia plants were first subjected to water stress and, second, treated with PGRs to detect PGRs effect on biometric, productive and phytochemical characteristics of drought stressed-plants. The control plants were uniformly irrigated at 3-day intervals, while water-stress conditions were imposed by watering the plants at 12-day intervals. Subsequently, the Chlorocholine chloride (CCC, as Copalyl diphosphate synthase inhibitor and Kaurene synthase inhibitor), Paclobutrazol (PBZ, as Kaurene oxidase inhibitor) and Daminozide (DAM, as anti-gibberellins) were applied in drought stressed-plants. The CCC and DAM were sprayed on stevia shoots, while PBZ was drenched. The obtained results showed that leaf dry weight of stevia plants was significantly reduced by drought stress, but this parameter increased as a consequence of CCC and PBZ treatments. Drought stress also caused a significant reduction in total steviol glycoside (SVglys) content. This reduction was more pronounced in drought stressed-plants treated with CCC, while PBZ was able to counteract the SVglys reduction, with SVgly content similar to that observed in the control. Similarly, PBZ was able to increase the soluble sugar production and total antioxidant capacity in the leaves of stressed-stevia plants. These findings suggested that CCC and, in particular, PBZ had a protective effect on stevia growth under drought stress by induction of antioxidant defenses and soluble sugar production. CCC seems to inhibit gibberellin biosynthesis, preventing the SVglys production, while DAM and PBZ, as gibberellin inhibitors, didn't have a negative effect on SVglys production in drought stressed-plants. This observation seems to emphasize their role in limiting the rate of target enzymes of CCC in SVglys biosynthetic pathway. Moreover, the induction of glucose production, as a substrate for SVglys biosynthesis, could be a convincing evidence for SVglys promotion in PBZ treated-plants. • Plant growth regulators could alleviate drought stress in stevia. • PBZ was was effective in alleviating drought in stevia, stimulating growth and SVglys biosynthesis. • PBZ positive effects might be due to increased antioxidant activity and glucose production • Chlorocholine chloride target enzymes could act as rate limiting factor in the steviol glycosides biosynthesis. • Osmotic adjustment occurred through over production of sucrose and fructose molecules and antioxidant activity induction. [ABSTRACT FROM AUTHOR]

Hygrohypnum subeugyrium was first reported for Britain in 1976, but it has been ignored in subsequent British floras and identification guides. Morphologically it is a distinct species. New localities were discovered during a meeting of the British Bryological Society in Scotland in 2017. A subsequent revision of herbarium material has shown that H. subeugyrium is widely distributed in Scotland and occurs southwards to a few localities in England and Wales. Its extra-European distribution is extended to include the Himalayan region (Sikkim and Yunnan). It is described and illustrated, and its diagnostic characters are discussed. [ABSTRACT FROM AUTHOR]

Pot experiments were carried out at the nursery of Hort. Res. Inst, Giza, Egypt throughout the two successive seasons of 2014 and 2015. The work embodied in this paper was to study the influence of some growth regulators (daminozide, ancymidol and ethephon) on sunflower (Helianthus annuus L. cv. Sunrich Orange Summer 981V) plant for achieving the hope of producing dwarf plant of good quality, suitable for using as a pot plant. Results indicated that most treatments reduced stem length of the treated plants with the superiority of 2450 ppm daminozide treatment which induced 50% reduction in such trait, compared to the control plants in the two seasons. However, stem diameter and number of internodes/stem were improved in response to all the used treatments. Internode length, stem fresh and dry weights were decreased with few exceptions, but the greatest decrease in these criteria was attained by daminozide treatment at any rate and ethephon one at 250 ppm. Number of leaves/plant were increased by the various treatments. Root length increased over control with few exceptions in both seasons. However, the highest averages in most measurements were achieved by ancymidol, especially at 20 ppm level. A significant flowering earliness in the two seasons was noticed in plants sprayed with ethephon at 250 ppm. The least number of days from flower bud appearance to opening was obtained by the 20 ppm ancymidol treatment, but the plants treated with the other treatments took longer time to anthesis. Ethephon treatments elevated the mean number of lateral buds/stem to the maximum, while ancymidol ones gave the largest flower heads. Number of ray flowers/head, disc diameter and flower head fresh and dry weights were improved due to most treatments. Content of photosynthetic pigments were slightly improved with few exceptions. Total phenols content reached the maximum by ancymidol treatments, followed by the ethephon ones. However, total indoles content was not affected by most of the used treatments. In addition, the percent of total soluble sugars was increased by ancymidol at 5 ppm, daminozide at 2450 ppm and ethephon at 500 ppm treatments, while other treatments declined it. On the other hand, the percent of N, P and K was generally decreased in response to the various treatments, with few exceptions as compared to control.

Pot experiments were carried out at the nursery of Hort. Res. Inst, Giza, Egypt throughout the two successive seasons of 2014 and 2015. The work embodied in this paper was to study the influence of some growth regulators (daminozide, ancymidol and ethephon) on sunflower (Helianthus annuus L. cv. Sunrich Orange Summer 981V) plant for achieving the hope of producing dwarf plant of good quality. The objective of this investigation was to detect the response of sunflower plants to tank mix ratios and application methods of ancymidol, daminozide and ethephon for production of a dwarfed and picturesque specimen in an appropriate size. The results indicated that all the used combinations significantly decreased stem length of the treated plants. The shortest stems and internodes were obtained by ancymidol at either 5 or 20 ppm (seed soaking) + 500 ppm ethephon (spray). Stem diameter was increased by all combinations to reach the maximum by 5 ppm ancymidol (spray) + 500 ppm ethephon (spray). The number of internode/stem was not greatly affected by the used combinations. However, the number of leaves/plant was significantly increased by all treatments. Also, all combinations caused a marked increment in the root length, with the superiority of 20 ppm ancymidol (seed soaking) + 2450 ppm daminozide (spray), which scored the longest roots in the two seasons. Spraying plants with 5 ppm ancymidol + 250 ppm ethephon or 20 ppm ancymidol + 500 ppm ethephons induced the greatest precocity in flower bud appearance and opening. Seed soaking in 20 ppm ancymidol solution and spraying with 1250 ppm daminozide reduced number of days from flower bud appearance to its opening . The mean number of lateral buds/stem, number of ray flowers/head and disc diameter were significantly improved, with few exceptions due to the different combinations than control plants in both seasons. Data, revealed that the highest content of chlorophyll a, b, carotenoids and total phenols were scored by spraying with either 5 or 20 ppm ancymidol + 500 ppm ethephon solutions. Total indoles and total soluble sugars were inconsistent and the percent of N was generally decreased. As for P%, it increased by most combinations, but K% increased only by combining between ancymidol + ethephon.

A simple high-throughput liquid chromatography/tandem mass spectrometry (LC-MS/MS) multiresidue analysis method was developed for the simultaneous determination of polar pesticides, plant growth regulators and other polar compounds. These included amitrole, chlormequat, mepiquat, cyromazine, ETU, PTU, perchlorate, and daminozide using a mixed-mode column. A 10 g test portion was shaken with acidified methanol for 10 min. After centrifugation, the sample extract was injected and analyzed within 11 min by LC-MS-MS. This column eliminated the need for derivatization or the use of ion paring reagent. Two MS-MS transitions were monitored in the method for each target compound to achieve true positive identification. Eight isotopically-labeled internal standards corresponding to each analyte were used to correct for matrix suppression effect and/or instrument signal drift. The average recovery for all analytes at 20, 40, and 250 ng/g (n = 6) ranged from 73-136%, with a relative standard deviation of ≤ 20%. [ABSTRACT FROM AUTHOR]

Steviol glycosides (SGs) are natural compounds present in Stevia rebaudiana (Bertoni) Bertoni, which are approximately 200-400 times sweeter than sucrose. A biosynthetic pathway of SGs shares a biosynthetic pathway of gibberellin (GA) through a formation of ent-kaurenoic acid. Previous studies have demonstrated that SG-related genes are upregulated by exogenous GA treatment. However, the transcription level of UGT85C2, which is involved in a glycosylation step to steviol from steviolmonoside and suggests a rate-limiting step in the SGs biosynthesis, remains controversial in GA treatments. To have a detailed understanding of the relationship between SGs and GAs, a concentration gradient of exogenous GA3, GA inhibitor daminozide (DAM), and naphthaleneacetic acid (NAA) was used for treatment by the leaf infiltration method. Results showed that transcription level of UGT85C2 and the total number of stevioside and rebaudioside-A induced by GA3, DAM, or NAA treatment were significantly upregulated compared to an untreated group. These results suggest that the GA biosynthetic pathway affects the number of SGs and that hormonal crosstalk occurs between GA and auxin, which changes the number of SGs in S. rebaudiana. Controlling the GA biosynthesis could be considered to modulate the yield of SGs. [ABSTRACT FROM AUTHOR]

An experiment was conducted to study the effect of graded concentrations of foliar applied growth retardants (cycocel and B-nine) on the growth and flowering of Chrysanthemum morifolium cv. Flirt. Uniform rooted cuttings raised in pot soil culture received spray applications of growth retardants viz., cycocel and B-nine prepared in 0.1% Tween 80. Cycocel was applied at 1000, 2500 and 5000 mgL-1, whereas B-nine was applied at 100, 250 and 500 mgL-1 concentrations. Plants were sprayed at 2 and 6 weeks after transplantation. Visual observations, plant height, fresh mass, dry mass, number of laterals, number of inflorescences and inflorescence diameter were recorded at periodic intervals. Cycocel treated plants recorded a significant increase in fresh and dry mass of whole plants, leaves and roots, whereas B-nine treated plants were comparable with the controls. Cycocel and B-nine treated plants showed early emergence of buds and inflorescences, whereas no significant effect was recorded on number of laterals. Cycocel application resulted in the increase in inflorescence number. The present results suggest that the treatment effect may be cultivar dependant as many other cultivars of chrysanthemums have been chemically tailored with desired effects using cycocel and B-nine. [ABSTRACT FROM AUTHOR]

Ruellia brittoniana is a fast growth plant with a strong tendency of vegetative growth that occurs at the expense of flowering capability, thus regular pruning for height control is necessary. Chemical pruning using suitable growth retardant may offer similar effects on stem and branch elongation, and flowering of the plants could be promoted. This study was carried out to evaluate the varying rate of daminozide and frequencies of application on the growth and flowering of Ruellia brittoniana. Results of a two factorial experiment involving two application frequencies (double and triple application) and five concentrations of daminozide (0, 500, 1000, 1500, 2000 mg L-1) showed that different concentration of daminozide and application frequencies significantly affected the vegetative growth, photosynthesis, transpiration and chlorophyll content. Daminozide at 500 mg L-1 with triple application caused a reduction of 42% in plant height compared to control with less detrimental effects on flower number. Daminozide application had not affected on the stomatal conductance. Application of daminozide at 500 mg L-1 given in triple application was found to be effective in producing short, compact plants with more flowers. [ABSTRACT FROM AUTHOR]

El principal objetivo de este estudio fue encontrar la mejor práctica para inducir la brotación en tubérculos de papa en dormancia. Comparamos dos protocolos para romper la dormancia, basados en inmersión de yemas (ojos) aislados del tubérculo, en una solución acuosa de ácido giberélico (GA3) y cinetina (estándar 1), o en una solución acuosa de GA3, tiourea, y daminozida (estándar 2), con un nuevo enfoque reportado basado en etanol. Probamos el efecto del etanol solo o en combinación con GA3 y/o cinetina en la liberación de la dormancia y en la brotación de los tubérculos de papa. Como modelo usamos dos genotipos de papa (variedades Pasat y Dorota), con dormancia larga de 5 y 10 semanas, respectivamente. Mostramos que el estándar 2 fue el tratamiento más efectivo tanto para romper la dormancia como para promover el crecimiento del brote, especialmente para la variedad Dorota, para la cual el tratamiento indujo un 82.3% de los ojos del tubérculo a brotar 28 días después del tratamiento, y a producir 93.2% de plantas emergidas después de 28 días subsecuentes de cultivo en invernadero. Para esta variedad se observó eficacia similar con la combinación de 4% de etanol con GA3 y cinetina. La misma concentración de etanol en combinación con GA3, pero sin cinetina, fue el tratamiento más eficiente para romper la dormancia de la variedad Pasat. No obstante, la diferencia entre las diversas combinaciones de tratamientos fue insignificante estadísticamente. El etanol solo o en combinación con cinetina indujo pobremente el rompimiento de la dormancia, confirmando el principal papel de GA3 en el rompimiento artificial de la dormancia. De aquí que nuestro estudio mostró que el estándar 2 es el enfoque más efectivo para el rompimiento de la dormancia por lo menos con variedades de dormancia larga. [ABSTRACT FROM AUTHOR]

Eucomis autumnalis (Mill.) Chitt., commonly known as pineapple lily, is a new ornamental pot plant with great marketing potential. This work evaluated the effects of two gibberellin synthesis inhibitors (daminozide and flurprimidol) applied as commercial plant growth regulators (PGRs) B-Nine and Topflor on the growth, flowering, and bulb yield in E. autumnalis. The PGRs were applied three times as substrate drenches or foliar sprays at the concentration of 15 mg dm-3 (flurprimidol) or 4250 mg dm-3 (daminozide). Plant growth was restricted only by flurprimidol, particularly when it was applied as substrate drenches. Plant height was reduced by 48% at anthesis and by 38% at flower senescence, compared to the untreated control. Regardless of the application method, flurprimidol increased the leaf greenness index (SPAD) and bulb weight. Daminozide treatments were ineffective in controlling plant height and negatively influenced bulb weight. Foliar sprays of daminozide increased the length of inflorescences and the number of flowers per inflorescence. [ABSTRACT FROM AUTHOR]

A glasshouse experiment was carried out to study the effect of Plant Growth Regulators (PGRs) on the production of pre-basic seed (PBS) potatoes, cv. Janakdev at Khumaltar, (1360 masl) Lalitpur, Nepal during autumn and spring seasons of 2014 and 2015 respectively. Four - week old virus free in vitro plantlets grown in tissue culture laboratory were planted with 20 cm distance between rows and 10 cm between plantlets under glasshouse in completely randomized design. Three growth regulators, paclobutrazol (50 ppm), daminozide (100 ppm), chlormequat chloride (Cycocel) (200 ppm) and simple water as control were used for single foliar spray 6 weeks after transplanting with four replications. Analysis showed that there were significant differences on growth parameters; plant survival, plant uniformity, plant height and yield components; number of minitubers per plant and per square meter in both the seasons. Significantly maximum number of potato minitubers was recorded in growth retardants treated plants as compared to control. Experimental results showed that maximum number of minituber (22.9/plant and 668.2/m2) in autumn and (23.7/plant and 1185.0/m2) in spring season were gained from paclobutrazole spray, which were statistically differed from those of other growth regulators and control. Plants without PGR and treated with daminozide produced the least amount of minituber per unit area. Plant height decreased in all growth regulators over control due to their inhibiting effect on growth of the plants. paclobutrazol significantly reduced plant height but produced larger and heavier minitubers compared to other treatments. Hence, the best PGR for optimum enhancement of minituber number and size was paclobutrazol. The results suggested that paclobutrazol could be used in pre-basic seed potato production, leading to maximum minituber production which ultimately gave higher returns. The study concluded that spraying growth retarding chemicals at grand growth stage checked the excessive vegetative growth and increased the number and size of minituber. [ABSTRACT FROM AUTHOR]

The experiment was conducted to inhibit the growth of dwarf alstroemeria cultivars 'Rosalina' and 'Dorotea' using flurprimidol and daminozide. Additionally, the effect of these retardants on days to anthesis, flowering shoots number, diameter and longevity of florets was evaluated. In vitro propagated plants, grown in 12 cm pots were treated with single sprays of flurprimidol (7,5, 15, 22,5 mg l-1) and daminozide (2500, 3500, 4500 mg 1-1) following second pruning, when shoots were 9-12 cm long. Well retarded plants of both dwarf alstroemeria cultivars were obtained when plants were sprayed with flurprimidol at 22.5 mg 1-1. Plants treated with daminozide at all tested concentrations were to tall to be grown in 12 cm pots. Flurprimidol significantly reduced the canopy diameter, number of flowering shoots of alstroemeria cultivars 'Rosalina' and 'Dorotea' and floret size of cultivar 'Rosalina'. Daminozide had no effect on the number of days to flower but flurprimidol delayed flowering of tested cultivars only at concentration of22.5 mg 1-1. Intensified green leaf colour was observed on flurprimidol treated plants. The chemical names used: a-(1-methylethyl)-a-[4-(trifluoromethyloxy)-phenyl]-5-pyrimidine-methanol (flurprimidol), butanedioic acid mono (2,2-dimethylhydrazide) (daminozide).

The objective of the presented experiment was the showing of the possibility of replacing daminozide, contained in the preparation B-Nine 85 SP, by metconazole, contained in Caramba 60 SL preparation, in pot cultivation of pot chrysanthemum ‘Leticia Time Yellow’. Experiment was carried out in three cycles: in the spring, beginning 10 April; in the summer, beginning 11 June; and in the autumn, beginning 13 August, 2007. The metconazole contained in the Caramba 60 SL preparation was able to impede the growth of ‘Leticia Time Yellow’ chrysanthemum as effectively as the daminozide contained in the B-Nine 85 SP preparation. However, the effectiveness of metconazole depended on its concentration and on the dose of the preparation, on the number of treatments and on the growing term in the plastic tunnel. In the summer term of cultivation, the effect of metconazole applied only once in a concentration of 300 mg dm-3 was comparable with the effectiveness of daminozide applied twice in a concentration of 2,550 mg dm-3, and in the autumn cultivation, the effectiveness was even higher. In addition, no retardation of flowering was recorded, either in relation to the plants sprayed with daminozide or in relation to the control plants not sprayed with any retardant.

Foliar sprays of (PGR's) Cycocel and Alar were applied at concentrations of 250, 500, and 750 ppm after 105 days after plantation (square and boll setting stage) to Egyptian cotton cultivar planted at three plant densities (166.000, 222.000, and 333.000 plant ha-1). Number of opened bolls plant-1, seed-cotton yield plant-1, and earliness increased as plant density decreased in both years, as did seed-cotton and lint yield ha-1 in the second season. In the first year, the intermediate plant density gave highest yields. Plant density had no significant effect on lint percentage or fiber properties. Both Cycocel and Alar increased the number of opened bolls plant-1, boll weight, seed and lint indices, seed-cotton yield plant-1 and both seed-cotton and lint yield ha-1, but effects were not always significant and response varied for different traits. Neither Cycocel nor Alar affected lint percentage, yield earliness or fiber properties at any plant density. [ABSTRACT FROM AUTHOR]

Compounds with N , N -dimethylhydrazine moieties ((CH 3 ) 2 N-N-) form N -nitrosodimethylamine (NDMA) during ozonation, but the relevant reaction chemistry is hitherto poorly understood. This study investigated the reaction kinetics and mechanisms of NDMA formation during ozonation of unsymmetrical dimethylhydrazine (UDMH) and daminozide (DMZ) as structural model N , N -dimethylhydrazine compounds. The reaction of ozone with these NDMA precursor compounds was fast, and k O3 at pH 7 was 2 × 10 6 M −1 s −1 for UDMH and 5 × 10 5 M −1 s −1 for DMZ. Molar NDMA yields (i.e., Δ[NDMA]/Δ[precursor] × 100) were 84% and 100% for UDMH and DMZ, respectively, determined at molar ozone dose ratio ([O 3 ] 0 /[precursor] 0 ) of ≥4 in the presence of tert -butanol as hydroxyl radical ( OH) scavenger. The molar NDMA yields decreased significantly in the absence of tert -butanol, indicating OH formation and its subsequent reaction with the parent precursors forming negligible NDMA. The k OH at pH 7 was 4.9 × 10 9 M −1 s −1 and 3.4 × 10 9 M −1 s −1 for UDMH and DMZ, respectively. Reaction mechanisms are proposed in which an ozone adduct is formed at the nitrogen next to N , N -dimethylamine which decomposes via homolytic and heterolytic cleavages of the –N + -O-O-O − bond, forming NDMA as a final product. The heterolytic cleavage pathway explains the significant OH formation via radical intermediates. Overall, significant NDMA formation was found to be unavoidable during ozonation or even O 3 /H 2 O 2 treatment of waters containing N , N -dimethylhydrazine compounds due to their rapid reaction with ozone forming NDMA with high yield. Thus, source control or pre-treatment of N , N -dimethylhydrazine precursors and post-treatment of NDMA are proposed as the mitigation options. [ABSTRACT FROM AUTHOR]

Zinnias have good potential to be used as flowering, potted plants, being a quick source of novelty for the floriculture industry with the aid of growth retardants. This study evaluated the effect of growth retardants on development and production of short, compact and attractive plants of potted 'Lilliput' Zinnia elegans, a highly ornamental zinnia with low cost seeds. Trials were set up in randomized blocks, with ten treatments (control and three treatments of each retardant: daminozide, paclobutrazol and chlormequat) and four replications (two pots per experimental unit, with one plant per 0.6-L pot). Paclobutrazol (0.5, 0.75 and 1.0 mg a.i. per pot) and chlormequat (1.0, 2.0 and 3.0 g L-1) were applied as a single drench (40 mL per pot), and daminozide (2.5, 3.75 and 5.0 g L-1) as a single foliar spray to runoff (10 mL per pot), at apical flower bud stage. Daminozide (2.5 and 3.75 g L-1), paclobutrazol (0.5, 0.75 and 1.0 mg a.i. per pot) and chlormequat at 1.0 g L-1 significantly reduced plant height and side branches length, without affecting flower diameter, delaying production cycle and causing phytotoxicity symptoms. However, plants were not short and compact enough to meet market quality demand. Chlormequat (2.0 and 3.0 g L-1) caused phytotoxicity symptoms and daminozide (5.0 g L-1) delayed production cycle.As zínias têm grande potencial como plantas floríferas envasadas e representam rápida fonte de novidade para a floricultura com o auxílio de retardadores de crescimento. Avaliaram-se os efeitos de retardadores de crescimento no desenvolvimento e na produção de plantas envasadas de porte baixo, compactas e atrativas de 'Lilliput' Zinnia elegans, cultivar altamente ornamental, com sementes de baixo custo. O delineamento experimental foi em blocos casualizados, com dez tratamentos (controle e três concentrações de cada retardador: daminozide, paclobutrazol e chlormequat) e quatro repetições (dois vasos por unidade experimental, com uma planta por vaso de 0,6 L). Paclobutrazol (0,5; 0,75 e 1,0 mg i.a. por vaso) e chlormequat (1,0; 2,0 e 3,0 g L-1) foram aplicados ao substrato (40 mL por vaso), enquanto o daminozide (2,5; 3,75 e 5,0 g L-1) foi aplicado através de pulverização foliar (10 mL por vaso), no estádio de gema floral apical visível. Daminozide (2,5 e 3,75 g L-1), paclobutrazol (0,5; 0,75 e 1,0 mg i.a. por vaso) e 1,0 g L-1 de chlormequat reduziram significativamente a altura das plantas e o comprimento dos ramos laterais, sem afetar o diâmetro dos capítulos, atrasar o ciclo de produção e causar fitotoxicidade. Entretanto, as plantas não se apresentaram suficientemente baixas e compactas para atender às exigências de qualidade do mercado. Chlormequat (2,0 e 3,0 g L-1) causou fitotoxicidade e daminozide (5,0 g L-1) aumentou o ciclo de produção.