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1.
GA4+7 concentrations, treatment date, number and frequency of treatments were factorially combined to determine their effects in preventing russeting of ‘Golden Delicious’ apples.The greatest reduction of russet was obtained by treating fruitlets 8 or 15 days after full bloom.Optimum timing and number of treatments provided better control of russet than high concentrations of gibberellins, although in some cases, higher doses improved russet control.Length of pedicel and ratio of longitudinal to transversal diameter were greater where russeting was reduced, and significant correlations were observed between fruit and pedicel length, and russeting. GA4+7 treatments also affected setting, and in many cases caused parthenocarpy.  相似文献   

2.
《Scientia Horticulturae》2005,104(3):265-273
In Japan, artificial pollination is practiced to improve fruit set as well as fruit size and to obtain perfect round shapes in ‘Housui’ (S3S5) Japanese pear and most commercial cultivars that present gametophytic self-incompatibility. The period of artificial pollination application is limited by environmental conditions and the availability of a labor force. The present study aimed to determine if pre-pollination applications of putrescine (1.0 and 0.01 mM) positively affect fruit set in ‘Housui’ after hand-pollination. During 2002 and 2003, fruit set in late pollinated flowers increased with pre-pollination putrescine applications and concentrations of 1.0 mM had a better effect than 0.01 mM. In vitro pollination tests revealed that higher pollen germination was present in the stigmas of flowers sprayed with 1.0 mM of putrescine compared to the controls. Putrescine application did not affect post-pollination ethylene production in the styles. Moreover, in the styles of non-treated flowers, an increment of putrescine content and ethylene production after pollination was found, suggesting post-pollination responses and confirming the lack of antagonism between polyamines and ethylene at least during this process.  相似文献   

3.
Fruit set was increased by removing all shoots 5 days after full bloom and at weekly intervals thereafter from trees of Sunset and Laxton’s Fortune, but removing shoots from Fortune trees 25 days after full bloom produced no beneficial effect on fruit retention. All treatments resulted in a heavier rate of fruit shedding during the ‘June drop’ period than occurred from control trees, and at harvest the trees without shoots had fewer fruits, and lower yields, than the controls. In a comparison of shoot removal and shoot tip removal starting 15 days after full bloom on Fortune trees, both treatments improved set, but whereas shoot removal caused a heavier ‘June drop’ compared with untreated trees, shoot tip removal increased the number of fruits retained to harvest and produced a yield increase. The difference between the two treatments in their influence on fruit retention, during and after the ‘June drop’, is accounted for by the beneficial effect of a relatively small number of leaves on each tipped shoot. Studies on the pattern of distribution of photosynthates, using 14CO2 and autoradiography, produced results supporting the concept of competition between fruits and shoots and also showed changes in the pattern of assimilate movement brought about by shoot tip removal. It is concluded that competition between fruits and shoots, occurring during blossoming and the following 2–3 weeks, may limit fruit set, but the presence of shoot leaves is beneficial to fruit retention in the later part of the season, particularly during the ‘June drop’ period.  相似文献   

4.
The influence of soil drench applications of ancymidol (0.5 mg), GA3 (25 mg), and Ga4+7 (25 mg) was determined on the growth and development of the tulip under greenhouse conditions. Ancymidol applied on greenhouse day 1 or 6 significantly reduced the total length of the scape. Maximum reduction in growth occurred in the first internode, with a declining effect on internodes 2, 3 and 4. GA4+7 applied simultaneously with ancymidol completely reversed the ancymidol effects. GA3 was relatively ineffective. Compared to control plants, ancymidol reduced the number of cell divisions in the first internode, but not in the fourth internode. Cells of ancymidol treated plants were reduced in length and exhibited greater radial expansion. Ancymidol reduced the fresh weight of the stem and tended to conserve the fresh weight of the mother scales. The effect on the leaves and roots was variable. Ancymidol tended to increase the fresh weight of the daughter bulblets. There was no significant effect of ancymidol or the GA's on floral morphology or the number of days to flower in the greenhouse.  相似文献   

5.
The effects of hand-pollination and spraying with N-(2-chloro-4-pyridyl)-N′-phenylurea (CPPU) on fruit set and fruit growth of ‘Matsumoto-Wase-Fuyu’, which is a member of the pollination-constant, non-astringent group of persimmons (PCNA) were investigated. Staminate flowers of pollinizers in the orchard were eliminated before anthesis. Hand-pollination was carried out at full bloom (FB). Without prior hand-pollination, CPPU at 5 or 10 mg 1−1 was sprayed 11 days after FB. Hand-pollination and spraying with CPPU increased fruit set before thinning of fruits by hand. The number of fruits after thinning did not differ among treatments. The yield of marketable fruits after hand-pollination was similar to that after treatment at 5 mg 1−1, but was higher than that for untreated trees. Formation of a sunken fruit apex, which was observed in about 30% of fruits from untreated trees, was suppressed by application of CPPU. CPPU also delayed coloration of fruit. There were no differences among treatments in firmness or soluble solids concentrations of marketable fruits.  相似文献   

6.
The relationship between 9,10-ketol-octadecadienoic acid (KODA), GAs and jasmonic acid (JA) and flower bud formation influenced by fruit load in apples (Malus domestica Borkh.) was investigated. The endogenous KODA and JA concentrations in apical buds in plants subjected to flower thinning treatment (FTT), under which all flowers were removed were higher than those in plants subjected to heavy crop treatment (HCT), under which the number of leaves per fruit was adjusted to 20 from 60 to 120 days after full bloom (DAFB). In contrast, the gibberellic acid concentrations [total of gibberellin A1 (GA1) and gibberellin A4 (GA4)] in FTT plants were low compared with those in HCT plants. The result suggests that KODA and JA in contrast to GAs may have opposite effects on flower bud formation which is significantly influenced by fruit load in apples and that KODA and JA may also be associated with flower bud formation in apples.  相似文献   

7.
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   

8.
Foliar applications of gibberellins (GA3, GA4,7) and 6-benzylamino-9-(2-tetra- hydropyranyl)-9H-purine (PBA) were compared with untreated controls and the conventional low temperature treatment for breaking flower bud dormancy. GA3 and GA4, 7 were compared for their role in promoting flower development. Treatments were initiated when microscopic examination showed the flower buds had reached Stage 6 (style elongated and closed). Plants that did not receive a dormancy-breaking treatment failed to reach anthesis. Application of GA3 or GA4, 7 hastened flowering and increased flower size and pedicel length.  相似文献   

9.
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   

10.
The present study was carried out to improve fruit set, yield, quality, marketability, and exportability of ‘Washington’ Navel orange. Pre-harvest foliar sprays of GA3, K, and Ca, either alone or combined, were applied at full bloom. The following treatments were applied: {control (T1), 25 mg/L GA3 (T2), 2% K2SO4 (T3), 25 mg/L GA3 + 2% K2SO4 (T4), 25 mg/L GA3 + 2% Ca Cl2 (T5), 2% K2SO4 + 2% Ca Cl2 (T6), and 25 mg/L GA3 + 2% K2SO4 + 2% Ca Cl2 (T7). All treatments improved fruit set, yield, physical and chemical characteristics, mineral content of leaves and fruit rind, and the percentage of exportable fruit in comparison to the control. Fruit set, fruit detachment force, peel firmness, and the mineral content of leaves and fruit rind were enhanced significantly with the combination of GA3 + K2SO4 + Ca Cl2 (T7) in comparison to all other treatments and the control. Results indicated that all foliar combination treatments improved fruit quality and marketability, and increased the percentage of exportable fruit and reduced the defects of non-exportable fruit.  相似文献   

11.
The application of GA3 alone or in combination with auxins and/or diphenylurea delayed the development of red colour on cherries if applied at the cot-split stage or two weeks after full bloom. Petal-fall applications were less effective and blossom-time applications ineffective in this respect. The hormone mixtures did not induce a significantly different response from GA3 alone. Application of daminozide enhanced red colour development, totally counteracting the effect of GA3 applied at petal-fall and partially that of GA3 applied later .The soluble solids content of the fruits was reduced by the hormones and increased by daminozide. Fruits were smaller where hormone treatment had greatly increased yield but were larger where they only doubled the yield. Daminozide increased fruit size. Hormones affected fruit mineral contents, P, K and B being reduced in the flesh and N, P and K in the stones. Stone mineral levels were much higher than those in the flesh, particularly Ca.  相似文献   

12.
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   

13.
Fruit weight is strongly correlated to ovary weight in olive as big-fruited cultivars have larger ovaries and flowers at bloom. We tested the hypothesis that larger ovaries imply stronger sinks and therefore reduce fruit set, expressed as number of fruits. Flower/fruit load per centimeter of shoot was assessed every month from flowering to harvest, on sample shoots of many different olive cultivars differing in fruit size. Data were taken for two years: 2007 and 2008. Additionally, in 2008, a fruit thinning experiment was carried out by leaving a single fruit per shoot, to assess the maximum potential fruit weight achievable by each cultivar. Results indicated that fruit size was mostly genetically determined as thinned fruits of small-fruited cultivars, although bigger than control fruits, never got as big as fruits from large-fruited cultivars, confirming that large ovaries are a prerequisite for large fruits. Among all cultivars, the number of flowers per inflorescence, the number of inflorescences, and the number of flowers per centimeter of shoot were not correlated to average flower weight while total flower mass per centimeter of shoot was positively correlated to average flower weight (i.e. large flowered/fruited cultivars had greater total flower mass). However, one month after bloom and thereafter, all parameters were negatively and exponentially correlated with fruit average weight across cultivars, except fruit mass per centimeter of shoot which was generally not correlated to fruit average weight, except in one year, at harvest, when fruit mass per centimeter of shoot was positively correlated to fruit average weight. These results suggest that fruit set is a consequence of, and inversely proportional to flower/fruit size in olive.  相似文献   

14.
Summary

Field and laboratory experiments were conducted to study if rain could wash-off pollen grains from the surface of the stigma and consequently affect the efficiency of fertilisation in loquat (Eriobotrya japonica Lindl.). Flowers of the loquat cultivar, ‘Dawuxing’, growing in the field, were emasculated, pollinated by hand with pollen of the cultivar ‘Longquan No.5’, then sprayed with water to simulate the effect of rain at –8, –4, –2 h before, –0 h (immediately before hand-pollination) , +0 h (immediately after hand-pollination), and 2, 4, 8, or 12 h after pollination. A control to which no water treatment was applied was also included in the assay. Meanwhile, additional assays were performed in the laboratory to improve the resolution of the field study by using earlier treatments. Here, treatments were performed by pollinating, immersing, and shaking a branch with flowers in a container of water in the laboratory –120, –60, –30, –0, +0, 30, 60, or 120 min before or after hand-pollination. One additional sample was immersed, shaken, then hand-pollinated, and immersed and shaken (ISPIS) again. The results showed that the numbers of pollen grains that germinated, and the percentages of fruit set, differed significantly between the –4, –2, –0, or +0 h treatments and the non-water-treated control in the field assays, especially in the case of the –0 h and +0 h treatments in which the stigmas were washed immediately before or after hand-pollination. However, the –8, 2, 4, 8, and 12 h treatments did not show significant differences from the non-treated control. On the other hand, the laboratory experiments showed that all washing treatments reduced the number of germinated pollen grains retained on the stigma, and the immersion treatments at –30, –0, +0, or 30 min as well as the additional ISPIS treatment, showed significant differences from the non-treated controls in the numbers of pollen grains retained on the stigmas. In conclusion, the results showed that adhesion of pollen grains to the stigmas in loquat was rapid and strong, and that the simulated rain treatment was not able to wash-off pollen grains completely from the stigma surface, except in the –0 h and +0 h treatments.  相似文献   

15.
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   

16.
The effective pollination period (EPP) of durian was determined by both delayed and bud pollination, during which reproductive factors affecting the EPP, e.g., stigma receptivity, pollen tube growth in the style, and ovule longevity were studied histologically. This study was conducted in three distinct locations in Thailand, namely, the Chantaburi Horticultural Research Center and two private orchards in Chantaburi and Trat provinces. Results from artificial pollination revealed that at anthesis, the durian flower is receptive and has a high fruit set ratio. A mean fruit set of 50% was obtained at anthesis in the private orchard in Chantaburi province. However, the EPP of durian was found to be very short, lasting for only one night; the fruit set from pollination on the morning after anthesis ranged from 0% to 3.4%. No fruit set occurred following pollination 24 or more hours after anthesis. When compared with the flowers of other fruit species, the durian flower has a unique feature in that it blooms overnight; the following morning, there is abscission of all parts of the flower, except the gynoecium. Thus, EPP appears to be synchronized with flower longevity. On the other hand, the durian flower was receptive several hours before anthesis. The results of chemical tests, including the hydrogen peroxide test and Perex-Test®, for the evaluation of stigma receptivity appeared to be in agreement with the EPP. However, fluorescent microscopy revealed that pollen could germinate even in the stigmas pollinated 48 h after anthesis, but the number of pollen tubes at the top of the style rapidly decreased from 34.6 (at anthesis) to 0.5 (48 h after anthesis). A correlation test demonstrated a higher correlation coefficient between the fruit set and the number of pollen than that between the fruit set and the result of Perex-Test®. This indicated that pollen tube penetration or elongation in the style was inhibited, probably due to the deterioration of nutritional support from the pistil to the pollen tubes; this can be a limiting factor of the EPP in durian.  相似文献   

17.
Applications of GA3 in May/June, when the first flush of growth was maturing, induced an extra flush of vegetative growth and initiated lateral bud break. Flower initiation was delayed and flower size reduced by the GA3. These responses were only slightly modified by additional sprays with BAP and TIBA. GA4+7 was ineffective in promoting either extra extension growth or lateral bud break, but it did reduce flower size.  相似文献   

18.
In order to increase the fruit weight of a shriveled-seed cultivar, trees of ‘Yu Her Pau’ litchi (Litchi chinensis Sonn.) growing in Taiwan were sprayed with Gibberellic acid (GA3) (ProGibb®, 20% of GA3) at 5 and 10 mg/l 14 days after full bloom (AFB) over 2 years. Both concentrations of GA3 significantly increased fruit longitudinal and transversal diameter, and fruit, aril and pericarp weight (40–41 and 37–38 mm, and 27.3–28.4, 21.7–22.7 and 5.0–5.3 g, respectively) compared with control (35–36 and 33–34 mm, and 22.3–22.4, 17.8–17.9 and 3.9–4.0 g), but had no significant effects on seed weight, percentage of aril weight of total fruit weight or total soluble solids (0.5–0.7 g, 78.9–80.3% and 18.1–19.0 °Brix, respectively). Fruit characteristics within the two concentrations of GA3 showed no significant difference. The results indicated that sprays of GA3 should be evaluated in ‘Yu Her Pau’ commercial orchards, and in other elite cultivars.  相似文献   

19.
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   

20.
Summary

Inflorescences are known to be important physiological sinks especially when they set fruit. The effect, over two successive years, of inflorescence removal on one year old wood was investigated on apple (Malus domestica Borkh.). The study was carried out on medium vigour (around 30 cm) branches of cv. Granny Smith. On one set of branches (control) the inflorescences were untreated, while on two other sets, one-third and two-thirds of inflorescences (spur leaves, bourse-shoot and flower cluster) were removed at full bloom. The first analysis investigated the fruit setting ability of remaining inflorescences. The results generally confirmed previous results on the positive correlation between the number of leaves and flowers of the inflorescence and fruit set, and also the higher fruit set on two year old wood as compared with one year old wood. On one year old wood, inflorescence removal treatments tended to increase the fruit set of inflorescences with a low number of leaves and flowers leading to a level of fruit set similar to that of inflorescences with a larger number of leaves and flowers. On two year old wood, in the following year, only the two-thirds treatment increased fruit set consistently compared with the control. A second analysis investigated the effect of inflorescence removal on lateral shoot development. It was shown that the treatments had a little effect on quantitative growth (length, diameter) of the laterals per se. On the other hand, the removal of two-thirds of the inflorescence significantly stimulated the development of fruitful inflorescences the following year. Results are discussed in relation to the local versus global physiological integration at the branch level.  相似文献   

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