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1.
The response of Mid-Century Hybrid lily ‘Enchantment’ to ancymidol has been investigated in two experiments. In the first, three dates of application were employed, the earliest at inflorescence initiation, the second and third 10 and 20 days later, respectively. Application (750 μg/plant as a 15 ppm soil drench) on the second date produced the shortest plants, a result attributed to more extensive uptake by a better-developed root system. Plants subjected to treatment on the third date were, by then, too tall for the maximum dwarfing effect to occur. Flower number was unaffected by treatment, but ancymidol delayed anthesis by between 4 and 6 days and promoted earlier senescence of basal leaves.In the second experiment, interactions between gibberellic acid (GA3) and ancymidol were demonstrated. Increasing amounts of GA3 (20, 200 and 2 000 μg/plant as aqueous applications to the shoot tip) progressively counteracted the dwarfing effect of ancymidol (500 μg/plant as a 10 ppm soil drench) and, in the absence of ancymidol, 2 000 μg GA3/plant significantly promoted stem extension. Flower number was slightly decreased by GA3 in the absence of ancymidol. An ancymidol-induced delay in anthesis of almost 5 days was progressively reduced by increasing levels of GA3, which, in the absence of ancymidol, did not significantly influence the time of anthesis. Applied separately, neither ancymidol nor GA3 significantly affected pedicel length of the first flower, but increasing levels of GA3 progressively promoted pedicel elongation in the presence of ancymidol.  相似文献   

2.
Single spray applications of 100 ppm of a mixture of the gibberellins A4 and A7 (GA4 + 7) were made on fruiting spurs of the apple cultivar Cox's Orange Pippin to investigate the effect on set, June drop and growth of fruits, as well as on shoot development and flower-bud formation on the bourses. Applications were made from 1 to 50 days after full bloom following partial hand-pollination of flowers, i.e. two stigmas per flower pollinated. In another experiment applications were made from 1 to 20 days after full bloom following complete (five stigmas per flower) or partial (two stigmas per flower) hand-pollination, after open pollination, or on emasculated flowers.GA4 + 7 only temporarily increased fruit set after open pollination or after effemination of flowers, and then only after application 1 day after full bloom. GA4 + 7 did not affect the very high fruit set after complete or partial hand-pollination. Both latter pollination treatments induced an equally high fruit set.GA4 + 7 reduced June drop significantly whenever fruits were left after first drop, except after early applications following open pollination. GA4 + 7 was effective in June-drop reduction up to 40 days after full bloom, i.e. until the onset of the June drop.Fruit size was not clearly affected by GA4 + 7. The smaller fruits obtained in some cases after GA treatment could be explained by assuming that maturity was reached by fruits that would have abscised without an exogenous GA4 + 7 supply. GA4 + 7 also increased seed abortion. Fruit length was increased by GA4 + 7 only for applications made up to 20 days after full bloom.GA4 + 7 stimulated bourse-shoot development to some extent. Flower-bud formation on the bourses was not clearly affected by GA4 + 7, but was markedly influenced by the presence of fruits.That GA4 + 7 reduced June drop so much in spite of a slight promotive effect on bourse-shoot growth and a slight abortive action on seeds suggests that these gibberellins may be specific stimuli for apple-fruit growth after actual fruit set is achieved.  相似文献   

3.
The effect of Prohexadione Calcium (Pro-Ca) and daminozide was observed on the growth characteristics and endogenous gibberellin contents of Chrysanthemum morifolium R. cv Monalisa White. Three concentrations viz. 100, 200 and 400 ppm of Pro-Ca and a single concentration of daminozide (800 ppm) were applied three times with 7 days interval on three weeks old plant under greenhouse condition. Pro-Ca suppressed the plant length up to 30.7% while daminozide inhibited up to 27.12% at optimum concentration. The chlorophyll contents and stem diameter were higher than control, while the fresh weight and flower number insignificantly reduced with such treatments. Gibberellin (GA) analysis showed that Pro-Ca and daminozide application significantly lowered bioactive GA1 content, although the amount of its immediate precursor GA20 was fractionally higher. Bioactive GA4 content was slightly higher than the control while significant difference in GA9 was found between the plants treated with Pro-Ca and daminozide. Current study showed that both early C13 hydroxylation and non-C13 hydroxylation pathways of GA biosynthesis are operational in C. morifolium.  相似文献   

4.
In vegetatively propagated Pelargonium × hortorum plants, formation of axillary shoots and initiation of inflorescences and leaves were promoted by an increase in quantum flux density, whereas application of GA3 had a negative effect. Application of CCC caused an increase in number of axillary shoots and consequently an increase in number of inflorescences and leaves per plant.Dry weight increase was promoted by an increase in quantum flux density, unaffected by GA3 treatment, but inhibited by CCC treatment. Moreover, continuous removal of the oldest leaves reduced the number of inflorescences, leaves, axillary shoots and dry weight. The changes in inflorescence and leaf initiation could not be definitely correlated to the changes in dry weight increase.  相似文献   

5.
The effect of 50% shading and NO3:NH4 ratio (0:100, 75:25, 50:50, and 25:75) in the nutrient solution on growth, yield, quality and N metabolism in hydroponically grown strawberry (Fragaria × ananassa var Camarosa) was evaluated. Both fresh and dry weights of leaves were significantly lower when a high concentration of either NO3 (100%) or NH4 (75%) was the sole N source in the nutrient solution. In unshaded plants, increasing of both NH4 and NO3 ratio in the nutrient solution reduced photosynthetic (Pn) rate, however in shaded plants the reduction of Pn became more pronounced at a higher ratio of NH4 in the nutrient solution. The yield in terms of fresh and dry weight of fruit per plant was significantly increased at the 75:25 and 50:50 (NO3:NH4) treatments. Fruit size was significantly affected by the treatments, so that the biggest fruits in both shaded and unshaded plants were obtained under the 75:25 and 50:50 (NO3:NH4) treatments. Total soluble solid (TSS) in unshaded plants was increased with increasing NH4 ratio in the nutrient solution, however in shaded plants it was reduced at high NH4 ratio in the nutrient solution. In both shaded and unshaded plants, higher concentration of NH4 significantly reduced the post-harvest life of the fruits. The increase of tissue N concentration was nearly proportional to the NH4 concentration in the nutrient solution. The activity of nitrate reductase (NR) was increased by increasing NH4 from 0 to 50% and then reduced at a higher ratio of NH4 in the solution. Shading increased NH4 concentration so that the shaded plant had nearly twice as high NH4 concentration in the leaves. The increase of NH4 concentration induced by shading could be partially the reduction of NH4 assimilate because of the shortage of carbohydrate.  相似文献   

6.
The effect of GA3 15 mg l?1, Planofix (NAA = 1-naphthalene acetic acid) 300 mg l?1 and Ethrel 250 mg l?1 on granulation and fruit quality in ‘Kaula’ mandarin (Citrus recticulata Blanco) was studied during 1975–1976. Three sprays of Planofix reduced the incidence of granulation to 30.7% from 62.7% in control. Three sprays of GA3 were almost equally effective (31.3% granulation). These treatments also improved the fruit quality and gave the highest fruit weight, pulp percentage, juice, T.S.S., reducing and non-reducing sugars and ascorbic acid, and the lowest acidity, peel and rag. In both these treatments (3 sprays of GA3 or Planofix) the T.S.S. was 9.3% (8.1% in control). The application of 3 sprays of Planofix 300 mg l?1 or GA3 15 mg l?1 is, therefore, considered to be successful in reducing the granulation in this cultivar of mandarin.  相似文献   

7.
GA3 induced stem elongation and had no effect on leaf area, whereas CCC and B-9 reduced those characteristics. All 3 growth substances increased leaf formation. GA3 and CCC accelerated the beginning and duration of blooming, but B-9 exhibited the opposite trend. Inflorescence formation was promoted by CCC and B-9 and decreased by GA3. Stalk length of inflorescences was elongated only by GA3 and dwarfed by CCC and B-9. Carbohydrate fractions and content of anthocyanin in flowers were promoted by CCC and B-9.  相似文献   

8.
To investigate whether GA3 can substitute for the requirement, 1 mg GA3 was injected in dry stored bulbs before, during or after the following treatments: (a) 12 weeks at 21°C, (b) 12 weeks at 5°C, (c) 6 weeks at 21°C followed by 6 weeks at 5°C, and (d) 6 weeks at 5°C followed by 6 weeks at 21°C. The bulbs were then planted in light at 15°C. Plants from bulbs previously subjected to (d) flowered earlier than bulbs from treatments (a) and (c) but later than those subjected to (b). Both the GA3 and the 5°C treatments shortened the time from planting until flowering; however, GA3 produced shorter plants and induced the formation of parthenocarpic fruits. Reduction of scape length by GA3 was less when it was given at a later time during treatments (a) and (c) whereas the scape lengths of bulbs subjected to treatments (b) and (d) were hardly affected by the time chosen for GA3 application.  相似文献   

9.
Effects of treatments with gibberellic acid (GA3, 50 mg L−1 for 2 h) or carbon disulphide (CS2, 25 ml m−3 for four days) on breaking of dormancy and sprouting of potato (Solanum tuberosum L., cvs Agria and Marfona) minitubers of different weight classes (0.3, 0.7 and 1.5 g) were investigated. The dormancy period tended to decrease with an increase in the weight of minitubers, whereas the number of sprouts per minituber, their length and fresh weight and the sprout mass per unit of sprout length of the longest sprout tended to increase with an increase in minituber weight. In both cultivars, applying GA3 or CS2 advanced breaking of dormancy, but GA3 was less effective in Marfona than in Agria. Advancing breaking of dormancy was associated with removal of apical dominance and therefore applying GA3 or CS2 also increased the number of sprouts per minituber, especially in Agria. In Agria, the dry matter content of sprouts from the CS2 treatment was higher than in the GA3 or control treatments, whereas in Marfona dry matter content of sprouts was highest in the GA3 treatment. The length of sprouts, fresh weight of sprouts and the sprout mass per unit of sprout length of the longest sprout were significantly enhanced by treating minitubers with GA3 or CS2 compared with the untreated control minitubers, but there were strong interactions with cultivar and minituber weight. These interactions are important in practical use of dormancy breaking methods.  相似文献   

10.
GA3 sprayed on celery plants, which received a continuous supply of 0, 0.2, 0.4, 0.6 or 1.0% NaCl solutions to the roots, caused a pronounced increase in leaf elongation.Along with enhanced elongation, GA3 increased breakdown of parenchymatous tissue in the petiole, but this effect was drastically suppressed in the salt-treated plants. In a similar fashion, the effect of GA3 on the elongation of the flowering-stem (bolting) was significantly diminished in salt-treated plants. In no case did the salinity treatment totally abolish the bolting-process induced by GA3.Changing the temperature of the lower part of the root system altered the magnitude of GA3 effect on bolting. As the temperature was lowered from 30 to 6° C, the ability of GA3 to cause bolting was greatly reduced.The results are discussed in view of the possible interaction between salinity and the GA3 effect on petiole elongation, cellular breakdown and bolting.  相似文献   

11.
Globe artichoke has important nutritional values related to its high content of phenolic compounds such as cynarin and chlorogenic acid. Cynarin (1,5-dicaffeoylquinic acid) is a derivative of caffeic acid and has effect on hepatobiliary diseases, hyperlipidaemia, dropsy, rheumatism and cholesterol metabolism. The effect of gibberellic acid (GA3) on the yield of the phenolics, chlorogenic acid and cynarin, both in leaves and in the edible part of the head of globe artichoke, were studied. Plant samples were collected for chemical analyses at the laboratories of the Chair of Vegetable Science, Department for Plant Sciences, Technische Universität München in Freising-Weihenstephan, Germany. GA3 at 60 ppm was applied either at 4, 6 or 8 weeks after transplanting date (ATD). When transplant were used, application of GA3 at 4 weeks ATD significantly increased the content of chlorogenic acid in leaves while the level of cynarin was similar to the untreated control. In contrast when plants were direct seeded into the field, GA3 treatments had no affect on phenolics in leaves compared to the untreated control. Whereas GA3 reduced the time to flowering, it did not increase the content of chlorogenic acid or cynarin in leaves or in most of the flower receptacles, except when GA3 was applied at 6 or 8 weeks. On the other hand, cynarin yield in the 3rd–5th harvested flower heads was higher than controls. The timing of GA3 application is, thus, critical for decreasing time to flower as well as altering the content of cynarin and chlorogenic acid in globe artichoke.  相似文献   

12.
Summary

Beneh (Pistacia mutica F. & M.) and kolkhong (Pistacia khinjuk Stock) are wild species of pistachio which grow naturally with other trees in some parts of Iran. Because of their adaptibility to severe environmental conditions and their resistance to some pests and diseases, they can be used as rootstocks for pistachio cultivars. Poor germination and very low seedling vigour of these two species have been a major problem in using them as rootstocks for pistachio cultivars. In this study gibberellic acid (GA3), at five concentrations (100, 250, 500, 750 and 1000 mg l21), were used during and after stratification to enhance seedling growth. The results showed that GA3, applied during and after stratification, significantly increased the length, trunk diameter, internode length, leaf area and fresh and dry weight of seedlings of both beneh and kolkhong species. However, application of GA3 after stratification was more effective on seedling growth of beneh. GA3 applied at higher concentrations (500 and 750 mg l21) increased the rate of growth, but growth malformations were clearly evident in seedlings of kolkhong. GA3 at 250 mg l21 enhanced seedlings growth of kolkhong. It was concluded that application of GA3 to the seedlings might be a useful method for promoting rapid shoot growth of beneh and kolkhong and reduce the expense of seedling production in glasshouse conditions.  相似文献   

13.
We established the conditions to micropropagate the ornamental prickly pear cactus Opuntia lanigera Salm–Dyck through axillary shoot development from isolated areoles. For the shoot proliferation stage different explant orientation (vertical and horizontal), type of cytokinin (BA, DAP and K), and concentrations (0, 1.25, 2,5, 5.0 and 7.5 mg/L) were evaluated. Media [Murashige, T., Skoog, F., 1962. A revised medium for rapid growth and bioassays with tobacco cultures. Phys. Plant. 15, 473–497: 50 and 100%], and carbohydrate concentration (0.25, 0.5, 0.75 and 1.0%) were studied to optimize individual shoot growth and elongation. Following micropropagation and plantlet acclimatization, the effects of GA3 on plant growth were determined by spraying a series of increasing concentrations (0, 150, 300 and 450 ppm). A reliable and efficient protocol of micropropagation was established for this particular plant species. The greatest propagation ratio (shoot proliferation) was obtained when explants were cultured in vertical orientation (4.975 shoots per explant) as compared to horizontal position (3.692 shoots per explant). The addition of BA to the media resulted in increased shoot number per explant (8) in comparison to K and DA, which produced only 2 shoots in average. However, after 42 days of culture, significantly higher shoot length was obtained with DAP (14 mm) compared to K and BA (4 mm). After the shoot proliferation stage, an elongation subculture was performed prior rooting in which shoot growth was enhanced when crowns of shoots were cultured in 50% of basal salt formulation of Murashige and Skoog (1962) and low sucrose concentration (2.5 and 5%). Exogenous application of GA3 after plantlet acclimatization on glasshouse conditions increased spine-hair (developed from areoles in young plants) length as part of short-term effects. However, significantly higher values were obtained in plantlets treated with 300 ppm of GA3 when compared with the rest of the treatments. At the end of the study, the most important long-term effect produced by GA3 was the suppression of total shoot growth. The micropropagation protocol described here and the conditions to grow the plants through fertigation plus the application of GA3 that induced changes in the phenotype may be used in commercial exploitations to regenerate 12,500 plantelts in average after 12 months of culture and produce healthy plants with better ornamental characteristics and higher commercial value.  相似文献   

14.
Partly cooled (5°C) tulip ‘Apeldoorn’ were treated with gibberellins GA3 and GA4 + 7 by vacuùm infiltration, with a view to defining conditions suitable for exploiting the effects of GA on forced tulips (faster flowering, control of stem extension, reduction of floral bud blasting).The first experiment showed that GA3 and GA4 + 7 were equally effective in reducing the glasshouse period following 6 or more weeks cold storage; with less than 6 weeks cold storage, effects were less marked. Stem length at flowering was reduced by GA treatments, particularly by GA3 and following more than 6 weeks cold storage. However, the vacuum infiltration method used (30 min at 10 torr) resulted in serious flower losses.Next, the effect of GA3 concentration (up to 1500 mg 1?1) was studied using vacuum infiltration treatments for 1–15 min at 20–510 torr, which resulted in fewer flower losses. Following 4 weeks cold storage, reducing pressure or increasing GA3 concentration reduced both glasshouse period and stem length, with no effect of duration of treatment; GA3 concentration was the only factor affecting flower length, which was increased. Following 8 weeks cold storage, increasing GA3 concentration, vacuum or duration reduced glasshouse period. With all 3 factors at their maximum levels, 16 days earliness was obtained compared with controls. With maximum earliness, stem length was reduced to about 23 cm, compared to about 26 cm for treatments giving about 1 week's earliness, and 32 cm for untreated controls. Increasing vacuum appeared the most economical way of obtaining earliness, 20 torr giving 7 days earliness even at only 250 mg GA3 1?1. Treatments giving earlier flowering also gave larger flowers. For comparison, there was little effect of soaking bulbs at atmospheric pressure even at 500 mg GA3 1?1 for up to 20 h.Further experiments, conducted with vacuum infiltration at 260 torr for 15 min, confirmed these GA effects using formulated GA3 (as “Berelex”) and GA4 + 7 (as “Regulex”). Effects of GA on stem length at flowering had disappeared by the time stems reached their final length. Comparisons with bulb injection of GA showed that this method required less GA than vacuum infiltration for similar effects, and that the greater effectiveness of GA4 + 7 compared with GA3 was less marked using vacuum infiltration.  相似文献   

15.
Net photosynthesis of tomato plants was measured as CO2 uptake in various light intensities, CO2 concentrations, O2 concentrations and temperatures during short-term experiments. Net photosynthesis increased significantly with increasing CO2 concentration at all light intensities, even at the lowest one. The optimal temperature for photosynthesis increased with CO2 enrichment. The changes in photosynthesis when the CO2O2 ratio was varied suggest that the effect of CO2 enrichment is a result of a reduction in photorespiration.To determine whether the increase in photosynthesis caused by CO2 enrichment would produce a greater yield, tomato plants were cultivated from seed to harvest in a tightly-closed greenhouse that was enriched with CO2 continuously during the entire growing-period. The control greenhouse was ventilated by openings in the roof and door. The temperature of the 2 greenhouses was kept the same. Plants enriched with CO2 showed a significant increase in fresh and dry weight and yield of tomatoes. The results are discussed in relation to earlier work in which CO2 enrichment was discontinued when there was a need for ventilation.  相似文献   

16.
The effects of ethephon or GA3 on sex expression of Chinese chestnut (Castanea mollissima BL.) were opposite to the effects of these plant growth regulators on cucumber, pumpkin and Chinese white-flowered gourd. Ethephon at 100–500 mg 1?1 inhibited the development of female flowers and promoted that of male flowers. GA3 at 50–500 mg 1?1 caused a significantly lower number of male inflorescences, but increased the number of female flowers. Urea applications decreased the number of male inflorescences and increased the number of female flowers. For plants grown on phosphorous-deficient soils, fertilizing with superphosphate also increased the number of female flowers. Spraying trees with GA3, urea or a mixture of both increased the number of female flowers. Therefore, it is proposed that such applications should be employed at the onset of differentiation of flower primordia of Chinese chestnut to increase the ratio of female to male flowers.  相似文献   

17.
Soaking of bulbs in 3 concentrations of indoleacetic acid (IAA), gibberellic acid (GA3), 2-chloroethyltrimethyl ammonium chloride (cycocel) or 2-chloroethylphosphonic acid (ethrel) showed various responses on growth and flowering. IAA increased the weight and number of bulblets, GA3 increased bulb weight. Cycocel (1000 mg l?1) increased the number of flowers, while GA3 increased the diameter of the flowers.Application of IAA at 100 mg l?1 and GA3 at 10, 100 or 1000 mg l?1 twice as foliar spray at an interval of 30 days promoted the number of bulblets on the treated plants, while high concentrations of cycocel and ethrel (1000 mg l?1) increased the weight of bulblets. All concentrations of IAA, GA3 and 1000 mg l?1 cycocel increased the number and size of the flowers.  相似文献   

18.
Brunonia australis R. Br (Goodeniaceae) and Calandrinia (Portulacaceae), native to Australia, are potential new flowering potted plants. This research investigated the role of daylength and growth regulators, Gibberellic acid (GA3) and paclobutrazol (Pac), to control vegetative growth, peduncle elongation and flowering of Brunonia and Calandrinia. Plants were grown under long days (16 h), short days (11 h) and 8 weeks under short day then transferred to long day (SDLDs). Plants in each daylength were treated with GA3, Pac, and GA3+ Pac. GA3 was applied as 10 μL drop of 500 mg L−1 concentration to the newest mature leaf. A single application of Pac was applied as a soil drench at 0.25 mg a.i. dose per plant. Both Brunonia and Calandrinia flowered earlier in long days but still flowered in short days, so both can be classified as facultative LD plants. Brunonia under SDLDs were more vigorous and attractive than plants under LDs while still being more compact than plants under SDs. In Brunonia, GA3 promoted earlier flowering and increased the number of inflorescences under SDs. Pac at 0.25 mg a.i. per plant applied alone or in combination with GA3 had extended flower development in Brunonia, and resulted in a reduced number of inflorescences per plant compared to the control plants. Vegetative growth of Calandrinia was similar under LDs, SDs and SDLDs, whereas GA3 application increased plant size. Pac-treated Calandrinia looked compact and attractive, and Pac application did not affect time to flower and flower number.  相似文献   

19.
Preliminary studies showed that a Bacillus subtilis strain stimulates plant growth. We investigated how inoculating seeds of a sunflower cultivar (Helianthus annuus L.) with this strain stimulated plant growth, soil properties and emissions of greenhouse gasses, i.e. carbon dioxide (CO2) and nitrous oxide (N2O), when cultivated in a greenhouse. Unfertilized sunflowers or fertilized with urea served as controls. After one month, root length and fresh and dry root weight of the sunflower was significantly higher in the bacteria amended plant than in the urea and unfertilized plants. However, at harvest, no positive effect was observed. The number of seeds per plant and seed weight was not significantly different between the treatments, but total plant N was significantly higher in urea-amended plants than in unfertilized plants. The CO2 production rate was not affected by treatment, but the N2O emission rate was significantly higher in soil amended with urea plus bacteria soil compared to the unfertilized treatments. It was found that the B. subtilis strain used in this study had a positive, but only temporarily effect on growth of the sunflower cultivar used.  相似文献   

20.
Field grown day-neutral, June-bearing and everbearing strawberry cultivars responded similarly to GA3 in most cases. GA3 stimulated daughter-plant production in ‘Hecker’ (DN) and suppressed it in ‘Guardian’ (June). Fifty mg l?1 GA3 increased initial runner production of all cultivars, while both 50 and 100 mg l?1 GA3 increased fruit yield the year following treatment. In greenhouse studies, GA3 initially increased leaf number, petiole length and runner production, but the effects diminished with time. Phthalimide at 1000 mg l?1 was most effective in increasing leaf number.  相似文献   

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