Ppm Gibberellic Acid Research Articles

Factors affecting germination of Myricagale seeds

Several factors affecting seed germination were investigated in Myricagale L., a nitrogen fixing shrub common on wet soils. Light was essential: seeds failed to germinate in the dark and required four 16-h photoperiods (one per day) for maximum germination. There was no absolute requirement for prechilling, but prechilling increased germination by 75% in 2-month-old seeds and by 164% in 4.5 year-old seeds. Leaching did not affect germination and 500 ppm gibberellic acid enhanced germination only 20%. The seeds were long-lived: there was no decrease in percent germination during 6 years of dry storage at 5 °C and germination remained high after 1 year of wet storage at 5 °C. Because M. gale seeds often germinate on water-worked substrates, the requirement for extended exposure to light for germination may serve as a mechanism to prevent unsuccessful germination of seeds that are reburied after brief exposure to light as sediments are worked by water.

Effect of Gibberellic Acid on Flowering and Quality of Double Persian Violet

Abstract Three experiments were conducted with double-flowering Persian violet (Exacum affine Balf.) to evaluate the effet of gibberellic acid (GA) applied at different flower bud sizes, developmental stages (ages) of the plant, and application frequencies. In Expt. 1, the greatest number of flowers was produced in plants with 8-mm bud size, with the largest flower diameter obtained with 4-mm bud size. Treatment with GA increased the number of flowers. Flower diameter was greatest with a GA concentration of 125 ppm. Plant quality of GA-treated plants was best when sprayed at 8-mm bud size with a concentration of 125 ppm. In Expt. 2, plants treated at 12 weeks after transplanting had the most flowers. Flower diameter decreased for all treated plants and all age groups in comparison with non treated plants. GA at 125 ppm produced the largest increase in number of flowers and maintained a large flower diameter. Plants treated 8 weeks after transplanting with 125 ppm GA had the most desirable plant size and flowering characteristics. In Expt. 3, a single application of 125 ppm GA was the most effective in contrast to multiple applications for flower induction, number of flowers, and flower diameter.

Growth regulators, photoperiod, and flowering in potatoes

The effect of 25 ppm gibberellic acid (GA3), 7,500 ppm Gapol(R) (0.4% molybdate; 0.42% cobalt; 0.56% tungstate; 2.84% borax; 4 ppm indoleacetic acid; 4 ppm naphthyltalamic acid; and 2 ppm ethylenediaminetetraacetic acid) and of two photoperiods (12 and 18 h daily) on flowering of potato cv Marijke was studied under greenhouse conditions. GA3 specifically reduced the number of days required for flowering, and Gapol(R), or long days, favored bud retention. When combined, only a slight additive effect was observed. In most cases spraying the products on plants subjected to long days resulted in an increase in the number of floral buds, but their attachment to the plant was mainly influenced by the presence of Gapol(R).

Intersubgeneric Crossability in the Genus Glycine Willd.

AbstractIn intersubgeneric crosses between wild perennial Glycine species of submenus Glycine and soybeans, Glycine max (L.) Merr., of subgenus Soja, all the putative hybrid pods aborted from 9 to 30 days after pollination (DAP). Spraying of 70 ppm gibberellic acid on hybridized gynoecia facilitated pod retention. Fluorescence microscopy revealed normal pollen germination and pollen tube growth in all the intersubgeneric crosses except in the G. cyrtoloba × G. max cross.

Effect of Foliar- and Soil Surface-applied Paclobutrazol on Vegetative Growth and Fruit Quality of Sweet Cherries

Abstract The length of the lag phase following treatment and the persistence of the eventual growth suppression effect of 1.15 g paclobutrazol (PBZ) per tree declined as the area of treated soil surface beneath the tree increased. Treating one side of the tree row was as effective as treating both sides, but immediately adjacent “control” trees were largely unaffected by these soil-surface treatments. In a 2nd experiment, single, or multiple sprays applying the same amount of chemical in total gave equal growth control in the season of application, but residual growth control was slightly superior on trees sprayed four or 10 times. All PBZ treatments advanced anthesis but failed to improve flower number or fruit set. The weight of individual cherries was increased in each of the three years following the soil-surface application of PBZ, but, except for a reduction in soluble solids, fruit quality was unaffected. Foliar sprays of PBZ in 1984 led to larger fruit size in 1985, but fruit coloring was delayed and soluble solids were reduced. A preharvest spray of 20 ppm gibberellic acid (GA3) substantially enhanced the PBZ effect on fruit size and color but also increased fruit firmness, juice acidity, stem length, and fruit removal force and reduced the incidence and severity of pitting following 2 weeks of cold storage. Chemical names used: β-[(4-chlorophenyl)methyl]-α-(1,1-dimethylethyl)-1H-1,2,4-triazole-1-ethanol (paclobutrazol).

Improving Germination of Papaya Seed by Density Separation, Potassium Nitrate, and Gibberellic Acid

Abstract Poor germination in Carica papaya L. was partly due to the absence of embryos in about 20% of the seeds. Final germination and the rate of seedling emergence were improved by seed separation with 1.097 g·em−3 sucrose solution and soaking with 1.0 M potassium nitrate (KNO3) or 600 ppm gibberellic acid (GA3). Final germination was 87.8% for the KNO3 treatment and 80.5% for GA3. Seedlings from KNO3 treatments were normal, whereas GA3 caused excessive elongation of stems.

Effect of Chemicals and Photoperiod on the Growth and Flowering of Thanksgiving Cactus

Abstract Schlumbergera truncata (Haw.) Moran ‘Christmas Charm’, ‘Lavender Doll’, and ‘White Christmas’ were grown under an 8 hr natural photoperiod or an 8 hr natural photoperiod plus 4 hr of incandescent light from 10:00 pm to 2:00 am and treated with single sprays of BA at 100 and 200 ppm, GA at 25, 50, and 100 ppm, BA at 100 and 200 ppm plus GA at 25 or 100 ppm, calcium carbide at 2910 ppm, ethephon at 100 and 1000 ppm, daminozide at 5000 ppm, ancymidol at 132 ppm, and chlormequat at 1000 ppm in 2 experiments. No flower buds were initiated from any plants grown under the 8 + 4 hr photoperiod. BA applied at 100 and 200 ppm increased the number of phylloclades on ‘Christmas Charm’ plants grown under the 8 + 4 hr. BA at 200 ppm applied to plants grown under the 8 hr photoperiod caused an increase in flower bud number and earlier flowering in all cultivars tested. BA + 100 or 200 ppm 100 ppm GA applied to plants grown under the 8 hr + 4 hr photoperiod stimulated the growth and elongation of phylloclades. Applied to plants grown under the 8 hr photoperiod, BA plus GA caused the growth and elongation of phylloclades, initiation of lower buds, and induced the development of lateral phylloclades and flower buds. Ancymidol at 132 ppm and 1000 ppm chlormequat sprays produced earlier flower bud initiation and increased flower number to flower bud ratios on ‘Christmas Charm’ plants. Chemical names used: N-(phenylmethyl)-H-purin-6-amine (BA); gibberellic acid (GA); (2-chloroethyl)phosphonic acid (ethephon); butanedioic acid mono(2,2-dimethylhydrazide) (daminozide); α-cycloproply-α-4-methoxyphenyl)-5-pyrimidinemethanol) (ancymidol).

Forçamento de brotação em batata cultivar Aracy (IAC-2) para o teste de pré-cultura

A implantação do teste da pré-cultura é condição necessária para a melhoria da certificação da batata-semente no Brasil. Esse teste permite o aprimoramento da determinação da sanidade do material produzido, principalmente no tocante à porcentagem de plantas contaminadas pelo vírus do enrolamento da folha da batata (VEFB), um dos principais fatores limitantes da produção de batata-semente, e de outros problemas fitossanitários transmissíveis pelo tubérculo. Um dos principais pontos de restrição a seu emprego é o tempo necessário para a obtenção de leitura final efetiva. Para determinar o melhor método de forçamento de gemas que permitisse a leitura final, foi realizado em 1983, no município de Tietê (SP), um ensaio com diferentes métodos de forçamento, empregando o cultivar Aracy (IAC-2), proveniente de campo com cerca de 20% de infecção do tubérculo-mãe pelo VEFB. Os tratamentos utilizados foram os seguintes: (1) testemunha; (2) tratamento de tubérculos com CS2, 30cm³/m³ de câmara, durante 48h; (3) imersão de gemas em solução contendo 1 ppm de ácido giberélico por 10 minutos; (4) idem, solução contendo 2ppm; (5) tratamento 2 + tratamento 3; (6) tratamento 2 + tratamento 4. Foram realizadas cinco observações, até 50 dias após o plantio, dos seguintes pontos: porcentagem de emergência, altura das plantas, número de folhas na haste principal e de hastes por gema, porcentagem de VEFB e facilidade de leitura. O plantio foi realizado em canteiros, com terra esterilizada, plantando gemas em espaçamento de 0,25 x 0,10 cm. Os tratamentos que propiciaram germinação precoce foram os que utilizaram a combinação dos dois produtos (CS2 e ácido giberélico), sendo a diferença diminuída no decorrer das leituras. O tratamento 5 apresentou plantas em condições ideais de leitura num período de tempo mais curto.

The Response of Wild Oat (Avena fatua) andAvena sterilisAccessions to Photoperiod and Temperature

Twenty-nine wild oat (Avena fatuaL. ♯3AVEFA) andAvena sterilisL. ♯ AVEST accessions having various areas of origin and/or growth characteristics were grown to maturity in controlled environmental chambers. The four environments consisted of a 16-h photoperiod until 3 weeks after emergence, when the photoperiod was decreased (DP) 1 h per week for 8 weeks at a constant 14, 20, or 26 C (DP 14, DP 20, or DP 26); and an 8-h photoperiod until 3 weeks after emergence, when the photoperiod was increased (IP) 1 h per week for 8 weeks at a constant 20 C (IP 20). The relative growth rate of the accessions was similar in each environment. The length of the second leaf was up to 15 cm greater under 8- than 16-h day length at 20 C for some accessions, but was similar under both day lengths for other accessions. The width of the second leaf was greater under 14 than 20 C and was narrower with a 16-h than an 8-h photoperiod. Tiller initiation was slower in the DP 14 and IP 20 than in the DP 20 and DP 26 environments. Days to panicle emergence for individual accessions ranged from 10 to 57 days higher in the DP 14 than in the DP 20 environment. Seed produced on plants grown at 14 C had lower germination in water and 1500 ppm gibberellic acid than seed from plants grown at 20 C. Wild oat accessions varied in morphological characteristics, days to panicle emergence, and dormancy, and responded differently to changes in photoperiod and temperature. Wild oat morphological characteristics, days to panicle emergence, and dormancy did not consistently relate to species or area of origin.

Growth Regulators, Fruit Drop, Yield, and Quality of Navel Orange in Florida

Abstract Fruit drop of navel orange [Citrus sinensis (L.) Osbeck], which occurs after June drop, was studied from 1980 through 1982 in 2 groves in north-central Florida. Summer drop, which occurs from June to August, and summer-fall drop, which occurs from late August through October, were the major periods of fruit drop. Fruit drop was significant in 1981, ranging from 63 to 200 fruit per tree. A dilute spray of 10 or 20 ppm 2,4-dichlorophenoxyacetic acid (2,4-D), alone or in combination with 20 ppm gibberellic acid (GA) and applied 5 to 9 weeks after midbloom, reduced summer fruit drop in all seasons. The same materials applied 13 weeks after midbloom were ineffective. An application of 2,4-D at 5 weeks after midbloom increased yields in 1981, but not in 1982, because summer drop was minor in that year. Midbloom application of GA + 2,4-D increased splitting and summer-fall drop in 1981, but generally these materials had no effect. Sprays of 2,4-D, GA, or the combination did not adversely affect internal fruit quality, although GA or GA + 2,4-D increased rind firmness when applied 13 weeks after midbloom.

Malting of Triticum dicoccum (Khapli) Wheat: Response to Gibberellic Acid and Use in Baking

ABSTRACT T. dicoccum malt developed high amylolytic and proteolytic activity by applying 0.25 and 0.50 ppm gibberellic acid (GA) and germination for 5 and 7 days at 20°C. The 5‐ and 7‐day malts without GA showed an alpha‐amylase activity (SKB/g) of 73.7 and 99.2, respectively, which was increased to 183.5 and 193.1 by 0.5 ppm of GA treatment. Kolbach Index values of 61.7 and 65.2% of GA malts indicated high modification with conversion times of >1 min. Phytic P decreased from 80.5% in wheat to 41.2–53.4% in malts. Increased volume and softer crumb were characteristic of loaves made with 10 SKB of malt per 100g flour without sugar in the formula.

Effect of Gibberellic Acid on Yield and Quality of Fall-harvested and Overwintered Spinach

Abstract A single application of 20 ppm gibberellic acid (GA3) 2 weeks before harvest increased yields and height of fall spinach (Spinacia oleracea L.) by inducing the setting of leaves in an upright position and stimulating petiole and stem growth. Small differences were noted between GA3-treated and untreated overwintered spinach. Cultivars responded similarly to growth conditions and to GA3 application. Both GA3-treated and untreated fall spinach had better quality than overwintered spinach harvested in the spring. Spinach treated with GA3 had higher shearpress values, yellow and green color, lower titratable acidity, and no change in pH values as compared to the control. A panel graded GA3-treated spinach slightly higher in amount of petioles and stems and lower in general acceptability than the untreated control. Better utilization of GA3 was obtained in the fall-grown spinach.

Gibberellic Acid-induced Fruiting of Lingonberries, Vaccinium vitis-idaea L. ssp. minus (Lodd.) Hult.1

Abstract A single application of 50, 100 or 500 mg/liter gibberellic acid (GA) during 75% full bloom induced seedless fruit development in lingonberries growing in their native habitat in Alaska. Fruit set was increased by the 500 ppm GA treatment in the absence of insect pollination. Fruit set was not increased by GA in open-pollinated plants. Berry weight and diameter were unaffected by GA treatments.

Off-season Bloom in ‘Temple’ Orange Repressed by Gibberellin1

Abstract One early treatment (late May) with 25 ppm gibberellic acid (GA3) strongly depressed summer and fall bloom and resulting off-season fruits of ‘Temple’ orange (Citrus reticulata Blanco × C. sinensis (L.) osbeck). A late June treatment failed to repress and even tended to increase the number of off-season fruits. A repeated treatment at both dates, had a smaller effect than a single early treatment. A possible effect of a late GA application on the persistence of off-season fruitlets is suggested. Girdling of a part of scaffold branches gave a response similar to that of the early GA treatment.

Effect of Temperature, Fall Defoliation, and Gibberellic Acid on the Rest Period of Peach Leaf Buds1

Abstract Temperature treatments influenced inception, intensity and termination of rest in peach trees [Prunus persica (L.) Batsch]. A substance that affected the response was translocated within the trees. The time of leaf abscission in the fall was related to duration and intensity of rest in ‘Gleason Elberta’ peach leaf terminal buds. An August application of 100 ppm gibberellic acid (GA3) and warm field temperatures delayed defoliation and extended rest.

Effect of foliar application of antibiotics and gibberellic acid on the rhizosphre microflora of pea, infected with Verticillium dahliae.

A study was made of the effects of foliar spray of bacitracin, chloramphenicol and gibberellic acid on the rhizosphere microflora of pea seedlings (Pisum sativum L.) infected with Verticillium dahliae. The antibiotics increased fungus and actinomycete counts and reduced the bacterial populations in the rhizosphere. Gibberellic acid at 10 ppm concentration reduced all three groups of microorganisms while at 100 ppm fungi and actinomycetes increased slightly. Invariably the rhizosphere effect was as follows: bacteria leads to fungi leads to actinomycetes. Foliar sprays also affected percentage occurrence of particular genera of fungi in the rhizosphere; for example, Trichoderma spp. were stimulated by all the treatments, the maximum being with 10 ppm gibberellic acid, even though the total fungus count was reduced. The disease severity was markedly reduced by foliar sprays.

Accelerating Palm Seed Germination with Gibberellic Acid, Scarification, and Bottom Heat1

Abstract Scarification and pre-soak treatments with water or 1000 ppm gibberellic acid (GA) accelerated seed germination of Alexandra palm [Archontophoenix alexandrae (F. J. Muell.) H. Wendl. & Drude]. Macarthur palm [Ptychosperma macarthurii (H. Wendl.) Nichols] germination was accelerated following scarification or pre-soaking in 1000 ppm GA, however, in both species greatest acceleration was obtained when the scarification and GA treatments were combined. Germination time of Macarthur palm was also reduced by 6 weeks when sown in beds heated to 27° ± 1°C.

Effect of Depulping and Growth Regulators on Seed Germination of Alyxia olivaeformis1

Abstract Seed germination rate and percentage of maile (Alyxia olivaeformis Gaud.) were improved by removal of the fleshy seed coat and preconditioning with growth regulators. Preplant soaking for 48 or 72 hours with 100 ppm kinetin, 2000 ppm potassium nitrate (KNO3), 500 ppm or 1000 ppm gibberellic acid (GA) were the most effective treatments.

Effects of Gibberellic Acid and Ethephon on Enzymatic Browning of ‘Redhaven’ Peaches1

Abstract Trees of ‘Redhaven’ peach (Prunus persica (L.) Batsch) were sprayed with 100 ppm gibberellic acid (GA) or 75 or 150 ppm (2-chloroethyl)phosphonic acid (ethephon) 21 or 46 days after full bloom and the ripe fruits were evaluated for enzymatic browning. Treated fruit had less browning than untreated fruit and fruit treated 46 days after bloom had less browning than fruit treated 21 days after bloom. Purees from ethephon treated fruit had higher pH values than those from GA treated fruit. Fresh weight of ethephon treated fruit varied with ethephon concentration and time of application. Polyphenoloxidase (PPO) activity and o-diphenol content were not affected by treatment. Multiple regression analysis indicated that 81% of the variation in browning was explained by variations in treatment, treatment application date, o-diphenol content, PPO activity and fresh weight.

Efeitos da vernalização e de fitoreguladores no desenvolvimento de Lilium longiflorum Thunb

Bulbos de lírio foram mantidos a 22°C ou vernalizados a 4º ou 8°C por duas semanas, sendo então imersos por 12 horas em soluções de ácido giberélico (GA) 1000 ppm ou ácido indolilacético (IAA) 1000 ppm, antes de serem plantados em condições de campo. Tratamento dos bulbos a 4°C, durante duas semanas, atrasou a emergência das brotações. Este atraso devido a vernalização foi removido quando os bulbos foram imersos por 12 horas em soluções de GA ou IAA 1000 ppm. Vernalização e fitoreguladores não afetaram a altura nem a qualidade das plantas de lírio. A vernalização dos bulbos a 4º ou 8°C, durante duas semanas, reduziu o número de hastes produzidas. Nao se verificaram diferenças entre os tratamentos em relação ao período de tempo para a ocorrência da antese floral. A qualidade da inflorescência foi melhorada pela vernalização do bulbo a 8°C durante duas semanas ou por imersão durante 12 horas em solução de IAA 1000 ppm.