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1.
Application of 2,4-D and 2,4,5-T at concentrations ranging from 5 to 20 mg l?1 to 5-year-old ‘Pant Lemon-1’ (Citrus limon Burm) trees reduced the vegetative growth in terms of height, spread, shoot length, number and size of the leaves in the autumn flush. Various NAA treatments (5–20 mg l?1), however, enhanced growth, but not to the extent that was observed after GA3 treatments. Application of GA3 at 10–40 mg l?1 significantly enhanced all aspects of growth, and the effects were most pronounced at 20 and 40 mg l?1. Nutritional status of the leaves showed a slight variation in relation to vegetative growth under various treatments.Some 2,4-D- and 2,4,5-T-treatments increased the fruit yield over the control, which could suggest mobilization of foods even at the expense of reduced vegetative growth. On the other hand, NAA, particularly at 10 mg l?1, increased both vegetative growth and yield, suggesting that the transport of the photosynthates from the leaves to the fruits was not at the expense of new growth extension. Due to excessive growth enhancement under higher concentrations of GA3 (20 and 40 mg l?1), comparatively fewer nutrients were translocated to the fruit “sinks”, thereby resulting in a non-significant decrease in yield. 相似文献
2.
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
3.
A study on the effect of maleic hydrazide (MH) on vegetative growth, flowering and yield of bottle gourd (Lagenaria siceraria (Mol) Standl.) was conducted during the rainy and summer seasons of 1979 and 1980, respectively. MH at 150 mg l?1 stimulated the elongation of the main shoot, while MH at 50 mg l?1 induced more branches per plant. Staminate flowers appeared late and at the lowest node number in control plants, whereas MH at 150 mg l?1 had a profound effect on the earliest appearance of pistillate flowers at the lowest node number. Male: female ratio was lowered with MH at 50 mg l?1 and was most effective in producing the maximum number of fruits and fruit weight per plant and ultimately the yield. GA3, NAA and ethrel did not influence yield, while MH did. 相似文献
4.
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
5.
Investigations were undertaken to explore the possibility of improving setting, retention and weight of fruits in ‘Early Seedless’ and ‘Calcuttia’ cultivars of lichi (Litchi chinensis) by means of growth regulators. Indole acetic acid (IAA) at 20, 40 and 80 mg l?1, 2,4-dichlorophenoxy acetic acid (2,4-D) at 2,4 and 8 mg l?1 and gibberellic acid (GA3) at 50, 100 and 150 mg l?1 were sprayed on panicles in the first fortnight of April, when 50–100% flowers had opened. All 3 growth regulators caused a favourable effect on fruit setting, fruit retention and weight of individual fruits, but IAA at 20 mg l?1 proved the best for enhancing setting, GA3 at 50 mg l?1 for increasing retention and GA3 at 100 mg l?1 for improving fruit weight. IAA and GA3 should, therefore, be used in combination. Between the 2 cultivars tested, ‘Calcuttia’ proved superior to ‘Early Seedless’ in fruit setting, fruit retention and weight of individual fruits. 相似文献
6.
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
7.
Qualities of Indian gooseberry fruits (Phyllanthus emblica L.) were determined after dip-treatment with wax emulsion (WE) with or without morphactin (Mor) and gibberellic acid (GA3). Dip-treatments with 100–500 mg l?1 Mor reduced marketability by inducing browning and high weight loss, but loss in ascorbic acid was checked and phenols increased. 10 mg l?1 Mor maintained marketability at par with control, effectively controlled loss in ascorbic acid, and increased acidity and reducing sugars. GA3, although failing to control the loss of ascorbic acid, was effective in checking browning and thereby increased the market value of fruits as compared with controls and Mor-treated fruits.WE with or without Mor (10 mg l?1) controlled browning, accumulation of phenols and losses in weight and moisture as compared with 10 mg l?1 Mor, 100 mg l?1 GA3, or control, but could not retain ascorbic acid in comparison to 10 mg l?1 Mor-treated fruits. Marketability of fruits having had treatment with either WE or GA3 was the same. Fruits having had combined treatment with WE and 10 mg l?1 Mor had maximum marketability. Minimum marketability was observed in fruits subjected to a combined treatment of WE + 100 mg l?1 GA3 due to maximum infection with Aspergillus spp. and Penicillium spp. 相似文献
8.
Worldwide, gibberellic acid (GA3) is used routinely to increase fruit number and size of seedless mandarins. The efficacy of seven combinations of GA3 concentrations and application times to maximize total yield and yield of commercially valuable fruit (diameter 57.2–76.2 mm) of ‘Nules’ Clementine mandarin (Citrus reticulata Blanco) was determined in a commercial orchard. GA3 applied during the period of intense flower abscission failed to reduce the total number of abscised flowers in both the light off- and heavy on-bloom years. No GA3 treatment reduced fruit abscission when trees were setting the low yield off-crop. However, all trees receiving GA3 in the high yield on-crop year had fewer abscised fruit than untreated control trees (P = 0.0188) and GA3 applied 10 days after 75% petal fall and in July increased the number of fruit retained on tagged branches >20% compared to control trees (P = 0.0005). Maximum air temperature was not related to flower or fruit abscission. In the off-crop year (548 fruit per untreated control tree), it was necessary to apply 15 or 25 mg L−1 GA3 at 60% bloom, 90% bloom, 75% petal fall and 10 days after 75% petal fall to significantly increase the number of fruit per tree and yield of commercially valuable fruit (kilograms and number per tree) (P < 0.0001) above that of control trees, with no reduction in total kilograms per tree. In the following on-crop year, it was better not to apply GA3: no treatment increased total yield or fruit size and five of seven GA3 treatments tested reduced total yield as kilograms and number of fruit per tree (P = 0.0003). The results provide strong evidence that GA3 efficacy is crop load-dependent and dictate that crop load should be considered when using GA3 to increase fruit set or fruit size of mandarins. 相似文献
9.
Zhiguo Ju Yousheng Duan Zhiqiang Ju 《The Journal of Horticultural Science and Biotechnology》2013,88(5):579-583
SummaryDifferent concentrations of aminoethoxyvinylglycine (AVG) and gibberellic acid (GA3) and their combinations, applied at two stages of fruit growth, were evaluated for prolonging the marketing season of `Feicheng' peaches. GA3 applied at the end of pit hardening, or AVG applied two weeks before commercial harvest, inhibited fruit maturation on the tree, delayed harvest and reduced flesh browning after cold storage in a concentration-dependent manner. A synergistic effect was found when both GA3 and AVG were used, with the combination of 100 or 150.mg l±1 GA3, applied at the end of pit hardening, and 100 mg l±1 AVG, applied two weeks before harvest giving the best results. These combinations retarded the change in ground colour, loss of firmness, and reduction in acidity by 2±3 weeks. Since harvest was prolonged by 2±3 weeks, soluble solids content (SSC) in fruit increased compared with the control (harvested earlier). Fruit size was significantly greater on treated trees compared with the controls when fruit set was controlled to the same level by hand thinning. After four weeks of storage and 4.d at 208C, 83% of control fruit developed tissue browning, but only 5% of AVG + GA3-treated fruit developed browning after six weeks of storage and 4 d at 208C. Thus, the marketing season of `Feicheng' peaches was prolonged by at least four weeks by 100 or 150 mg l±1 of GA3 and 100 mg l±1 of AVG. Fruit treated with 150 mg l±1 GA3 plus 100 to 150 mg l±1 AVG showed similar results but failed to ripen properly after cold storage. 相似文献
10.
Despite problems of low fruit set, small fruit size and alternate bearing, the Hass cultivar dominates commercial avocado production worldwide. To increase yield and fruit size, gibberellic acid (GA3) (25 mg L−1) was applied at different stages of ‘Hass’ avocado tree phenology: (i) mid–late April (flower abscission), end of June–beginning of July (fruit abscission and beginning of the exponential phase of fruit growth), and mid-January (beginning of pre-harvest fruit drop); (ii) end of June–beginning of July; and (iii) mid-September (near the end of the major fruit abscission period; period of exponential fruit growth). In both years of the research, applications of GA3 in April and June–July were within the periods of intense flower and fruit abscission, respectively; fruit abscission was low in September and January. Maximum air temperature was not related to flower or fruit abscission. In the on-crop year (391 fruit per untreated control tree), a single application of GA3 at the end of June–beginning of July significantly increased total yield (kilograms only) and yield of commercially valuable fruit (178–325 g/fruit) (as kilograms and number per tree) compared with the control (P < 0.0001). GA3 applied in September increased total yield (kilograms only) and yield of commercially valuable fruit (kilograms and number per tree) to values intermediate to and not significantly different from all other treatments, except trees receiving multiple applications of GA3. This treatment reduced total yield and yield of commercially valuable fruit (kilograms and number per tree) relative to all treatments (P ≤ 0.0002). In contrast, during the off-crop year (32 fruit per control tree), no GA3 treatment had a significant effect on yield or fruit size compared with the control and all other GA3 treatments. For ‘Hass’ avocado, there was no negative effect from applying GA3 at the end of June–beginning of July in both the off- and on-crop years; 2-year cumulative total yield and yield of commercially valuable fruit were increased by 27 kg (128 fruit) and 22 kg (101 fruit) per tree, respectively, above the yield of untreated control trees (P < 0.0001). 相似文献
11.
《International Journal of Fruit Science》2013,13(3):33-40
ABSTRACT Gibberellic acid (GA3) at 25, 50, and 100 mg-L?1 and naphthalene acetic acid (NAA) at 20, 40, and 80 mg-L?1 were sprayed to runoff on flower panicles of 15-year-old lychee trees one week after panicle emergence. Trees sprayed with water only were used as the control. The number of male flowers was increased quadratically by NAA compared to the control in 2000, and 2001. The number of hermaphrodite flowers functioning as female (HF-F) and the number of hermaphrodite flowers functioning as male (HF-M) was reduced quadratically by all concentrations of NAA both years. The greater the NAA concentration, the greater the reduction. The total number of flowers was also reduced by all NAA concentrations both years. Fruit set (percentage of total HF-F flowers) was reduced quadratically by NAA in 2001, but had no effect in 2000. The number of male flowers was increased quadratically by GA3 both years. Regression analysis also showed a positive relationship between GA3 and HF-F flowers both years. However, hermaphrodite flowers functioning as male (HF-M) was reduced quadratically by GA3 both years. In addition, the total number of flowers and fruit set was increased quadratically by GA3 both years. GA3promotion of male flowers, HF-F production, and increased fruit set may have important bearing on yield improvement. 相似文献
12.
The application of gibberellic acid during flower bud induction significantly reduced flowering of ‘Black Diamond’ and ‘Black Gold’ Japanese plums. The response depended on the concentration applied and on the type of shoot. Mixed shoots had a similar response in both varieties, flowering being reduced by 40% for GA3 50 mg l−1 and by 75–90% for GA3 75 mg l−1 or higher concentration. With regard to spurs, GA3 50 mg l−1 reduced flowering intensity by 40% and 25% in ‘Black Gold’ and ‘Black Diamond’, respectively, and GA3 75 mg l−1 or higher concentration reduced flowering by 70% and 50%, respectively. This partial inhibition of flowering significantly reduced the cost of manual thinning. The best GA3 concentration was found to be 50 mg l−1, since it reduced the cost of thinning by 45–47% and increased final fruit weight by 7–33% for ‘Black Diamond’ and ‘Black Gold’, respectively. Not significant differences in yield and in mature fruit characteristics of treated trees were found compared to untreated trees. 相似文献
13.
Final fruit diameter is the prime determinant of sweet cherry fruit value. Previous research has shown that mesocarp cell size accounts predominantly for variability in final fruit size, within a genotype. Our research program evaluated the potential to improve sweet cherry fruit size/weight with growth regulators to affect cell division and/or cell expansion stages. In the current study we screened 8 plant growth regulators (PGRs), including cytokinins, gibberellins, and auxins, and their combinations for their ability to increase ‘Bing’ fruit weight. Each PGR was mixed in lanolin paste and applied to fruit pedicels at 9 or 30 days after full bloom (DAFB), to coincide with estimated peak in cell division and cell expansion activity, respectively. Several cytokinins applied 30 DAFB improved fruit weight significantly (ca. +15%) with N-(2-Chloro-4-pyridyl)-N′-phenylurea (CPPU) and 6-(3-hydroxybenzylamino) purine (mt-Topolin) at 100 mg l−1 being the most effective. Gibberellins, applied alone, improved fruit size and delayed fruit maturation and exocarp coloration. GA3 at 200 mg l−1 applied at 9 DAFB was the most effective and improved final fruit weight by 15%. Fifty-six percent of the fruit from this treatment were ≥9 g compared to 15% of similar weight fruit from untreated limbs. Both GA3 and GA4/7 treatments applied 9 DAFB increased fruit radial expansion. 4-Chlorophenoxyacetic acid, a synthetic auxin, also stimulated higher fruit growth rates at stage I and stage II, and fruit color development, but did not improve final fruit size. 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.
This study evaluates the effect of gibberellic acid (GA3) in inducing parthenocarpy in ‘Algerie’ loquat, as well as the optimum treatment conditions and associated techniques, hand thinning and ringing, to produce seedless fruit with high enough quality for fresh consumption. GA3 applied in the course of the phenological growth stages 504–508 of the BBCH-scale produced seedless fruits, with the magnitude of the response depending on the concentration applied and number of treatments. Percentage of panicles bearing seedless fruitlets significantly increased with increasing GA3 concentrations up to 100 mg l−1 and significantly and positively correlated with the number of treatments applied. Trees treated three times with 100 mg l−1 developed more than 90% of panicles bearing almost 7 seedless fruits per panicle, which were smaller in size, drier and slightly acid but similar in TSS concentration and skin colour than seeded fruits from untreated trees. Fruit thinning to 3 fruits per panicle did not increase seedless fruit size, but ringing performed at the onset of cell enlargement stage, growth stage 702 of the BBCH-scale, significantly increased fruit size by 12–15%, depending on the year. Trees treated three times with 100 mg l−1 of GA3 and ringed produced 26 kg, on average, of seeded fruit of suitable commercial quality. 相似文献
16.
Sprays with 250–2000 mg l?1 propyl 3-t-butylphenoxy acetate (MB 25,105) and 250 and 500 mg l?1 GA4+7 + 6-benzyladenine (Promalin) were applied to scion growth of first nursery trees of ‘Bartlett’ pear (Pyrus communis L.), ‘Bing’ cherry (Prunus avium L.) and ‘Oregon Spur II Delicious’ apple (Malus domestica Borkh.) to stimulate lateral branching in the nursery. Most treatments significantly increased branching compared to untreated controls. Combination sprays of the two chemicals were usually better than either used alone. Chemical treatment usually produced greater branching and wider branch angles than mechanical heading. Both chemical and mechanical treatments reduced tree height and caliper, but the decrease was not always statistically significant. 相似文献
17.
‘St. Julien A’ (Prunus instititia L.) rootstock was induced to proliferate shoots on a modified half-strength Murashige and Skoog (MS) medium. Cultures treated with 12.5 mg l?1 gibberellic acid (GA3) produced elongated shoots suitable for rooting. Elongated shoots were placed in media with indolebutyric acid (IBA) or indole-3-acetic acid (IAA) with or without a 16-day dark incubation. Light (16-h photoperiod) inhibited rooting. IAA (4 mg l?1) was ineffective in promoting rooting. Rooting was best when shoots were incubated in the dark with IBA (4 mg l?1). GA3 was deleterious to shoots, causing chlorosis and apical die-back. Light regime interacted with auxin treatments in affecting shoot condition. Shoot condition was better on shoots treated with IBA and dark-incubated; while those treated with IAA were better when light-incubated. 相似文献
18.
Carmina Reig Vittorio Farina Giorgio Volpe Carlos Mesejo Amparo Martínez-Fuentes Francesca Barone Francesco Calabrese Manuel Agustí 《Scientia Horticulturae》2011
The application of gibberellic acid (GA3) to the whole loquat tree from mid-May to early June and from early August to the onset of flowering, significantly reduced the number of premature flowering shoots per current shoot and per m3 of canopy, and so reduced the total number of panicles per m3 of canopy. The number of vegetative shoots per m3 of canopy was also significantly reduced by applying GA3. The response depended on the concentration applied and produced optimal results at 50 mg l−1. Differences in the number of flowers per panicle and leaves per shoot were not significantly modified by the treatment. Nevertheless, GA3 applied directly to the developing apex near to flower differentiation reduced the number of flowers per panicle by 25–35% and without modifying the morphological characteristics of the panicle. Results suggest that less sprouting of lateral buds was largely responsible for the reduction in flowering intensity caused by GA3. Best treatments reduced thinning costs (60%, approximately) of premature flowering shoots, slightly increased fruit diameter and significantly improved fruit colour and juice quality, thus advancing harvest date. 相似文献
19.
《Scientia Horticulturae》1986,28(4):323-329
Sambucus caerulea (elder) seeds did not germinate after 4°C cool treatments for up to 30 days, when monitored for a further 30 days at 21°C. When seeds were soaked for 24 h in gibberellic acid (GA3) prior to and during cold treatment, germination percentage depended on GA3 concentration and duration of cold treatment. The highest germination percentage was 55 (1000 mg l−1 GA3 for 30 days at 4°C). When seeds were treated with ethephon at 0, 100 or 1000 mg l−1, no germination was recorded after a subsequent 30-day 4°C treatment. Ethephon added to GA3 gave a strong interaction, leading to further promotion in germination. Optimal germination was obtained after 1000 mg l−1 GA3 and 100 mg l−1 ethephon for 30 days at 4°C (69%).The addition of ethanol, acetone, dimethyl sulfoxide or polyethylene glycol to the GA3 soak as infusion agents either reduced or did not change the germination percentage. 相似文献
20.
Experiments were conducted to observe the effects of foliar application of gibberellic acid on vegetative growth, flowering, fruiting and various disorders in ‘Chandler’ strawberry. GA3 (75 ppm) was applied to the strawberry plants either during mid-November (at fruit bud differentiation stage), or mid-February (pre-flowering stage) or at both times. Fruit under control were sprayed with tap water only. Observations were recorded on vegetative attributes like crown height, crown spread, petiole length, leaf number, leaf area; flowering and fruit set, fruit size; production of albino, malformed and button berries, total yield and marketable fruit yield and quality parameters, like juice content, TSS, ascorbic acid contents, acidity etc. Results indicated that GA3 (75 ppm) spray either during mid-November or mid-February or at both times has favourably influenced all vegetative attributes of ‘Chandler’ strawberry over control. Similarly, fruit set was increased, and production of malformed and button berries was reduced, but albinism remained unaffected. Although individual berry weight was reduced slightly, but fruit number, total as well as marketable yield was increased tremendously over control with no adverse effect on fruit quality parameters. In all, spraying GA3 both during mid-November and mid-February was much more effective in achieving the desirable results than single application of GA3 either during mid-November or mid-February. 相似文献