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1.
Girdling in October of small or large fruitless branches increased 2–3-fold both starch content of leaves and flower numbers as compared with ungirdled ‘Murcott’ mandarin trees. Autumn girdling and GA3 treatments were both effective and additive in increasing starch contents of leaves and twigs of ‘Shamouti’ orange trees. GA3, however, had the expected effect of depressing the reproductive inflorescences in both girdled and ungirdled branches, while girdling had the opposite effect. Girdling and fruit removal in October also additively and dramatically increased flower production in ‘Murcott’. Lowtemperature regimes in a phytotron caused young ‘Minneola’ budlings to flower earlier in the season and more profusely, while having no effect on starch content of leaves and twigs. The interactions of increased carbohydrate content and gibberellin in the control of flower formation in citrus are discussed.  相似文献   

2.
Summary

Excessive premature abscission of developing fruitlets in UK cherry orchards often results in low fruit yields. An improvement in our understanding of the underlying causes of embryo abortion and fruitlet abscission will help rationalize effective remedies to this problem. The aim of this study was to determine the effects of limiting the availability of leaf-derived assimilates, during critical stages of fruitlet development, on the severity of fruitlet abscission. Experimentally, this was achieved by isolating individual “spur units” (short shoots (<10 cm) with leaves and fruit) from the tree by girdling (severing the phloem connections) branches on either side of the unit. In this way, the developing fruitlets within the associated spur would be able to derive their assimilates only from the associated spur leaves. Spur units with different total leaf areas and variable numbers of developing fruitlets were chosen to achieve a wide range of potential source and sink strengths. The spurs analysed varied in leaf number from 4–9 leaves as spur leaf area increased. The largest variability in the spur leaf area number relationship occurred in spurs with 6–7 leaves. When initially determining the total leaf area per spur in May, there was no obvious relationship with fruit number per spur. Subsequent analysis of the relationship between spur leaf area and fruit number per cluster showed that fruit had been lost from spurs with the smallest leaf areas. Spurs girdled later in the season in June also showed no obvious relationship between spur leaf area and fruit number. As with spurs girdled in May, those manipulated in June lost fruit from spurs with small leaf areas. By July, there was a positive curvilinear relationship between spur leaf area and fruit number for girdled spurs. Neither total nor average fruit fresh weight per spur, at harvest, could be related to spur leaf area. The average individual fresh weight of fruit in a spur was, however, limited by the number of fruit within that spur. When spurs were girdled, fruit loss was shown to take place preferentially where the spur leaf area per fruit was low. From this analysis, it was possible to predict which girdled spurs would lose fruit, using the calculated ratio of spur leaf area per fruit. It is concluded that fruit retention, not size, appears to be limited by the availability of leaf-derived assimilates.  相似文献   

3.
The optimum leaf number: fruit ratio in various mango cuitivars was sought by isolating individual fruits with known numbers of supporting leaves by shoot girdling. 14CO2 feeding experiments showed a higher rate of carbon fixation in the leaves of girdled shoots than of control shoots but the translocation of 14C assimilates to the developing fruits on the girdled and control shoots was comparable. Starch accumulation in the leaves was reduced by shoot girdling. The stomatal resistance of the leaves of girdled shoots was comparable to that of leaves on control shoots. In all the cuitivars studied it was observed that 30 leaves, the maximum available on a shoot, could not support the growth of a single fruit to normal size. The results also show that fruit development depends not only on the current assimilates but also to a great extent on reserves. The utilization of reserve metabolites from vegetative organs during the ‘on’ year could be a contributing factor towards biennial and erratic bearing.  相似文献   

4.
Summary

Changes in water and dry-matter content of developing mango fruit (Mangifera indica L. ‘Lirfa’) were investigated over a single season in Réunion Island, along with the effects of leaf:fruit ratio (10, 25, 50, 100 and 150 leaves per fruit on girdled branches). As the fruit developed, about 8–13% of fruit water weight was in the peel compared with 78–86% in the pulp and 6–9% in the stone. When the data were expressed on a dry-weight basis, 12–20% was in the peel, 60–70% was in the pulp and 18–20% in the stone. At harvest, larger fruit, on treatment 100, had a higher proportion of weight in the pulp. Good relationships between water and dry weight of each fruit component were found, regardless of the treatment. They showed that the rate of water accumulation decreased when the dry weight increased and that the dry-matter content increased as the fruit developed as well. Increasing leaf:fruit ratio to 100 leaves per fruit improved fruit yield by 300 g and pulp dry-matter content by 6%, for a total of 550 g and 20% at harvest. Fruit quality as estimated by pulp dry-matter content could be calculated easily during the changes in fruit weight over the season. Moreover, this indicator could be useful to assess the maturity of mango fruit.  相似文献   

5.
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   

6.
Six-branched trees were deblossomed on alternate branches and various defoliation treatments given. For the period of 7 to 30 days from the time of treatment, defoliations increased the compound-interest rates of fruit drop. After this period these rates of drop became equal to those of untreated trees and the relative differences in crop numbers established by this time persisted until harvest though the actual numbers still fell. The earlier in the season that the defoliations were applied the greater were the relative differences. The removal of spur leaves from branches bearing fruit caused greater drop than the removal of spur leaves from neighbouring deblossomed branches. The removal of leaves from extension and bourse shoots of fruiting or deblossomed branches had no significant effect upon fruit drop or shoot growth.

The removal of all flowers from alternate branches at mouse-ear caused more shoots to grow from these branches than from branches allowed to fruit. Removal, at pink bud, of spur leaves from either fruiting or non-fruiting branches increased the number of shoots on both branches, but removal deferred till later in the season had no effect.  相似文献   

7.
Flower clusters were removed at full bloom from ten year old ‘Cox’s Orange Pippin’ trees on M.9 rootstocks, over the whole tree, on alternate branches or on whole sides. Mean fruit weight per tree at harvest was linearly dependent on leaf area per fruit and on light interception per fruit, both relationships accounting for over 90% of the variance. These relationships did not differ between treatments, implying either a mobile pool of carbohydrate or photosynthetic adjustment within the tree to crop load. Measurements of leaf photosynthesis in July and September showed no statistically significant differences in photosynthetic rate of spur or extension shoot leaves on bearing or non-bearing branches. Although the treatments caused no overall effects on shoot growth or leaf area per tree, sides of trees without fruit had greater leaf area and shoot growth than did sides bearing fruit. Fruit mineral composition and percentage dry weight were not affected by treatment except where the treatments significantly altered fruit size. In the following spring, although the treatments did not affect the total number of flower buds produced, branches that were deflowered in the previous spring carried significantly more flower buds than did branches which had cropped.  相似文献   

8.
Trunks of 8-year-old vigorous ‘Fuyu’ persimmon (Diospyros kaki Thunb.) were girdled to a 1 cm width on April 20 and June 10 2004. Tree growth and fruit characteristics were monitored for two years, with special emphasis on the carry-over effect in 2005. Girdling reduced trunk and shoot growth especially of April-girdled trees over two consecutive years. However, the most significant effect of girdling was in the occurrence of water sprouts: a control tree had 29.5 in 2004 and 27.3 in 2005, whereas the April-girdled trees had only 0.3 and 5.3, respectively. Girdling increased fruit set by nearly 50% and enhanced fruit colour in 2004 only. Girdling date did not significantly affect fruit size and soluble solids for two years. Fruit flesh of girdled trees in 2004, especially in the April-girdled trees, had lower N and P concentrations. The levels of starch, soluble sugars, and inorganic elements in flower-bearing distal buds measured just before new growth in 2005 were not significantly altered by the girdling in 2004.  相似文献   

9.
Experiments were conducted to evaluate the effects of calcium acetate on defoliation and fruit drop of ponkan (Citrus reticulata Blanco) and Meiwa kumquat (Fortunella crassifolia Swingle) trees treated with 2-chloroethylphosphonic acid (ethephon). Ethephon at 200 or 300 p.p.m. caused about 20% defoliation of ponkan trees, while this defoliation was materially alleviated by an addition of 0.05 M calcium acetate to the ethephon solution. Acceleration effects on fruit color did not differ with ethephon or ethephon + calcium acetate treatments. Ethephon at 400 p.p.m. caused about 30% fruit drop in kumquat trees, and an addition of 0.05 M calcium acetate to the solution almost completely prevented the fruit drop. Fruit color of kumquat was most advanced by the use of ethephon alone, and the addition of calcium acetate decreased the effect slightly.  相似文献   

10.
Summary

Levels of abortion of reproductive organs (i.e., buds, flowers, and young fruits) in sweet pepper plants (Capsicum annuum L.) are high, and cyclical fluctuations occur in fruit set. Stages susceptible to abortion are very young buds (< 2.5 mm), buds close to anthesis, and flowers and fruits up to 14 d after anthesis. An overview of factors and processes involved in flower and fruit abortion in sweet peppers is presented. More light, higher CO2 concentrations, and lower planting density, increase the availability of assimilates per plant, and decrease fruit abortion. The cyclical pattern in fruit set is caused by changes in demand for assimilates. High flower abortion occurs when fast growing fruit (at approx. 3 weeks after anthesis) are present, due to competition for assimilates. Fruit set increases when fast growing fruit are almost mature and have a low assimilate demand. Prior to abortion, auxin export from the reproductive organ diminishes, ethylene production increases, and lower levels of activity of sucrose-cleaving enzymes are found. Severe water stress and low nutrient supply also increase abortion levels. Low night- and high day-time temperatures hamper pollen development, causing low seed set, which can result in fruit abortion. Two theories have been used to explain abortion: unbalanced demand for and supply of assimilates, and hormonal dominance of developing fruit over young fruit. Attempts to prevent abortion or to diminish the cyclical pattern of fruit set have not yet been successful, but new suggestions are presented.  相似文献   

11.
The effect of four times of limb girdling on fruit and tree response was examined on ‘Mayfire’ nectarine (Prunus persica (L.) Batsch). Girdling prior to Stage II of fruit growth reduced the lag phase associated with Stage II, and caused peak fruit growth rates to occur earlier in the season than on later girdled or ungirdled trees. Optimum response was obtained by girdling prior to Stage II, when fruit seed length was approximately 10 mm. Girdling at this time increased fruit weight by 22.5% and more than doubled the percentage of fruit in the largest three size categories. Maturity, measured as soluble solids concentration, was increased by 42%. Shoot extension growth was reduced only by early girdling. Leaf weight per unit area was increased, and leaf nutrient concentrations were decreased by all girdling treatments. Leaf conductance to water vapour (g,) was not affected when measured 8 days prior to and 78 days after harvest. Fifteen days after harvest, g, was decreased in all girdling treatments.  相似文献   

12.
The overall objective of this work was to improve fruit quality, break alternate bearing and reduce hand thinning using fewer chemicals in fruit crops. A device was constructed for mechanical thinning, which consisted of three independent horizontal rotors with ropes and freely adjustable angles on a frame, mounted on a front three point hitch and powered by the tractor hydraulics. This can be adapted to any fruit tree trained as spindle, Solaxe, (tall) vertical axis or fruit wall (le mur fruitier) irrespective of rootstock employed. Rotor speed varied from 300 to 460?rpm at either 5 or 7.5?km/h tractor speed. Eight-year-old or twelve-old apple trees cvs. ‘Gala’ and ‘Golden Delicious’ were mechanically thinned in 2007 between pink bud and full bloom (flower bud stages 6–8 or F1–F2) near Bonn, Germany; non-thinned and hand-thinned apple trees of the same block and variety served as control. Mechanically thinned flowering branches showed a similar amount of ethylene efflux (0.4–0.6?ppm C2H4/branch) as non-thinned flower branches, preventing potentially unexpected subsequent fruit drop, except for those removed by the rotors. The impact of the horizontal rotors on the branches was from the upper side and removed excessive flowers right to the tree trunk viz. the centre of the tree canopy, where fruits of lesser quality are expected leaving 2–3 flowers per cluster. Leaf damage was less than??10%, even at the fast rotor speed of 420?rpm, which was associated with negligible wood injury. Mechanical thinning induced firmer and sweeter fruit, i.e. tastier apples with longer shelf life, relative to control fruit from non-thinned apple trees. The greatest efficacy in terms of final fruit quality in the grading/sorting was achieved by a rotor speed of 360?rpm at a tractor speed of 5?km/h: Fruit mass increased by up to 20?g and the proportion of fruit larger than 70–75?mm by 10–30% compared with the fruit from non-thinned trees. Mechanical thinning with this newly constructed device led to a 10–20% reduction in yield, but increased returns due to better fruit size and colouration in apple with the potential to overcome alternate bearing.  相似文献   

13.
‘糯米糍’荔枝碳素营养储备动态与坐果的关系   总被引：2，自引：1，他引：1  
 以10～12年生的‘糯米糍’荔枝(Litchi chinensis Sonn. ) 为材料, 研究了高产树(60～65 kg·株- 1 ) 和低产树(5～10 kg·株- 1 ) 不同部位(叶片、各级枝条和主干) 碳素营养储备(淀粉) 的差异及季节动态; 分析了不同果实发育阶段树体碳素营养水平与坐果率的关系。结果表明, 果实成熟时高产树各部位的淀粉含量均低于低产树, 而可溶性糖含量高于低产树。果实采收后, 低产树早于高产树抽发新梢。入冬季前(11月底前) , 低产树和高产树分别抽发了3次和2次秋梢。7～11月秋梢生长发育期间, 高产树和低产树均无显著淀粉积累, 11月中旬以后枝梢生长停滞期间, 各部位, 尤其是4 cm直径以内的枝条大量积累淀粉, 在花穗发育前达到高峰。之后, 随花穗发育、开花及坐果而持续降低。高产树和低产树各部位淀粉高峰并无明显差异, 表明坐果量对树体碳素营养储备的累积并无明显的长期影响。叶片、主枝和主干积累的淀粉含量较低, 总体相对稳定; 而4 cm直径以下的枝梢淀粉含量变化剧烈, 说明这些枝梢是更为活跃的碳素储备库。本研究还表明, 坐果早期(花后3周内) 枝条(2 cm直径) 的淀粉含量与该枝条上最终坐果率呈显著正相关, 而果实发育中期(花后8周) 枝条淀粉含量与坐果率无关, 说明早期果实发 育一定程度依赖树体碳素营养储备, 而中后期果实发育几乎不依赖树体储备。  相似文献   

14.
在纽荷尔脐橙果实膨大期,选取1年生双果枝、单果枝和营养枝,晴天测定源叶净光合速率(Pn)、气孔导度(Cond)、蒸腾速率(Trmmol)、胞间CO2浓度(Ci)和叶面温度(Tleaf)等生理指标,探讨挂果对源叶光合特性的影响。结果表明,挂果水平对源叶Pn、Cond、Trmmol有显著影响,对Ci和Tleaf无明显影响;上午以挂果多的枝条的源叶Pn、Cond、Trmmol峰值更低,下午则呈相反的趋势。不论枝条挂果多少,源叶Pn日变化呈典型的"双峰"曲线;Pn与Tleaf呈抛物线相关,当叶温达36℃左右时叶片光合作用最强。  相似文献   

15.
Yield, fruit quality, growth and the levels of 12 elements in the leaves were measured for 12-year-old Marsh Seedless grapefruit trees on six rootstocks. Trees on rough lemon and Cleopatra mandarin were larger than those on sour orange and consistently produced 67 and 23 per cent more fruit respectively than on sour orange. Trees on Palestine sweet lime, Troyer and Morton citranges were the least productive. Three-year means of total soluble solids ranged from 9·4 per cent for fruit from trees on Palestine sweet lime to 11–2 per cent on Cleopatra mandarin. Fruit size was good on all rootstocks but effects of rootstock on levels of Mg, Na, Cl and B in the leaves were statistically significant.  相似文献   

16.
Summary

The effects of different timings of fruit thinning at the lower nodes (nodes 4 to 7) on fruit growth and abortion at higher nodes were investigated in a gynoecious, parthenocarpic cultivar of cucumber (Cucumis sativus L.), ‘NK x AN8’. Fruits at the lower nodes were removed 0, 5, 10, 15 and 20 d after anthesis of flowers at node 8 (DAA8).

Total leaf areas and growth patterns of individual fruit were then monitored. When fruits at nodes 4 to 7 were thinned 0 or 5 DAA8, all fruits at nodes 8 to 12 grew to commercial size, without fruit abortion. When fruits were thinned 10 DAA8, the fruits at nodes 8 to 12 ceased to grow after anthesis, but growth was restored a few days after fruit thinning. Fruit thinning at 15 or 20 DAA8 forced most fruits at nodes 8 to 12 to abort, while fruits at node 13 and above ceased to grow for a while, but resumed growth after fruit thinning. In all treatments, total leaf area increased with time throughout the experiment. High fruit load depressed the rate of growth of leaf area slightly, 65 to 75 d after sowing. Fruit load (fresh weight) per leaf area was about 50 mg cm–2 just before fruits at nodes 4 to7 were thinned at 20 DAA8.These results suggest that fruit abortion occurs if fruits at the lower nodes persist for a long period, and fruits at the middle nodes senesce before enlargement. Fruit thinning at the lower nodes can restore the growth of fruits in the stagnant growth phase within 10 d.  相似文献   

17.
Summary

The apple rootstocks M.9, M.26, and MM.106 were evaluated for their efficiency in bringing ‘Discovery’ apple trees into production. The experiment, carried out over a ten- year period compared two planting densities at 1666 and 3333 trees per ha. Tree vigour differences between rootstocks were measured in term of trunk growth, tree volume, weight of branches pruned off and final weight of the above-ground parts of the trees. Fruit production is presented both as total yield and as the weight of first class fruit. Fruit colour development is also shown. Cropping efficiency is calculated and presented in relation to the different vigour measurements. The results confirm that ‘Discovery’ is slow to come into production. M.9 was the most productive rootstock, but due to vigour differences MM.106 gave the same yields per tree, although the latter had the lower yield efficiency. M.26 performed poorly; its vigour was similar to M.9 but it produced the lowest yields.  相似文献   

18.
Canopy leaf to fruit ratio (L:F) of 6-year-old ‘Lapins’ sweet cherry trees on Gisela 5 rootstock was manipulated at the end of stage II (38 DAFB) of fruit development. While control trees showed a L:F ratio of 0.7:1 without alteration, on other trees young fruit were manually removed to yield L:F ratios of 2:1 and 3:1, respectively. All leaves and young fruit on trees were counted 30 DAFB. The effect of altering the source–sink ratio of whole trees on sweet cherry fruit quality parameters (fruit increment, fruit mass, color, total soluble solids content, contents of individual sugars and organic acids) was evaluated in the study. High leaf area to fruit (LA:F) ratios influenced significantly darkest fruit color, higher fruit mass, higher total soluble solids content and higher ratio between sugars and acids, which corresponded to better ripening stage. Contents of glucose, fructose and sorbitol, but not sucrose, sum of individual sugars, and the content of malic acid differed significantly among fruit of the different treatments. Fruit of the most advanced maturity stage (treatment 3:1) had the highest quality. Each day of improved L:F ratio counts towards better sweet cherry fruit quality. The results show that low L:F ratio influenced prolonged ripening process and delayed fruit maturity of ‘Lapins’ sweet cherry.  相似文献   

19.
Abstract

The optimum leaf number required for normal fruit growth in the regular bearing mango cultivar ‘Amrapali’ and the biennial bearing cultivars ‘Chausa’, ‘Dashehari’ and ‘Langra’ were studied by isolating individual fruits with known numbers of supporting leaves by shoot girdling at the time of fruit set. There were significant differences in the leaf area (249.01-1817.10 cm2), fresh weight (7.0-77.0 g) and dry weight (3.7-50.0 g) of leaves on shoots having 30, 20, 10 and 5 leaves as compared with control in different cultivars. In both types of cultivars, there was a progressive reduction in fruit size in terms of total fruit, pulp, peel, and seed weight with decreasing numbers of supporting leaves, however, a minimum reduction (2.4%) in fruit growth in ‘Amrapali’ was noticed with 30 supporting leaves. A nonsignificant difference in photosynthetic rate with varying number of leaves was found but its efficiency in leaves was higher in ‘Amrapali’ as compared with biennial bearing cultivars. Starch accumulation in the leaves was reduced by shoot girdling. The stomatal resistance of the leaves of girdled shoots was comparable with that of leaves on control shoots. In all the cultivars except ‘Amrapali’ it was observed that 30 leaves, the maximum retained on a shoot, could not support the growth of a single fruit to normal size. The data on rate of photosynthesis in different pool size of leaves and fruit growth in girdled and nongirdled shoots clearly show that fruit development depends not only on the current assimilates but also to a great extent on reserves. A 14CO2 feeding experiment showed a higher rate of carbon fixation in the leaves of girdled shoots than in the control shoots, but the translocation of 14C assimilated to the developing fruits on the girdled and control shoots was comparable. The results also indicated that developing fruits are major sinks for current photosynthates as more than 60 percent of the 14C exported from the treated leaf was found in the fruit in all instances.  相似文献   

20.
荔枝常因幼树花而不实而颗粒无收.糯米糍品种4年生幼树盛花期主干环剥,并保持不愈合至采果.对照树全年根、梢各有3个生长期,环剥树采前无根、梢生长;对照树有4次生理落果峰,环剥树第2、3落果峰不明显,采前落果峰也很低.研究认为荔枝幼树根系的“库”力在竞争中占优势,根与梢的生长相克又相促,果实在竞争中处于劣势,环剥完全抑制了根与梢的生长,使果实在“库”力的竞争中得以转弱为强.  相似文献   

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