Uniconazole Concentration Research Articles

Residues and Dietary Risk Assessment of Prohexadione-Ca and Uniconazole in Oryza sativa L. and Citrus reticulata Blanco by Liquid Chromatography-Tandem Mass Spectrometry.

A simple and sensitive method for the simultaneous quantitation of prohexadione-Ca and uniconazole in the field experiment of Oryza sativa L. and Citrus reticulata Blanco was established using solid-phase extraction (SPE) with polymer anion exchange (PAX) and Florisil followed by LC-MS/MS. The method demonstrated excellent linearity (R2 > 0.999 0), trueness (recoveries between 95~105%), precision (CVs between 0.8~12%), sensitivity, and repeatability (LOQ of 0.05 and 0.01 mg/kg, respectively). Residue tests were conducted in the field at 12 representative sites in China, revealing final concentrations of prohexadione-Ca and uniconazole in brown rice, rice hull, and rice straw to be below 0.05 mg/kg, while in whole citrus fruit and citrus pulp, they were below 0.01 mg/kg. These were below the maximum residue limits specified in China. The chronic dietary risks of prohexadione-Ca and uniconazole in rice crops and citrus fruits were calculated to be 0.48% and 0.91%, respectively. Our research suggests that the chronic risk associated with the daily consumption of rice crops and citrus fruit at the recommended dosage is acceptable.

Growth and Physiological Responses by Treatment Concentration and Method of Uniconazole in Veronica kiusiana var. glabrifolia

Growth and Physiological Responses by Treatment Concentration and Method of Uniconazole in Veronica kiusiana var. glabrifolia

Effects of uniconazole on the physiological characteristics and cadmium accumulation of Cyphomandra betacea seedlings

AbstractTo determine if the uniconazole concentration(s) whether could enhance the cadmium (Cd) tolerance of Cyphomandra betacea seedlings, the effects of spray treatments with various uniconazole concentrations (0, 5, 10, 20, and 50 mg/L) on the physiological characteristics and Cd accumulation of C. betacea seedlings were studied in a hydroponic experiment. The results indicated that uniconazole significantly decreased the Cd content of C. betacea seedling stems, leaves, and shoots, but significantly increased the biomass of all analyzed seedling parts. Additionally, the leaf chlorophyll a, chlorophyll b, and carotenoid contents as well as the net photosynthetic rate, transpiration rate, stomatal conductance, and CO2 concentration of intercellular were higher for the uniconazole‐treated C. betacea seedlings than for the control seedlings. The optimal uniconazole concentration significantly promoted the superoxide dismutase, peroxidase, and catalase activities and the soluble protein content of C. betacea leaves. Moreover, uniconazole decreased the soluble sugar content of the C. betacea roots and stems, but had the opposite effect on the soluble sugar content of the leaves and shoots. The 20 mg/L uniconazole treatment resulted in the highest C. betacea seedling biomass and the lowest Cd content, indicating this concentration may be useful for improving C. betacea seedling growth in Cd‐contaminated soils.

The Dwarfing Effects of Different Plant Growth Retardants on Magnolia wufengensis L.Y. Ma et L. R. Wang

The effects of varieties, concentrations, and number of applications of plant growth retardants (PGRs) on the morphological, physiological, and endogenous hormones of Magnolia wufengensis L.Y. Ma et L. R. Wang were assessed to obtain the most suitable dwarfing protocol for M. wufengensis and to provide theoretical support and technical guidance for the cultivation and promotion of this species. One-year-old M. wufengensis ‘Jiaohong No. 2’ grafted seedlings served as the experimental materials. In the first part of the experiment, three PGRs (uniconazole, paclobutrazol, prohexadione calcium), three concentrations (500, 1000, 1500 ppm), and three applications (one, three, and five applications) were applied in dwarfing experiments to perform L9 (34) orthogonal tests. In the second part of the study, dwarfing experiments were supplemented with different high uniconazole concentrations (0, 1500, 2000, 2500 ppm). Spraying 1500 ppm uniconazole five times achieved the best M. wufengensis dwarfing effect, related indicators of M. wufengensis under this treatment were better than other treatment combinations. Here, M. wufengensis plant height, internode length, scion diameter, and node number were significantly reduced by 56.9%, 62.6%, 72.8%, and 74.4%, respectively, compared with the control group. This treatment increased superoxide dismutase (SOD) activity by 66.0%, peroxidase (POD) activity by 85.0%, soluble protein contents by 43.3%, and soluble sugar contents by 27.6%, and reduced malondialdehyde (MDA) contents by 32.1% in leaves of M. wufengensis compared with the control. The stress resistance of M. wufengensis was enhanced. The treatment also reduced gibberellin (GA3) levels by 73.0%, auxin (IAA) by 58.0%, and zeatin (ZT) by 70.6%, and increased (abscisic acid) ABA by 98.1% in the leaves of M. wufengensis. The uniconazole supplementation experiment also showed that 1500 ppm was the optimal uniconazole concentration. The leaves exhibited abnormalities such as crinkling or adhesion when 2000 or 2500 ppm was applied. Given the importance of morphological indicators and dwarfing for the ornamental value of M. wufengensis, the optimal dwarfing treatment for M. wufengensis was spraying 1500 ppm uniconazole five times.

Foliar application of uniconazole improves yield through enhancement of photosynthate partitioning and translocation to tuberous roots in sweetpotato

ABSTRACTTo examine the effects of uniconazole (UCZ) on the distribution and transport of photosynthate in sweetpotatoes, three spraying levels of UCZ, 0 (control), 50 and 100 mg L−1, were exposed to an experimental field cultivated with Jishu26 (‘J26ʹ) and Xushu32 (‘X32ʹ) varieties. Compared to control, the distribution of carbon-13 (13C) was significantly higher in the tuberous roots of both varieties treated with UCZ. In addition, UCZ treatments promoted a desirable top-to-base sucrose gradient and significant greater declines in the top-to-bottom amino acid and potassium ion (K+) gradients along the stem. Higher tuberous root yields were found in the UCZ-treated ‘J26ʹ and ‘X32ʹ. In comparison to 50 mg L−1 UCZ, ‘J26ʹ treated with 100 mg L−1 UCZ exhibited significantly higher distribution ratio of 13C in tuberous root, and reductions in the top-to-bottom amino acid and K+ gradients along the stems at 105 and 150 days after planting. Furthermore, 100 mg L−1 of UCZ application exhibited a significantly higher tuberous root yield. For ‘X32ʹ, the two concentrations of UCZ demonstrated no significant differences in these parameters. A reasonable distribution structure of photosynthates that responsible for high yields is associated with the desirable sucrose, ammonia nitrogen (N) or K+ gradient along the stems caused by UCZ application.

Uniconazole increases starch content in duckweed (Lemna aequinoctialis Welw.)

Uniconazole has been used to improve starch production in plants through the regulation of endogenous hormone levels. Here, we reported the effect of this compound on the starch accumulation in a duckweed plant ( Lemna aequinoctialis ). L. aequinoctialis was grown in Hoagland medium supplemented with different uniconazole concentrations: 400, 800, and 1600 mg/L. The results showed that treatment with 800 mg/L uniconazole significantly increased plant growth rate, doubling time and its chlorophyll content. Consequently, the starch content also increased by 1.5 fold upon treatment with 800 mg/L uniconazole. We, therefore, concluded that uniconazole treatment offers an effective means to enhance the production of starch in L. aequinoctialis .

Uniconazole application strategies to improve lignin biosynthesis, lodging resistance and production of maize in semiarid regions

Lodging stress significantly reduces the grain yield and quality. Uniconazole is a plant growth regulator and it can potentially reduce lodging stress by enhancing lignin metabolism and lodging resistance. We conducted a field study in the semiarid regions of China to determine suitable uniconazole application strategies based on the culm morphological characteristics, rind penetration strength, lignin metabolism, lodging stress, and grain yield from summer maize during 2015 and 2016. Seeds were soaked in uniconazole at concentrations of 0 (SCK0), 25 (SU25), 50 (SU50) and 75 (SU75) mg kg−1. In another experiment, uniconazole was applied to the foliage at concentrations of 0 (FCK0), 25 (FU25), 50 (FU50) and 75 (FU75) mg L−1 at the eight-leaf stage. Our results suggested that uniconazole significantly alleviated lodging stress by enhancing lignin metabolism and optimizing the culm morphological characteristics. Uniconazole significantly increased the lignin content and activities of lignin-related enzymes such as phenylalanine ammonia-lyase, cinnamyl alcohol dehydrogenase, tyrosine ammonia-lyase, and peroxidase, where their maximum values were obtained with SU25 and FU25 treatments. The grain yield and ear characteristics increased but then decreased as the uniconazole concentration increased, where treatments SU25 and FU25 obtained the highest grain yield and ear characteristics. Seed soaking significantly enhanced lignin accumulation and alleviated lodging stress compared with foliar application. Our results suggest that the lignin content is closely related to lodging resistance in maize and higher lignin accumulation in the third basal internode can improve lodging resistance. Uniconazole application significantly reduced the risk of lodging stress and improved the grain yield of maize, where the most effective treatments were soaking seeds at 25 mg kg−1 and foliar application of 25 mg L−1 at the eight-leaf stage.

Effects of Seed Dressing with Uniconazole Powder on Lodging Resistance of Culm in Common Buckwheat

Lodging is one of the important factors affecting the yield and quality of common buckwheat(Fagopyrum esculentum M.) worldwide. Ningqiao 1, a cultivar of common buckwheat with moderate lodging resistance was used in this study to investigate the dynamic changes of lodging behavior, yield, culm snapping resistance, lodging index, culm morphological characteristics and culm anatomical structure seed dressing with uniconazole powder(0, 100, 200, and 300 mg kg–1). The results indicated that seed dressing with uniconazole powder had significantly effects on the lodging resistance of culm in common buckwheat. With the increase of uniconazole powder concentration, the yield, culm snapping resistance, diameter of the 2nd internode, dry weight of the 2nd internode, filling degree, mechanical tissue layer number, mechanical tissue thickness, culm wall thickness, vascular bundle number, and vascular bundle area showed an increased-decreased trend, whereas, the lodging percentage, lodging index, plant height, culm gravity height, culm fresh weight, and length of the 2nd internode showed an decreased-increased trend. In this case, the treatment of seed dressing with 200 mg kg–1 uniconazole powder could optimize the culm structure, improve the culm quality, reduce the lodging risk, and enhance the yield of common buckwheat.

Paclobutrazol or uniconazole effects on ethylene sensitivity of potted ornamental plants and plugs

Effects of paclobutrazol on postharvest ethylene sensitivity of potted cuphea (Cuphea hyssopifolia Kunth) and petunia (Petunia×hybrida Vilm.) plants, and uniconazole on portulaca (Portulaca oleracea L.) plugs were evaluated. Paclobutrazol was applied as a drench at 0, 1, 2, or 4mgL−1 per 12.5cm pot for cuphea, or 0, 2, 4, or 8mgL−1 per 15.2cm pot for petunia, while uniconazole was applied at 0, 2.0, 4.0, or 8.0mgL−1 with a volume of 0.21Lm−2 as a foliar spray for portulaca plugs. With an increase in paclobutrazol dose or uniconazole concentration, plant growth [plant height and diameter (potted plants only), shoot fresh weight, or dry weight] was controlled for all species tested. While use of paclobutrazol or uniconazole controlled excessive plant growth of all three species, the plant growth retardants had no effect on postharvest ethylene sensitivity as most flowers abscised from all plants exposed to exogenous ethylene. However, both paclobutrazol and uniconazole reduced postharvest flower abscission of plants not treated with exogenous ethylene. During simulated shipping and marketing, paclobutrazol and uniconazole maintained darker foliage and controlled height. Drench applications of 2–4mgL−1 paclobutrazol for cuphea and 4–8mgL−1 for petunia potted plants and spray applications of 4–8mgL−1 uniconazole for portulaca plugs produced compact, high quality plants while also extending postharvest longevity and quality.

Effects of uniconazole on the lignin metabolism and lodging resistance of culm in common buckwheat (Fagopyrum esculentum M.)

Lodging is one of the major factors contributing to common buckwheat (Fagopyrum esculentum M.) yield and quality reduction. This study was conducted to determine whether lignin metabolism and lodging resistance of culm in common buckwheat could be affected by uniconzole. Two common buckwheat cultivars, Youqiao2 (lodging-tolerant cultivar; YQ2) and Ukraine daliqiao (lodging-susceptible cultivar; UD), were used to investigate the effects of uniconzole on the common buckwheat lodging behavior, lignin metabolism in culm and its relation to lodging resistance. In one experiment, seed dressing with uniconazole at the rate of 0 (CK1), 100 (P1), 200 (P2), and 300 (P3)mgkg−1 were applied. In the second experiment, foliar spraying with uniconazole at the rate of 0 (CK2), 25 (S1), 50 (S2), 75 (S3), and 100 (S4)mgL−1 were applied at the four-leaf stage. Results showed that the lignin content was significantly and positively correlated with culm snapping resistance, while significantly and negatively correlated with lodging index and lodging percentage. The lodging index and lodging percentage decreased and then increased with the increase of the concentration of uniconazole, and their minimum values appeared in the P2 and S3 treatments. The yield, culm snapping resistance, lignin content, and the enzyme activities of phenylalanine ammonia-lyase (PAL), 4-coumarate:CoA ligase (4CL), cinnamyl alcohol dehydrogenase (CAD), and peroxidase (POD) increased and then decreased with the increase of the concentration of uniconazole, and their maximum values appeared in the P2 and S3 treatments. These results suggested that the lignin content is closely related to the lodging resistance of common buckwheat, and higher lignin content could strengthen the lodging resistance of common buckwheat. Uniconazole significantly decreased the risk of lodging occurred by increasing the lignin content and its related enzymes activities of culm, and the concentrations which showed the greatest effects were 200mgkg−1 with seed dressing and 75mgL−1 with foliar spraying.

Effects of plant growth regulator uniconazole on plant morphology and biomass allocation of Salvia miltiorrhiza

In this study, we use pot experiment to evaluate the effect of plant growth regulator on plant morphology and biomass allocation of Salvia miltiorrhiza. Different concentrations of uniconazole were supplied to S. miltioohiza by means of foliar spray. Height, breadth and stem diameter were measured dynamically, the biomass of leaf, stem, flower and fruit, root biomass and biomass ratio were also examined at the harvest time. Owing to the treatment, plant morphology showed significant changes, the height had been greatly reduced and the breadth decreased largely. Meanwhile, the biomass allocation changed too. The biomass ratio of leaf and stem had been notably reduced while the biomass ratio of root had been increased remarkably. It appears that foliar application of uniconazole during vigorous growth period in S. miltioohiza has dramatic effect on dwarfing plant and improving resistant to lodging. This measure could also be applied to condensed cultivation of S. miltioohiza to increase production.

Influence of Seed Treatment with Uniconazole Powder on Soybean Growth, Photosynthesis, Dry Matter Accumulation after Flowering and Yield in Relay Strip Intercropping System

The relay strip intercropping system of wheat-corn-soybean is widely used in southwest China. However, it is hard to produce soybean stably with this system, since the growth of soybean plants is slower under shading by corn at the seedling stage, and it is compensated by accelerated growth after the symbiotic stage. Soybean plants show excessive vegetative growth due to more rain during the flowering stage, which results in fallen petals, fallen pods and lower yield. This study investigated whether seed treatment with uniconazole powder (0, 2, 4 and 8 mg kg–1 seed) suppresses excessive vegetative growth of soybean plants during the flowering stage and delays senescence of photosynthetically active leaves at the pod-setting stage. If such events are correlated with changes in photosynthesis, they may affect dry matter accumulation and seed yield in the relay stripping system. Uniconazole promoted biomass accumulation from 31 (R3) to 61 (R5) days after flowering (DAF) and seed yield. Seed treatment with uniconazole raised the net photosynthetic rate, stomatal conductance, transpiration rate, and total chlorophyll and chlorophyll a contents. In contrast, uniconazole reduced leaf area index (LAI) from 1 DAF (R1) to 46 DAF (R4) with the increase in uniconazole concentration, whereas, uniconazole significantly increased LAI at 61 DAF, and the greatest promotion occurred at 2 mg kg–1 treatment. The study clearly showed that uniconazole effectively suppressed excessive vegetative growth of soybean during flowering stage, delayed senescence of photosynthetically active leaves at pod-setting stage and induced higher yield, which were related to the changes in photosynthetic rate, chlorophyll content, dry matter accumulation and LAI in the relay strip intercropping system.

Studies on the effects on growth and antioxidant responses of two marine microalgal species to uniconazole

Uniconazole, as a plant growth retardant, can enhance stress tolerance in plants, possibly because of improved antioxidation defense mechanisms with higher activities of superoxide dismutase (SOD) and peroxidase (POD) enzymes that retard lipid peroxidation and membrane deterioration. These years much attention has been focused on the responses of antioxidant system in plants to uniconazole stress, but such studies on aquatic organism are very few. Moreover, no information is available on growth and antioxidant response in marine microalgae to uniconazole. In this paper, the growth and antioxidant responses of two marine microalgal species, Platymonas helgolandica and Pavlova viridis, at six uniconazole concentrations (0–15 mg L−1) were investigated. The results demonstrated that 3 mg L−1 uniconazole could increase significantly chlorophyll a and carbohydrate contents of P. helgolandica (P < 0.05). Higher concentrations (≥12 mg L−1) of uniconazole could inhibit significantly the growth, dry weight, chlorophyll-a and carbohydrate contents of P. helgolandica and P. viridis (P < 0.05). Uniconazole caused a significant increase in lipid peroxidation production (MDA) at higher concentrations (≥ 9 mg L−1). The activities of antioxidant enzymes, superoxide dismutase (SOD) and catalase (CAT) were enhanced remarkably at low concentrations of uniconazole. However, significant reduction of SOD and CAT activities was observed at higher concentrations of uniconazole.

Effects of CuSO4 and Uniconazole on Mature Embryo Culture in Japonica Rice

In order to establish the system of high frequency plant regeneration for japonica rice mature embryos, the effects of different concentrations of CuSO4 and uniconazole on in vitro culture of mature embryos were studied using three rice cultivars of Kongyu 131, Longjing 24, and Dongnong 425 as test materials. The results showed that callus induction and differentiation of japonica rice mature embryos were apparently improved on the medium with 10–15 μmol • L−1 CuSO4 and 0.50–1.00 mg • L−1 uniconazole. Induction and differentiation rates of different genotype rice mature embryos displayed different sensitivities to CuSO4 and uniconazole. For the callus induction frequency of three varieties, the optimal concentration of CuSO4 was 15.0 mol • L−1. When the concentration of CuSO4 was 15 μmol • L−1, the plantlet differentiation rates of Kongyu 131 and Dongnong 425 got to the highest, while the concentration of CuSO4 was 10 μmol • L−1 for Longjing 24. For the callus induction and plantlet differentiation rates of Kongyu 131 and Dongnong 425, the ideal concentration of uniconazole was 0.50 mg • L−1 and for Longjing 24 was 1.00 mg • L−1.

EFFECT OF UNICONAZOLE ON FLOWERING, YIELD AND FRUIT QUALITY ON DURIAN

This study was aimed to investigate the effect of uniconazole (UCZ) on inducing early flowering, fruit yield and quality in durian cultivar ‘Monthong’. In the 1st year, a single foliar spray at a high concentration of 2,500 mg L-1 UCZ was made, compared to multiply sprays of 1.5 mg L-1 brown seaweed extracts, a conventionally used solution. The results showed that UCZ sprayed at mature leaf stage after 2nd leaf flushing could hasten flower emergence. UCZ very strongly inhibited inflorescence length, shortening the fruit stalk. There was no significant effect of UCZ on fruit yield but UCZ reduced fruit size. Analysis of fresh fruit showed that UCZ decreased both fresh weight and normal seeds. In vivo pollen germination, observation showed that UCZ delayed pollen tube growth. In the 2nd year, the experiment was conducted to find a suitable concentration for early durian fruiting. Lower concentrations of UCZ could induce both early flowering and more flowering branches than non-chemical application. All lower concentrations of UCZ had no effect on fruit yield. Spraying of 100 mg L-1 UCZ had no effect on suppression of inflorescence elongation and fruit size. UCZ at 250 and 500 mg L-1 inhibited only fruit width, whereas no other fruit size characteristics were suppressed. All lower concentration of UCZ decreased both fresh weight and the number of normal seeds. These results suggest that UCZ promoted flowering in durian by shortening the time of bud release. The reduction of pollen tube growths caused by UCZ could be attributed to the inhibition of normal seed development. We recommended the lower concentration of UCZ at 100 mg L-1 for early durian production.

Plant Growth Retardant Drench Efficacy Is Not Affected by Substrate Containing Parboiled Rice Hulls

Parboiled rice hulls have become a more common component of soilless growing substrates. While there have been reports that some organic substrate components reduce the efficacy of plant growth retardant (PGR) drenches, the influence of rice hulls on PGR drenches is unknown. ‘Callie Deep Yellow’ calibrachoa (Calibrachoa ×hybrid) and ‘Delta Orange Blotch’ pansy (Viola wittrockiana) were planted in containers filled with substrate containing (v/v) 80% peat and 20% perlite or parboiled rice hulls. After planting, 2.5-fl oz drenches containing deionized water or ancymidol, paclobutrazol, or uniconazole were applied to plants grown in each substrate. Plant growth retardants, but not substrate, affected growth rate, and final stem length of calibrachoa and plant height of pansy. There were no differences in regression model coefficients between substrates within PGR applications for plant height (pansy) or stem length (calibrachoa) over the course of the experiment. Paclobutrazol (2.0 or 4.0 ppm) and uniconazole (1.0 or 2.0 ppm), but not ancymidol (1.0 or 2.0 ppm) suppressed final stem length of calibrachoa. Final height of pansy was suppressed by each concentration of paclobutrazol and uniconazole and 2.0 ppm ancymidol, but not 1.0 ppm ancymidol. Based on these results, rice hulls did not reduce PGR drench efficacy when included as a substrate component comprising (v/v) 20% of a substrate.

Vegetative Growth Responses of Citrus Nursery Trees to Various Growth Retardants

As part of a larger study to improve rind color of citrus (Citrus spp.) fruit, this initial study was conducted to determine the concentration of various gibberellin-biosynthesis inhibitors required to elicit a biological response in citrus trees, as measured by vegetative growth. Paclobutrazol and GA3 were included as control treatments at concentrations known to elicit growth-retarding or growth-promoting effects, respectively. Repeated (×4) foliar applications of GA3 (at 64 ppm) increased growth of ‘Eureka’ lemon (Citrus limon) shoots by 63%, with no significant effect on rootstock and scion diameters. Repeated foliar applications of prohexadione-calcium (ProCa) at various concentrations (100, 200, 400, or 800 ppm) as well as uniconazole (at 500 or 1000 ppm) and paclobutrazol (at 0.25%) had no effect on rootstock or scion diameters 8 months after the first application. The high concentrations of ProCa (800 ppm) and uniconazole (1000 ppm), and the paclobutrazol treatment (0.25%) reduced shoot length compared with the control. Uniconazole at 1000 ppm resulted in the most growth retardation, which resulted in 34% shorter shoot length than the control. Although the number of nodes on the longest shoot did not differ from the untreated control, internode length differed significantly among treatments. ProCa at 400 and 800 ppm, uniconazole at 1000 ppm, and paclobutrazol at 0.25% significantly reduced internode length relative to the control by 31%, 56%, 50%, and 28%, respectively. Vegetative growth of ‘Eureka’ lemon nursery trees was retarded following the repeated (×4) foliar application of gibberellin-biosynthesis inhibitors. ProCa at 400 to 800 ppm and uniconazole at 1000 ppm were identified as prospective treatments for further field studies to test their effects on rind color enhancement of citrus fruit.

Effect of Seed Soaking with Uniconazole on Growth and Development of Foxtail Millet Plant

The objective of this study was to investigate the influence and regulation effect of seed soaking with different uniconazole concentrations(15,30,60,and 120 mg L-1) on the growth of roots and relation between roots and shoots in foxtail millet cultivar Jingu 21 cultured in pot and soil column on the experimental farm of Shanxi Agricultural University.The main results were as follows:(1) Uniconazole treatment inhibited the growth of shoots and promoted the growth of roots simultaneously.The number,activity,dry weight and total length of roots increased obviously,so did the stem thickness and tillers,but the plant height decreased.(2) Uniconazole treatment decreased the leaf area at seedling stage,but promoted its leaf growth at booting stage.(3) Uniconazole treatment adjusted the senescent process of plant through prolonging the declining phase of root activity,improving the activities of SOD and POD,and reducing malondialdehyde(MDA) accumulation in root and flag leaf after anthesis to some extent.Through treating seed in 30 mg L-1 uniconazole,the activities roots in lower layer increased 34.95%,43.64%,and 44.74% respectively at 10,20,and 30 days after anthesis compared with control.(4) Uniconazole treatment increased the ears per pot,1000-grain weight,and the yield obviously.In a conclusion,the seed soaking in uniconazole solution of 15-120 mg L-1 concentrations could increase the foxtail millet yield obviously,and the treatment of 30 mg L-1 uniconazole had the best effect under the condition of this study.

Influence of uniconazole and plant density on nitrogen content and grain quality in winter wheat in South China

Superior protein quality and consistent processing quality is needed for winter wheat marketing in South China. It has been shown that uniconazole concentration and plant density are certainly related to crop growth. An experiment was conducted to investigate the effects of uniconazole concentration and plant density on nitrogen content and grain quality in winter wheat (&lt;I&gt;Triticum aestivum&lt;/I&gt; L.). Trials were managed to provide three levels of density (90 × 10&lt;sup&gt;4&lt;/sup&gt;, 180 × 10&lt;sup&gt;4&lt;/sup&gt;, and 270 × 10&lt;sup&gt;4&lt;/sup&gt; per ha) over plots receiving four levels of uniconazole concentrations (0, 10, 20, and 40 mg/kg) which were applied to seeds before sowing. The results revealed that the contents of N accumulated in ear, stem, and leaf were higher in uniconazole concentrations than that in control, and the effect of uniconazole on main stem was bigger than that on tillers. The grain protein was significantly (LSD, &lt;I&gt;P&lt;/I&gt; &lt; 0.05) higher in uniconazole concentrations than that in control. Uniconazole at 20 mg/kg was the most favorable for improving grain protein and protein fractions. Application of uniconazole concentrations also significantly (LSD, &lt;I&gt;P&lt;/I&gt; &lt; 0.05) increased WGC (wet gluten content) and SDS (sedimentation volumes), prolonged DDT (dough development time) and DST (dough stable time), and improved WA (water absorption), increased VV (valorimeter value), and subsequently improved the processing quality of wheat grains. These results suggest that a combination of uniconazole concentration and plant density should be applied in South China.

EFFECTS OF PACLOBUTRAZOL ON GROWTH AND FRUITING CHARACTERISTICS OF ´PITANGA´ ORNAMENTAL PEPPER

Two experiments using container-grown ornamental pepper (Capsicum chinense ‘Pitanga’), were conduced to determine effects of paclobutrazol on growth and fruiting responses. In experiment 1, paclobutrazol was sprayed on the canopy at concentrations of 0; 30; 60; 90; 120 and 150 mg ai⋅L. In experiment 2, paclobutrazol drenches were applied at 0, 5, 10, 15, 30 and 60 mg ai⋅L. Increasing paclobutrazol concentration decreased plant height, plant diameter and plant dry mass but increased leaf chlorophyll content in both experiments. Severe height retardation of plants was evident at 30 and 60 mg ai⋅L in the second experiment, also exhibiting phytotoxicity symptoms. Paclobutrazol treated plants exhibited greener leaves compared to untreated plants. Increasing paclobutrazol foliar application concentrations, the fruit diameter was increased and the fruit weight was unaffected. Considerations of growth and fruiting response should be balanced when using paclobutrazol in ‘Pitanga’ ornamental pepper pot production. INTRODUCTION Brazil has a large genetic diversity of wild peppers but more scientific research is needed to undertanding the growth cycles and cultural requirements of those plants. The use of peppers as ornamental potted plants exhibit advantages like easy seed propagation, short cycle production, heat and drought tolerance, fruit production and excellent postharvest performance (Harbaugh and Waters, 1979). A new genetic access ‘Pitanga’ pepper (Capsicum chinense), catalogued in Germoplasm Bank of Federal University of Vicosa, has potential as an ornamental pot plant, if the growth can be controlled. Application of growth retardants is a common practice for commercial growers to achieve attractive compact pot-grown plants. Researchers have reported that paclobutrazol, a triazole plant growth regulator, is effective in controlling vegetative growth and promoting compactness in the production of a number of ornamental plants including Chrysanthemum morifolium (Barret, 1982; Zalewska, 1989), Lilium longiflorum (Jiao et al. 1986), Euphorbia pulcherrima (Goulston and Shearing, 1985) and Tulips (McDaniel, 1990). Starman (1993) investigated the effects of different concentrations of uniconazole, another triazole plant growth regulator, on controlling growth and fruiting of ‘Holiday Cheer’ Capsicum annuum. Concentrations ranging from 5.0 to 15.0 mg•L gave adequade height control. Triazoles are generally more effective in retarding growth when applied to the soil or directly to stems compared to foliar applications (Davis et al., 1988). However, foliar and drench paclobutrazol applications have been studied on growth control of ornamental plant production (Anderson and Hartley, 1990; Banon et al., 2002). Despite the use of paclobutrazol in the industry of potted plants, few studies have been published concerning paclobutrazol efficacy for ornamental peppers. Also, evaluation of the effect of paclobutrazol on growth and fruiting characteristics of ‘Pitanga’ ornamental pepper has not been reported. The objective of this study was to investigate the effects of paclobutrazol on growth and fruiting characteristics of ‘Pitanga’ ornamental pepper. Proc. V IS on New Flor. Crops Eds.: A.F.C. Tombolato and G.M. Dias-Tagliacozzo Acta Hort. 683, ISHS 2005