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1.
The experiments described in this paper were designed. (1) to investigate the mechanism whereby α-naphthalene acetic acid (NAA), applied as a spray to apple trees between full bloom and two to four weeks after petal-fall, reduces the crop ; and (2) to assess the possible value of this substance as a blossom- and fruit-thinning agent.

Spraying open flowers with NAA before pollination was found to induce incompatibility between the pollen tubes and the stylar tissue, and it is considered that this may account for the reduction in set which results from spraying trees at full bloom with NAA. Applied after petal- fall, the spray caused the abortion of a large proportion of the developing seeds and this, in turn, led to an abnormally large drop of young fruitlets. The seeds appeared to be susceptible to damage by NAA only as long as the endosperm was in the free nuclear stage, a condition which, in most varieties of apple, persists until about the third week after petal-fall. As a thinning agent, NAA has the disadvantage that it tends to retard fruit growth. This effect is particularly marked when the spray is applied later than two weeks after petal-fall, and frequently offsets any increase in fruit size which might have resulted from thinning. Earlier application of the spray may, in certain varieties, cause a permanent stunting of the foliage. In the strongly biennial Miller’s Seedling, none of the thinning treatments, using NAA on individual branches, resulted in the differentiation of fruit buds in the " on ” year.  相似文献   

2.
The effects of CPPU on the growth of fruits and bourse shoots of apple were examined by targeted applications of 20 mg I“1 CPPU to fruitlets and/or bourse-shoot and spur leaves. Treating fruitlets and fruitlets-plus-leaves stimulated fruit growth to a similar extent; fruit growth rate was temporarily suppressed when only the leaves were treated. Conversely, bourse shoot growth was stimulated by leaf and leaf-plus-fruit treatments. All CPPU applications reduced the content of fruit soluble solids and induced a paler yellowish- green fruit ground colour.  相似文献   

3.
Summary

The influence of wood age, fruiting position and leaf area within the tree canopy on fruit mineral content and quality for several apple (Malus domestica Borkh.) cultivars was investigated. Size and Ca, Mg and K content of individual fruit on one-year (lateral and terminal positions), two-year and older than three-year wood were compared for cvs Royal Gala, Braeburn, Granny Smith and Fuji. Fruit on two-year spurs and one-year terminals was generally larger at commercial harvest than that on one-year laterals and spurs older than three years. Flower receptacles at full bloom were larger and fruit growth rates were greater from 60 to 100 d after full bloom on two-year spurs than on one-year laterals. Fruit Ca and Mg concentrations and contents at commercial harvest were highest for terminal fruit, but there was no consistent difference between fruit from other positions. One-year terminals had the greatest primary and bourse leaf areas, two-year spurs were intermediate and one-year laterals had the lowest areas of both leaf types. Removal of 50% of primary leaves and/or removal of bourse shoots from clusters at bloom reduced fruit Ca content at commercial harvest for two-year spurs, one-year laterals and one-year terminals. Bourse shoot removal also reduced Mg content for all positions. However there was no effect of leaf removal on fruit size or K content. Ca content of individual fruit increased curvilinearly with increasing total spur leaf area for fruit on two-year spurs and one-year terminals but not for fruit on one-year lateral clusters. Terminal fruit with total spur leaf areas and fruit size similar to those on two-year spur fruit had higher Ca content.  相似文献   

4.
Fruit-set of ‘Golden Delicious’ apple trees was found to be largely independent of seasonal differences and much more closely related to the initial number of blossom clusters, when compared with many other apple cultivars under English conditions. In one young orchard, yield became increasingly a function of trunk girth during the first 3 cropping-years, but the trees then abruptly developed a biennial rhythm. Thereafter, blossom production was negatively correlated with the number of clusters in the previous year rather than with the number of fruits.Applications of daminozide or GA3 appeared to increase or decrease, respectively, the amount of return bloom without altering the negative correlation with the number of clusters in the previous year. Chemical fruit-thinning with a mixture of carbaryl and NAA also appeared to be effective in increasing return bloom.  相似文献   

5.
SUMMARY

Adventitious shoot formation was investigated using leaf segments of in vitro cultured shoots of the apple rootstock Jork 9. Regeneration capacity was influenced by the pretreatment of the mother shoots, macroelements, hormone concentrations, the gelling agent and the carbohydrate source. The highest regeneration rate and most shoots per leaf explant resulted from young leaves on a medium based on MS macroelements supplemented with 22 µM BAP and 0.1 µM_NAA together with sorbitol, at concentrations of 165 mM or 220 mM. Sorbitol was more effective than sucrose, glucose, fructose or a combination of these sugars. A cold and dark pretreatment of the shoots enhanced the formation of adventitious shoots.  相似文献   

6.
Localized treatment of either fruitlets, pedicels or bourse shoot leaves of cv Discovery apple trees with 2 100 ppm carbaryl caused significant fruitlet abscission. Whereas carbaryl applied to a pedicel moved in significant amounts into the fruitlet, carbaryl applied to the fruitlet itself or to the bourse shoot leaves was not translocated. Carbaryl applied to a fruitlet did not enter the seeds. A possible mode of action is discussed and some practical implications considered.  相似文献   

7.
The inoculation of 40 varieties of ornamental crab apple with viruses commonly carried latently in commercial apple varieties and rootstocks killed 10 of the varieties and impaired the growth of 27 others ; only 3 were unaffected. The ornamental crabs showed varying sensitivity to chlorotic leaf spot, and platycarpa dwarf viruses. The main symptoms were line and spot patterns and distortion of the leaves, tip die-back, bark necrosis and stunting.

Viruses latent in some commercial apple rootstocks appear to be the main reason for the incompatibility between these stocks and the ornamental crabs. It is assumed that the same viruses also affect the compatibility of commercial apple varieties worked on ornamental crab seedlings.  相似文献   

8.
When leaves of M.III rootstocks were momentarily dipped in 0·004M copper sulphate solution there was an immediate rapid uptake at a rapidly declining rate (phase I), complete within a minute ; no further significant uptake occurred, though about 80% of the copper initially retained by the leaf could still be washed off its surface.

When, after a suitable interval (three minutes or more), such leaves were re-treated with the same solution there was another cycle of immediate rapid uptake, similar to phase I, but leading to rather less copper being taken up. This process could be repeated again and again, and though the copper which entered the leaf did so in a series of discrete increments of phase I uptake, the overall pattern showed all of the changes of phase that occur when a leaf is immersed in solution for long periods.

It is postulated that when leaves are dipped for the first time the copper taken up in phase I is adsorbed to two sites, only one of which (site Ia) communicates with the further sites (site II, etc.) which are eventually filled up when copper is continuously supplied to the leaves. Normally these sites are filled up through site Ia but, when the copper supply at the leaf surface is interrupted, site Ia becomes denuded of copper, and can be filled up again in another cycle of phase I when the leaves are re-treated.

Leaves treated with 0·004M copper sulphate solution under field conditions took up copper additional to the initial uptake over a period of days, presumably when the surface deposit was brought into solution by rain or dew. However, in spite of numerous occasions on which rain or dew fell, there was no further uptake over the last six days of the experiment though about a third of the copper initially present could still be washed off the leaf surface.  相似文献   

9.
The results of a fruit-thinning trial, by hand, on the apple variety Sunset on M.IX are reported. Thinning flowers at the pink bud stage, and fruitlets at one, two and three weeks after full bloom, increased fruit size and trunk-girth increment. The two earliest treatments increased the number of shoots but mean shoot length was unaffected by any of the treatments.

The increase in fruit size was due to an increase in cell number per fruit rather than to an increase in cell volume. The concept of competition between meristematic regions of the aerial parts of the tree is discussed. No residual effect of thinning on yield, fruit size or shoot growth occurred in the season following the three-year experimental period, when the trees were left untreated.  相似文献   

10.
The ability of vegetation to capture and retain atmospheric Particulate Matter (PM) is directly dependent on the interactions between PM and plant surfaces. However, the impact of individual leaf traits in this respect is still under debate due to variations in published findings. This study employed standardised experimental designs with natural and synthetic leaves in three experiments to explore the impact of individual leaf traits on traffic-generated PM accumulation whilst other influential variables were controlled. The impact of leaf size on PM deposition was explored using synthetic leaves of different sizes (small, medium and large) but with the same shape and surface characteristics (n = 20 for each category). The impact of leaf shape was examined using another set of synthetic leaves of different shape (elliptical, palmately-lobed and linear) but with the same surface area and the same surface characteristics (n = 20 for each category). PM accumulation (PM1, PM2.5 and PM10) on these leaves was quantified using an Environmental Scanning Electron Microscope (ESEM) and ImageJ software. Any differences in PM capture levels due to leaf size and leaf shape were identified using one-way Anova and Tukey’s pairwise comparison. In a subsequent experiment, equal-sized, square-shaped leaf sections obtained from four plant species (n = 20 for each species) with different micromorphology were exposed to traffic-generated pollution and any PM capture differences due to leaf micromorphology identified employing the same SEM/ImageJ and statistical approach. The results of all three experiments showed significant differences in PM accumulation between different leaf sizes (p < 0.001), between different leaf shapes (p < 0.001) and between different leaf micromorphology (p < 0.001) suggesting that all these characters are influential in the capture and retention of PM on leaves. Smaller leaves and complex leaf shapes (lobed leaves) showed a greater potential to capture and retain PM. Leaf surfaces with hair/trichomes, epicuticular wax, and surface-ridges accumulated more PM compared to smooth surfaces; of these characters, leaf hairiness/presence of trichomes was found to be the most important. Species sharing most of these important leaf traits are recommended as effective PM filters.  相似文献   

11.
The annual growth of an apple tree in the vegetative condition is distributed in a definite pattern between leaves, stems and roots ; when a crop is borne, this constitutes an additional end-point for growth materials. The disturbances in the pattern of vegetative growth caused by this additional region of utilization are described. Two-year-old apple trees were deblossomed at flowering or defruited on 30th May, and their growth was compared with that of cropping trees. The increments in weight were estimated by samples taken at treatment times.

After deblossoming, the trees made extra growth in terms of dry weight, more and larger leaves, and longer stems. The periods of greatest and least growth were the same as for cropping trees. Defruiting also resulted in extra growth, but this came later, and so was out of phase with the growth of fruiting trees. This extra vegetative growth (including more trunk thickening and root growth as well as leaves and new shoots) weighed more than the crop on the fruiting trees. Defruiting had slightly less effect than deblossoming.

The diversion of metabolites to the crop changed the pattern of growth in the rest of the tree. Cropping trees had 50% more leaf proportionate to total vegetative increment, and 50% less root, than deblossomed ones. The intervening regions varied roughly according to their position. Despite this greater leafiness of cropping trees, they produced significantly more total dry matter (vegetative growth plus crop) per unit area of leaf.

These results are attributed to the greater demanding power of the growing crop in diverting photosynthates from the lower parts of the tree and in increasing the rate of removal of photosynthates from the leaves.  相似文献   

12.
枯草芽孢杆菌生防菌剂sf-628专用助剂的研发   总被引：1，自引：0，他引：1  
【目的】为了获得枯草芽孢杆菌sf-628的专用助剂,【方法】将sf-628与6种不同的表面活性剂组合按重量比95∶5进行混配,并以菌液中的活菌量为依据进行筛选。同时采用国标GB 5549-90的方法测定sf-628与各个表面活性剂组合混配后稀释液的表面张力,并将其与苹果、梨叶片的临界表面张力进行比较分析。【结果】结果表明,苹果叶片正、反面的临界表面张力值分别为31.78 mN.m-1和33.75 mN.m-1;梨叶片的临界表面张力值分别为39.90mN.m-1和38.02 mN.m-1。活菌量的测定结果表明4种表面活性剂组合对sf-628表现为抑制作用,其余2种表面活性剂组合(Ⅲ和IV)则对其安全。将其与sf-628混配后0～1 000倍稀释液中,表面活性剂组合Ⅲ和IV达到临界胶束浓度,表面活性剂组合Ⅲ稀释液的表面张力大于苹果叶片的临界表面张力,故难以很好地在苹果叶片上润湿展布;表面活性剂组合IV稀释液的表面张力小于苹果、梨叶片的临界表面张力,故可以在苹果、梨叶片上黏着并润湿展布。【结论】表面活性剂组合IV可作为枯草芽孢杆菌sf-628的专用助剂在苹果、梨树上使用。  相似文献   

13.
Summary

Mature slender spindle ‘Jonagold’/M.9 apple (Malus × domestica Borkh.) trees were thinned using 10 mg l–1 1-naphthaleneacetic acid (NAA) or 100 mg l?1 6-benzyladenine (BA) and an axial fan sprayer at a spray volume of 1,500 l ha?1 applied to the whole canopy, or with smaller volumes, where only the upper half of each canopy was sprayed. Partial spray applications of NAA or BA (at 1,000 l ha?1, 750 l ha?1, or 500 l ha?1) to the upper half of the trees did not cause any reduction in final fruit numbers on the upper half, or on the lower half of each tree. When the whole tree was sprayed to run-off with the same thinning agent, or at 1,500 l ha?1, successful thinning on both the upper and lower parts of the canopy occurred. Good spray coverage (from 51% to 77%) was also observed on leaves at all canopy positions measured, when whole trees were sprayed at 1,500 l ha?1.The development of an innovative crop load regulation strategy was an objective of the ISAFRUIT Smartfruit Project.  相似文献   

14.
Summary

To find the most appropriate rates of application of plant growth regulator (PGR) thinning-agents for a common slender spindle apple (Malus × domestica Borkh.) orchard, different volumes of dilute 1-naphthaleneacetic acid (NAA) and 6-benzyladenine (BA) were sprayed ha?1. Mature ‘Jonagold’/M.9 trees, 3.0 – 3.5 m high and 1.2 – 1.5 m wide, planted in a single row system with 3,030 trees ha?1, were used. Significant thinning was observed in the case of dilute sprays of NAA at 10 mg l?1, or BA at 100 mg l?1, to run-off, using 2,000 l ha?1 or 1,500 l ha?1; while 1,000 l ha?1 did not result in sufficient thinning. Thinning using smaller volumes (250, 500, or 750 l ha?1) was also significant if the concentration of PGR thinner was proportionally higher (i.e., based on the 1,500 l ha?1 application rate of more dilute sprays of NAA at 10 mg l?1 or BA at 100 mg l?1). Spray distribution measurements in the crowns showed better spray deposits when higher water volumes (i.e., more dilute PGR solutions) were sprayed at all positions (bottom, middle, or top) of the canopy. At 2,000 l ha?1, 54 – 72% coverage of the leaf area was observed; but, at 250 l ha?1, coverage was only 10 – 21%. The lower 30% of the canopy was covered poorly when smaller volumes of water (250, 500, or 1,000 l ha?1) were applied. When 1,500 l ha?1 was sprayed, good coverage of the lower and upper surfaces of the leaves occurred, and no differences in canopy positions were measured. It was concluded that 1,500 l ha?1 (i.e., dilute PGR) spraying was the most appropriate volume to use when calculating the dose of NAA or BA to be applied ha?1 to common (3.0 – 3.5 m-high) mature slender spindle apple orchards on M.9 rootstock. This study was part of the ISAFRUIT Smartfruit Project, aimed at improving existing methods for apple crop regulation with more precise use of PGR thinning agents and with minimum impact on the environment.  相似文献   

15.
When apple leaves, either detached or still attached to the tree, were immersed in solutions of copper sulphate, at least four successive phases were distinguishable in the graph relating uptake with time, namely :

Phase I, when copper was taken up at a rapidly declining rate during the first 30 seconds or so of immersion, and adsorbed.

Phases II and III, which were both linear-with-time uptakes, II being faster than III, and of a rate proportional to the applied concentration ; the length of time occupied by phase II increased as the applied concentration was reduced. The length of time occupied by phase III, and the amount of copper taken up in this phase, both varied markedly from experiment to experiment.

Phase IV, in which copper was taken up at a rate comparable with that of phase II whilst material from within the leaf was simultaneously released into the solution in which the leaves were immersed.

An increase in temperature from 0° to 30° C. had little effect on the rates of uptake in phases I and II, but a further increase of 6° C. led to a considerably faster uptake in phase II.

The rate of uptake in phase II was lower for leaves of M.III rootstock than for leaves of Cox’s Orange Pippin.  相似文献   

16.
草酸复合清洗剂对红富士苹果贮藏品质的影响   总被引：12，自引：1，他引：11  
 研究了以草酸(OA) 为主剂, 二氧化氯(ClO2 ) 、氯化钠(NaCl) 等为辅剂的清洗剂10.0g·L-1OA + 10.0 g·L-1NaCl + 9 mg·kg-1ClO2 + 0.02%吐温-20对红富士苹果的清洗效果及洗后对果实贮藏品质的影响。结果表明: 草酸复合清洗剂对红富士苹果表面的农药、重金属、菌落的清除效果好, 且经该清洗剂清洗后的果实在(0 ±1) ℃冷藏, 贮藏品质高于对照, 延缓果实硬度的下降, 推迟呼吸高峰和乙烯释放高峰的到来时间, 降低乙烯释放量, 延缓可滴定酸、可溶性固形物的降解速度, 并有降低失重率和腐烂率的作用。  相似文献   

17.
When apple leaves, either detached or still attached to the tree, were immersed in solutions of copper sulphate, at least four successive phases were distinguishable in the graph relating uptake with time, namely :

Phase I, when copper was taken up at a rapidly declining rate during the first 30 seconds or so of immersion, and adsorbed.

Phases II and III, which were both linear-with-time uptakes, II being faster than III, and of a rate proportional to the applied concentration ; the length of time occupied by phase II increased as the applied concentration was reduced. The length of time occupied by phase III, and the amount of copper taken up in this phase, both varied markedly from experiment to experiment.

Phase IV, in which copper was taken up at a rate comparable with that of phase II whilst material from within the leaf was simultaneously released into the solution in which the leaves were immersed.

An increase in temperature from 0° to 30° C. had little effect on the rates of uptake in phases I and II, but a further increase of 6° C. led to a considerably faster uptake in phase II.

The rate of uptake in phase II was lower for leaves of M.III rootstock than for leaves of Cox’s Orange Pippin.  相似文献   

18.
''''宫藤''''富士苹果叶片离体再生体系的建立   总被引：1，自引：0，他引：1  
邢倩  李天红 《北方园艺》2007,(11):13-15
以'宫藤'富士苹果组培苗为试材,对叶片离体再生体系进行了研究.不同激素种类、浓度配比及叶片放置方式的试验结果表明:以MS为基本培养基添加5.0 mg/L 6-BA、1.0mg/LNAA叶片远轴面接触培养基(叶片反放)可得到最高的再生效率,为73.3%,6-BA对叶片再生效果要好于TD2,且提高NAA浓度并不能提高TDZ对再生频率和再生叶片平均再生芽数的影响.再生植株在生根诱导培养基(1/2 MS 1.0 mg/L IBA)、生根培养基(1/2 MS)上进行培养后移入营养土成活率可达100%.  相似文献   

19.
The pressure chamber technique has been used for rapid measurement of sap tension in the petioles of apple, raspberry and blackcurrant leaves in the field.

When the soil moisture tension was relatively low, the diurnal trend in sap tension in the petioles of apple leaves followed very closely the relative evaporation rate.  相似文献   

20.
以番茄品种‘宝发008’为试材, 通过无土栽培试验系统研究了2, 4-D、烯效唑、水杨酸、云大-120、萘乙酸、爱多收6种植物生长调节剂( PGR) 对番茄生长的作用效应。结果表明, 经1 500倍云大-120、5 mg·kg-1萘乙酸+ 3 000倍爱多收处理后, 番茄根系的氯化三苯基四氮唑( TTC) 还原强度提高到0.623和0.558 mg·h-1 ·g-1 , 与对照(0.259 mg·h-1 ·g-1 ) 相比差异达到极显著水平, 对番茄叶片净光合速率、茎秆生长量和果实产量也有影响。  相似文献   

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