首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
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   

2.
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   

3.
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   

4.
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   

5.
Summary

The effects of a post-harvest application of gibberellic acid (GA3) at various concentrations (0, 10, 25, 50, or 100 mg l–1) and for different periods of incubation (1, 2, or 3 h) on the breaking of dormancy and on sprouting in potato (Solanum tuberosum L., cv. Marfona) minitubers of two ages (freshly-harvested or 1 week after harvest) were investigated. Compared with untreated, control minitubers, GA3-treated minitubers showed a significantly shorter period of dormancy (46 d), especially when the minitubers were treated at all concentrations immediately after harvest (41 d). GA3 treatment had a greater effect on dormancy in freshly-harvested minitubers than in 1 week-old minitubers, probably because of the reduced uptake of GA3 solution after skin-set. At lower concentrations of GA3, the period of dormancy tended to decrease the longer the minitubers were immersed in the GA3 solution. In contrast, at higher concentrations of GA3, the duration of immersion only had an effect up to 2 h and any longer immersion was ineffective. The average number of sprouts was not affected by GA3 concentration, or by the time of incubation, but was significantly higher for freshly-harvested minitubers (1.4) than for 1 week-old minitubers (1.2). The lengths of the sprouts increased with an increase in GA3 concentration, especially in freshly-harvested minitubers. Consequently, immersing freshly-harvested potato minitubers in a low concentration of GA3 (up to 25 mg l–1) for up to 3 h effectively shortened the period of dormancy and led to the formation of sprouts of optimum length.  相似文献   

6.
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   

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.
‘Alaska’ and ‘Redwing’ azaleas having dormant flower buds were sprayed with gibberellins (GA3 or GA4 + 7) alone and in combination with thiourea, N6 benzyl adenine (BA) or kinetin weekly for 3 or 4 weeks to test the efficacy of these materials in breaking bud dormancy. Additional plants received 6 weeks of cold storage at 4.5°C or glasshouse day temperatures of 21°C and above. The 2000 and 3000 mg l?1 GA3 and Ga4 + 7 sprays were better than 1000 mg l?1 in promoting flowering, with ‘Redwing’ responding better than ‘Alaska’. GA-treated plants flowered in fewer days than those receiving cold storage. Flower diameter and pedicel length increased with higher levels of GA, and flower uniformity was comparable to cold-stored plants on most GA-treated ‘Redwing’-plants. Thiourea, BA and kinetin applied alone had no effect and considerable cytokinin activity was highest in GA-treated buds 14–21 days after treatment application. No increase in activity occurred on plants not receiving GA.  相似文献   

9.
Gibberellic acid (GA3) treatment of forced tulip crops has potential for producing faster growth to anthesis in the glasshouse, for reducing losses due to floral bud blasting, and for reducing the duration of cold storage needed to obtain satisfactory flowers. Using partly and fully cooled direct-forced tulips, cultivar ‘Apeldoorn’, several factors (relevant to the definition of GA3 treatments) were studied. Experiments confirmed the previously recorded effects of gibberellins in tulips: GA3 injections reduced the duration of the glasshouse period, enhanced flower survival and flower length, and reduced stem length at flowering.Following bulb storage at temperatures from ?2 to 20°C, GA3 reduced the glasshouse period by 15–25% and increased flower length, compared to controls, irrespective of storage temperature. Stem length was also reduced by GA3, this effect being greater following a storage temperature of 5°C or lower. When GA3 was applied during the period of 17°C-storage which precedes cool storage, or during or after storage at 5°C, it was found that treatments during or at the end of cool storage were more effective in producing the characteristic effects of GA3 than were pre-cooling applications. In partly cooled bulbs (but not fully cooled ones), the GA3-induced earliness of flowering was about doubled when GA3 injections were given repeatedly at 2-week intervals throughout storage. The responses to GA3 injections were found to be unmodified by early-lifting and heat-treatment (for earlier forcing), by delaying the start of 5°C storage (for later forcing), by glasshouse temperature (16 and 18°C), and by shading treatments; there was little effect of bulb size.  相似文献   

10.
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   

11.
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   

12.
‘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   

13.
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   

14.
《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   

15.
A single GA3-spray at petal-fall to the entire tree enhanced initial set in the ‘Navelate’ sweet orange (Citrus sinensis L. Osbeck), but this effect was transient and in most cases final yield was not increased. When followed by girdling, final yield was increased even in the most productive orchards, this effect being due to an increase in fruit number while fruit size was unaffected. The response was markedly dependent on the GA3 concentration, 5 mg l?1 giving the best results. Higher concentrations up to 20 mg l?1 even reduced yield compared to the untreated control trees. Chlormequat reduced the number of fruits finally cropped without affecting their size, an effect which may be explained through a reduction in the endogenous gibberellin levels.  相似文献   

16.
Radicle emergence in lettuce seeds cultivar ‘Hilde’ was reduced by NH4NO3 above 8×10?2M, while radicle extension was inhibited by 8×10?2M NH4NO3 and no seedlings emerged. Inhibition of radicle emergence by 8 and 16×10?2M NH4NO3 was prevented by soaking seeds for 4 h before sowing in a mixture of GA47 and kinetin+phosphate buffer, and was partially prevented by soaking them for 4 h before sowing in phosphate buffer. These treatments did not prevent inhibition of radicle emergence by 32×10?2M NH4NO3, but seeds soaked in growth regulators or phosphate buffer before sowing and taken from this NH4NO3 solution after 7 days and washed to remove excess salt gave 45–52% germination compared with 12 % for untreated seeds. Pre-treatment of the seeds did not prevent the inhibitory effect of NH4NO3 on radicle extension. In field experiments seeds treated with growth regulators + phosphate buffer or phosphate buffer alone gave a higher final percentage emergence from soils given 125 kg N/ha than did untreated seeds.  相似文献   

17.
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   

18.
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   

19.
Summary

Seeds of an andromonoecious muskmelon, cv. Piel de Sapo, were sown between the 5th and the 10th days of each month of 1986 and plants were kept in a glasshouse in Zaragoza (Spain). Plants were treated with 0, 150, 250 and 500 mgl?1 ethephon solutions at three stages of development: two leaves, anthesis of the first male flower and anthesis of the first pistillate flower respectively. Plants sown in January, February, March and April achieved higher feminization rates than plants sown in May, June and July. Plants sown in September, October and November did not produce any pistillate flowers. When the plants were sown in December, the feminization rate was intermediate. When control plants had high feminization rates, treatments with 150 mg l?1 ethephon solutions produced maximum feminization, while when these plants had low feminization rates, higher ethephon concentrations (250 or 500 mg l?) were needed.  相似文献   

20.
Summary

The potency of paclobutrazol, BAS 111, triadimefon and triapenthenol in promoting adventitious root formation and their interactions with gibberellic acid (GA3) were studied by using the mung bean (Vigna radiata (L.) R. Wilcz) rooting bioassay. Isoactive concentrations of the four compounds required for the formation of an average of 50 roots per cutting were 0.09, 0.8, 1.5 and 9 mg l–1, respectively. GA3 applied in combination with each retardant reversed its promoting effect. For the reduction of the number of roots (ca. 50) of cuttings treated with isoactive concentrations of the retardants to that of the untreated control (9–10 roots) the required concentration of GA3 for triadimefon and triapenthenol was twice as high as for paclobutrazol and BAS 111. At high concentrations of GA3 the difference between the number of roots in treatments, with and without paclobutrazol, was fully eliminated, but not when triapenthenol replaced paclobutrazol. Application of paclobutrazol, triadimefon or GA3 to cuttings for 24 h intervals over the first five days of the assay, showed significant changes in their effectiveness, which followed a similar pattern for the three substances. Rooting was increased by the retardants without reduction of the cutting length. The results suggest that the retardants promote rooting by interfering with gibberellin biosynthesis but, in addition, some act by influencing another process or processes.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号