Daminozide Treatment Research Articles

Daminozide enhances the vigor and steviol glycoside yield of stevia (Stevia rebaudiana Bert.) propagated in temporary immersion bioreactors

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.

Growth and Flowering by Relighting and Daminozide Treatment in the Flower Bud Formation Stage of Chrysanthemum morifolium ‘Baekma’ Cut Flowers

Growth and Flowering by Relighting and Daminozide Treatment in the Flower Bud Formation Stage of Chrysanthemum morifolium ‘Baekma’ Cut Flowers

Daminozide reduces red color intensity in herbaceous peony (Paeonia lactiflora Pall.) flowers by inhibiting the expression of flavonoid biosynthetic genes.

Daminozide is a plant growth retardant that inhibits 2-oxoglutarate-dependent dioxygenase activity in the gibberellin biosynthesis pathway, but few studies have focused on its effect on the flavonoid biosynthesis pathway involved in flower color. In the present study, the effect of daminozide on the regulation of flower color was investigated. An herbaceous peony (Paeonia lactiflora Pall.) cultivar 'Fenzhu Pan' was used as the material and treated with daminozide. Color parameters of petals were measured; flavonoid composition and content as well as flavonoid biosynthetic gene expression were monitored. The results showed that daminozide treatment caused less red coloration in herbaceous peony. The content of total anthocyanins was decreased by 23%, and the content of total anthoxanthins was increased by 8%; thus, it appeared that less red coloration in daminozide-treated flowers was associated with restricted anthocyanin accumulation. Furthermore, the gene expression patterns of flavonoid 3'-hydroxylase, dihydroflavonol 4-reductase and anthocyanidin synthase were lower after daminozide treatment, which could decrease anthocyanin accumulation and lead to less red coloration in flowers. These findings would improve our understanding of daminozide regulation of flower color in herbaceous peony.

EFFECT OF SOME GROWTH RETARDANTS ON GROWTH AND FLOWERING OF HELIANTHUS ANNUUS L. CV. SUNRICH ORANGE SUMMER 981V PLANTS A- EFFECT OF FOLIAR SPRAY TREATMENTS WITH ANCYMIDOL, DAMINOZIDE AND ETHEPHON

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.

English

A greenhouse pot experiment was carried out during November 2013 to May 2014. Winter wheat grains (Triticum aestivum L.), cultivars Abu-Ghureb and Cham6 were used to investigate the effect of soaking seeds in 300ppm of benzyl adenine (BA) or daminozide solutions for 6 hours before sowing vegetative, yield components, leaf chlorophylls and some chemical constituents of seeds. BA treatment led to significant increases in tiller number plant-1, chlorophyll b, P, dry gluten, N and protein contents of seeds. It also led to significant decreases in number of leaves plant-1. In addition, the number of tillers plant-1, shoots dry weight plant-1, P, N and protein contents of seeds were increased by daminozide treatment, but this caused a significant decrease in the plant height, number of leaves plant-1 and flag leaf area. Number of grains plant-1, weight of 1000 grains and grains yield were significantly increased by both treatments. Cultivar variability was noted for some tested parameters. The tall, N, P content and protein content of Abu-Ghureb cultivar were higher significantly than Sham6. The case was opposite with number of leaves plant-1, flag leaf area, shoots dry weight plant-1, spike length and grain number plant-1.

Improvement of compactness and floral quality in azalea by means of application of plant growth regulators

The ornamental industry's difficulties in producing compact and well branched plants have been the subject of extensive evaluation, the problems being compounded by the fact that each species, and even each cultivar, requires a specific protocol. In this work, growth regulators (daminozide, paclobutrazol and chlormequat chloride) and chemical pinching agents (fatty acids) were applied to reduce shoot extension with a view to lowering production costs whilst optimizing plant quality in the production of azalea japonica. Assessment of the effectiveness of the different treatments was achieved using image analysis as a quantitative method which we consider to be a faster and more objective technique than classic biometry. The results indicate that daminozide and paclobutrazol treatment are the best options to control vegetative development and to promote the flowering of azalea japonica in a cold and humid zone such as Asturias. However, daminozide treatment induces floral deformation in one of the tested cultivars, Blaauw's Pink.

Daminozide applied to the foliage of three potato cultivars increased tuber eye number

The plant growth regulator, daminozide, was applied to the foliage of Ranger Russet, Shepody and Nooksack potato (Solarium tuberosum L.) plants at 0, 0.62, 1.25, 2.5 and 5 g product·liter−1 to determine its effectiveness in increasing eye number and reducing average tuber weight. Total tuber yields were not affected. Daminozide treatment increased tuber eye number of each cultivar and did not alter the distribution of eyes between the stem and bud ends. After 5 g daminozide·liter−1 treatment, average eye number of the stem end and bud ends of Nooksack increased up to 1.0 eye, by 27% for Shepody and by 31% for Ranger Russet. The largest increases in eye number occurred in Ranger Russet. However, increasing daminozide concentration caused increased tuber elongation in Ranger Russet. Average tuber weight decreased significantly in response to daminozide treatment only in Shepody. As a seed tuber production aid, daminozide can be used to increase eye number, and in some cultivars, to reduce average tuber weight.

Influence of CuSO4 spectral filters, daminozide, and exogenous gibberellic acid on growth ofDendranthema Xgrandiflorum (Ramat.) Kitamura ‘bright golden anne’

The response of chrysanthemum plants to gibberellic acid (GA3) and daminozide, grown under 6% CuSO4 and water (control) spectral filters, was evaluated to determine the involvement of gibberellins in regulation of plant height under CuSO4 filters. The CuSO4 filter increased the red (R)/farred (FR), and blue (B)/R ratio (R=600–700 nm; FR =700–800 nm; B=400–500 nm) of transmitted light. PPF under 6% CuSO4 filter was reduced by about 34% compared to PPF under water filter which averaged about 750 μM·m−2·s−1. Control plants were shaded with Saran Wrap to ensure equal PPF as in the CuSO4 chamber. GA3 application increased plant height under both the control and CuSO4 filter, but the height increase under the CuSO4 filter was about 20% greater than that under the control filter. Daminozide treatment reduced plant height under the control and CuSO4 filter, but the height reduction in control plants was slightly greater than under the CuSO4 filter. The height reduction caused by daminozide was prevented by GA3 application in plants grown under the control or CuSO4 filter. The results suggest that GA3 may be partially involved in height reduction under CuSO4 filters.

Summer Pruning Affects Yield and Improves Fruit Quality of `McIntosh' Apples

The effects of summer pruning on the yield and quality of apples (Malus domestica Borkh.) from mature `Rogers McIntosh'/M.7 trees were assessed in 1986-88. Summer pruning from 1 July through 1 Sept. enhanced red coloring and increased the percentage of the crop graded U.S. Extra Fancy. Fruit weight was not altered by summer pruning. Total yield was reduced by summer pruning only in 1 year, however, in no year was the harvested yield reduced. The portion of the crop that was picked in the first harvest was increased by summer pruning. Dormant-pruning time was decreased by summer pruning, and the total time required for pruning was increased only 1 of the 2 years where it was measured. Summer pruning and daminozide treatment significantly increased the estimated net returns.

Effect of daminozide on survival, growth and yield of micropropagated potatoes

The effect of daminozide [Butanedioic acid mono (2,2-dimethyl hydrazide)] on growth, field establishment and productivity of micropropagated Kennebec and Russet Burbank potato was studied. Addition of daminozide to the medium significantly reduced stem length ofin vitro propagated plantlets. Optimal dose was 0.6 mg active ingredient per plant. This dose did not significantly alter the number of nodes and leaf area. Three transplanting methods were examined: direct from tissue culture to the field without protection; the same but with a plastic covering for protection; and after 7 days acclimation in a greenhouse but without protection in the field. Stand establishment ranged from 83.3 to 100%. The second transplanting method had the highest percentage establishment for both cultivars. The application of daminozide improved survival for all transplants of Kennebec and the directly planted plantlets of Russet Burbank. Independent of the daminozide treatment, plants of both cultivars hardened in the greenhouse prior to transplanting produced the highest number and yield of tubers. For Russet Burbank, daminozide caused a delay in tuberization but did not affect tuber bulking and haulm growth.

Responses of Daminozide-treated ‘Delicious’ and ‘Idared’ Apples to Simulated Low-ethylene CA Storage

Abstract Daminozide-treated and non treated ‘Delicious’ and ‘Idared’ apples (Malus domestica Borkh.) were stored for 7 to 7.5 months in simulated low-ethylene (<1 μl·liter−1) or normal-ethylene (500 μl·liter1) controlled-atmosphere (CA) storage. The simulated CA storage was a flow-through CA storage in 19-liter jars at 0°C. The storage atmosphere contained 2.5-3% O2, 3% CO2, 94-94.5% N2, and nearly 100% RH. Nontreated ‘Delicious’ and ‘Idared’ apples did not respond to low-ethylene CA, except that low-ethylene CA reduced the incidence of storage scaled on ‘Delicious’ apples. Daminozide-treated ‘Delicious’ apples did not respond to low-ethylene CA; the apples being firm after both low-ethylene and normal-ethylene CA storage. The response to low-ethylene CA by daminozide-treated ‘Idared’ apples was a reduced rate of softening of the apples after storage. The daminozide treatment significantly suppressed the ethylene production of both cultivars of apples in simulated low-ethylene CA storage. Chemical names used: butanedioic acid mono(2,2-dimethylhydrazide)(daminozide).

Opposing effects of daminozide and ethylene on the induction of flesh softening in apple fruits

SummaryApple trees were sprayed in late July with daminozide in four seasons to suppress ethylene production and softening of harvested fruit stored in 2% O2, <1% CO2 at 3.5°C. In two out of three years daminozide applied at 0.43 g l−1 was ineffective whereas ethylene production, softening and the rise of soluble pectin were inhibited by 0.85 or 1.7 g l−1. In the third season all the spray treatments were ineffective. In bulk storage experiments a combination of daminozide treatment and ethylene removal by potassium permanganate-impregnated vermiculite led to the retention of fruit firmness in two years out of three; untreated fruit and fruit which received only one of the treatments softened to a similar extent. The dual treatment also inhibited the solubilization of pectin and the synthesis of butyl and hexyl acetates during ripening after storage. Whereas daminozide-treated fruit had higher chlorophyll levels than untreated fruit, ethylene removal had no effect on chlorophyll loss. A taste panel distinguished the low ethylene-daminozide treated fruit as firmer and less mealy than other treatments. However, this fruit had a higher incidence of storage disorders.

Daminozide Protects Potato Seedlings from Metribuzin Phytotoxicity

Abstract The effect of daminozide as a plant growth retardant to protect potato seedlings from metribuzin injury was investigated. Plants of 6 potato cultivars were sprayed 42 days after planting with daminozide at 0, 2500, 5000 ppm concentrations. Four days after daminozide treatment, metribuzin at 0.56 kg/ha was applied. Within 3 days after metribuzin treatment, differences between potato cultivars in metribuzin tolerance was observed. Seven days after metribuzin application 25.2% to 42% of the control plants had more than 20% necrosis, and of this percentage, 0% to 13.9% plants were dead. Only 2.3% to 10.7% of the plants exhibited more than 20% metribuzin injury when pretreated with 2500 ppm daminozide. Potato plants treated with 5000 ppm daminozide were not damaged. The soluble solids of stem sap increased with daminozide rate. Protection from metribuzin injury in potato was associated with the increase in soluble solids in daminozide treated plants. Chemical name used: butanedioic acid mono (2, 2-dimethylhydrazide) (daminozide).

The effects of daminozide and under-soil heating on the growth of radish under winter conditions

The growth of radish cultivars ‘Saxa’, ‘Saxerre’, ‘Serra’, ‘Istar’, ‘Cherrybelle’ and ‘Robino’ was compared at 7 and 12°C under winter glasshouse conditions. ‘Serra’ alone produced marketable storage roots by 63 days at 7°C, but root weight was no greater at 12 than at 7°C; only ‘Robino’ produced significantly larger roots at the higher temperature. Under-soil heating applied to ‘Cherrybelle’ and ‘Robino’ grown at an air temperature of 7°C increased root growth, particularly in ‘Cherrybelle’. Daminozide treatment at 7°C increased total and storage root weight and root:shoot ratio of both cultivars. At 12°C, the only significant effect of daminozide treatment was reduced shoot weight in ‘Robino’.

The effects of daminozide on the levels of Indol-3yl-acetic acid and gibberellins in radish (Raphanus sativus L.) in relation to the control of storage root growth

The levels of indol-3yl-acetic acid and gibberellins were determined in shoots and storage roots of radish (Raphanus sativus L.) at various times during the vegetative growth cycle of control plants and plants in which the root to shoot ratio was modified by daminozide treatment. In control plants the onset of storage organ growth was preceded by a change in the hormone root to shoot ratio to favour the root. There was a general reduction in hormone levels in daminozide-treated plants but the pattern of their distribution in roots and shoots was very similar to that in control plants. Thus the effects of daminozide on increased storage root growth cannot be explained in terms of altered root to shoot hormone ratios.

Effect of Daminozide and Ethephon on Transplant Quality, Plant Growth and Development, and Yield of Processing Tomatoes1

Abstract Treatment of tomato transplants (Lycopersicon esculentum Mill.) with (2-chloroethyl)phosphonic acid (ethephon) at 100 to 500 ppm when flower buds were visible but not open resulted in flower abscission of the first fruiting cluster, adventitious root formation on the plant stem, increased dry-matter content and more rapid plant recovery following transplanting than untreated and/or clipped plants. Fruit maturity was earlier and more uniform on treated than untreated plants. Treatment of transplants with ethephon at 0.28 kg per ha, combined with a fruit-ripening ethephon treatment at 0.9 kg per ha, increased ripe-fruit yield from a once-over harvest compared with untreated or either treatment alone. Flower abscission on transplants was erratic from treatment with 2,500 or 5,000 ppm of butanedioic acid mono-(2,2-dimethylhydrazide) (daminozide), dry matter was increased, no adventitious roots developed, and transplant recovery was similar to that observed with untreated and/or clipped plants. Daminozide treatment had no influence on fruit maturity and yield.

Effects of calcium and daminozide on ethylene production and softening of apple fruits

Ethylene production of McIntosh apples was reduced by both a postharvest treatment with CaCl2 and a daminozide treatment applied in the field. The CaCl2 treatment was more effective than daminozide in reducing the rate of softening during storage at 1°C.

Effect of Daminozide on Yield and Quality of ‘Concord’ Grapes (Vitis labrusca L.) in Arkansas1

Abstract Succinic acid -2,2-dimethylhydrazide (daminozide, SADH) applied at first-bloom or peak-bloom at 1000, 2000, or 3000 ppm did not statistically alter yield in 1969. 1000 ppm applied between first- and peak-bloom in 1970 increased yield over the control, but no yield advantage was obtained at 500, 750, or 1000 ppm in 1971. Yield increases were due mainly to increases in the number of berries/cluster when daminozide was applied during early bloom as compared to application during verasion. Berry weight was reduced when the number of berries/cluster increased. Juice quality and vegetative growth of the grapevine generally decreased as yields increased due to daminozide application. Delaying harvest of grapevines partially overcame the retardation in maturity resulting from daminozide treatment.