Improving productivity of four fruit species by growth regulators applied once in ultra-low doses to the collar

Summary

Two growth retardants: paclobutrazol (P, Cultar) or 2,3,5-triiodobenzoic acid (TIBA) were applied once alone, or in mixtures (in a range of 5 to 20 mg per tree) to the collar of maiden plum, sour and sweet cherries and apple trees, in early spring of the second year after planting. Plum and apple trees were also treated with benzyladenine (BA) at 10 mg per tree a.i. in a mixture with P or TIBA. Sweet and sour cherry trees were treated with natural phenolic substances: phloridzin (Phi) and quercetin (Que) alone, or in mixtures with P and TIBA. A mid-stem treatment with P and shoot bending were also applied to the plum and apple trees for comparison. Measurements of tree growth and fruiting were made within 4 or 5 years. The reaction of the four species to the treatments varied according to the growth regulator applied. Plum trees responded mostly to TIBA and its mixtures with P. A strong suppression of tree growth and increased fruit productivity, as well as improved fruit quality, were observed. The TIBA application and its mixtures with P were also effective in causing growth reduction of the sweet cherry trees. Treatments with P alone, or mixed with TIBA, were effective in growth limitation of sour cherry trees. Some increase in the reproductive processes was observed only after the TIBA treatment in both species. The apple trees responded to application of mixtures of TIBA with benzyladenine (BA), or with P, and to P alone, with effective growth reduction. But only the P + BA treatment increased significantly the fruiting of apple trees, while the other treatments resulted in crops proportional to the diminished tree sizes. The mid-stem treatment did not affect plum trees but increased growth of apple trees. Shoot bending had no effect on the plum trees but increased fruiting of apple trees. The addition of Phi to half the lower P dose or TIBA, magnified growth suppression in the sweet and sour cherry trees. When applied alone Que caused a small growth inhibition but Phi produced some increase in growth of sour cherry trees. Results obtained show the possibilities of practical applications of growth regulators to the collar. Their reduced doses mixed with natural phenolic substances are equally effective in growth suppression and make fruit production safer and more profitable, especially in plum and sour cherry trees.     

Rootstock and pruning effects on first season dry weight distribution in delicious apple trees

Redchief Delicious apple trees on MM. 106 and M.9 rootstocks were left unpruned, dormant headed at planting, or summer headed 12 weeks after planting, to investigate pruning and rootstock effects on dry weight distribution between roots and shoots during the first growing season. Dormant heading stimulated new shoot dry weight and reduced new root dry weight during the first six weeks after planting. However, by 12 weeks differences in new root dry weight and new shoot dry weight were insignificant. Summer heading resulted in a significant increase in new shoot growth and decrease in new root growth. This caused the root/shoot ratio in headed trees to return to the unpruned value within six weeks after summer heading. New root growth was reduced over a longer time by dormant heading trees on MM. 106 than those on M.9. New shoot growth was increased longer in trees on M.9. Allometric constants (K) of new shoot growth relative to new root growth were significantly changed by dormant heading with both rootstocks. Summer heading had the greatest effect on K values by shifting growth heavily toward new shoots. Root/shoot ratios in all treatments for both rootstocks showed no differences 24 weeks after planting.     

Estimating Seasonal Changes in The Quantity of White Unsuberized Root on Fruit Trees

A method of estimating the length of root visible in observation windows by counting the intersections between roots and the lines of a half-inch grid, marked on the glass, is described. Seasonal changes in the amounts of white, unsuberized root present varied between different kinds of apple trees growing in the same environmental and soil conditions. The cortex of apple roots often took three months to turn brown in the winter but this interval had decreased to an average of 2-3 weeks by May and remained fairly constant at this level until the end of September. Fluctuations in the quantities of white root present during the summer thus gave a fair indication of fluctuations in the production and growth of new roots.     

Flower initiation and node development of axillary buds,growth partitioning,and bleeding sap production of young apple trees as affected by fertigation

SUMMARY

Node and flower development in axillary buds of one year old 'Elshof trees, growth and dry-matter partitioning, and bleeding sap production were examined in unfertigated field-grown trees as well as in fertigated field- and pot-grown trees. Flower initiation in axillary buds was delayed by approximately 40 d as compared with spur buds, and the critical node number within the bud was only 14 or 15 against 19 nodes in spur buds. Fertigated trees exhibited increased node development, axillary flower-bud densities, extension shoot growth and trunk increments, and decreased root/top ratios. The seasonal shoot development was markedly hastened in fertigated trees, and the amount of bleeding sap was increased. Especially, trees fertigated in pots, using a nitrogen application range of 14 to 420 ppm N, had high bleeding sap concentrations of nitrogen, phosphorus and calcium. Flower-bud initiation of apple is discussed in terms of bud development, shoot growth and root activity.     

Seasonal Changes in the Diameter of Secondarily Thickened Roots of Fruit Trees in Relation to Growth of Other Parts of the Tree

The diameters of apple and cherry tree roots, between 1·5 ft. and 6·0 ft. from the base of the tree trunk, were measured with a microscope through glass observation panels at intervals during 4 years. The rate of root thickening was low in June and was most rapid from mid-July to mid-September, whereas rapid trunk thickening occurred in June and continued until September. The period of maximum root thickening coincided with a second peak in the production of new white extension roots when the intensity of shoot growth was decreasing.

Some root thickening was detected one week after bud burst but many roots showed no thickening until July or August. At this distance from the trunk there was no progression of thickening along the root from the proximal to the distal end.     

The Reinvigoration of Apple Trees by the Inarching of Vigorous Rootstocks

Summary

The purpose of this research was to determine if established, orchard-grown apple trees that were con®ned in root-restricting membranes received adequate water for growth when irrigated. Previous data had shown positive effects of root restriction on reducing shoot extension growth in apple. Soil matric potential (Ψ_sm), leaf stomatal conductance (g) and leaf water potentials (Ψ_l) were measured over daily cycles during the period of maximum tree water use (July and August). Measurements were also made of the Ψ_sm and fruit size throughout the growing season. Daily and seasonal Ψ_sm showed that the soil within the root restricting membranes (+R) when irrigated (+I) remained closed to field capacity (<100 HPa), which was not the case for unirrigated soil within the membranes (-I +R). Ψ_l measured before dawn, showed that similar levels of drought stress were evident between irrigated and restricted (+I +R) and unrestricted (+I -R and -I -R) trees. The Ψ_sm, and Ψ_l for trees with roots within restricting membranes were significantly more negative, in the absence of irrigation (-I +R). Measurement of g showed that root restricted trees were transpiring at similar rates in the presence of irrigation (+I +R) as unrestricted trees (+I -R) with or without irrigation. Stomatal closure could not explain the increased Ψ_l observed for the restricted irrigated (+I +R) treatment compared with unrestricted (-R) trees. A reduced stomatal aperture was the most likely explanation for the reduction in growth previously observed with the restricted unirrigated trees. Fruit size was also affected by root restriction and the effect became greater as the roots became more restricted with tree age. Similarly, there was also a negative effect, in one year, of root restriction on fruit size at harvest, even in the presence of irrigation. Data show that reductions in soil water availability, Ψ_l and g, for the root-restricted trees (+I +R), were unlikely to be the causes for the previously observed reductions in shoot growth (tree size). These results imply that other factors were in operation, among which root-synthesized chemical regulators of shoot growth are the most likely candidates.     

Effects of tree age at planting,root manipulation and trickle irrigation on growth and cropping of apple (Malus pumila) cultivar Queen Cox on M.9 rootstock

Summary

The apple cultivar Queen Cox on M.9 rootstock cropped more precociously when planted as two year old trees than when planted as one year old trees, even though there were no significant differences in the sizes (leader height and branch length) of the trees at the time of planting. However, the two year old trees had larger root systems at planting. As the trees aged, those planted as one year olds grew more vigorously and bore higher cumulative yields than those planted as two year olds. Annual root pruning of the trees, commencing 15 months after planting, reduced extension shoot growth, crown volume and grubbing weights (final fresh weights of scions) severely. In some seasons root pruning increased the number of spur and terminal floral buds produced and also the final sets and yield efficiencies on the treated trees. Planting trees within semi-permeable fabric membranes also reduced extension shoot growth and tree size, but less severely than the root-pruning treatment. Root restriction increased the efficiency of fruit set and yields and also improved the grades of fruits produced. Trickle irrigation treatments increased shoot growth and tree fresh weight at the time of grubbing, but had inconsistent and small effects on fruit set and yields. Interactions between tree age at the time of planting and the root manipulative treatments were significant.     

Investigating Root Density of Plum and Apple Trees Grafted on Low-Vigor Rootstocks to Improve Orchard Management

Plum and apple trees are the most widely spread fruit trees in south-eastern Europe. The main purpose of this paper is to characterize the spatial distribution of roots in medium and course textured soils to improve orchard management. ’Stanley’ plum cultivar grafted on Saint Julien A semi-dwarf rootstock and ’Topaz’ apple cultivar grafted on M.9 dwarf rootstock were studied in a temperate climate and medium and course textured soils. The trench technique was used. There was an intense concentration of roots near the trees and the roots did not occupy the whole soil space between tree rows. The finest tree roots in both species were prevalent. Root density was higher in tree rows versus inter-rows. Both the inter-row and in-row distances can be reduced to increase tree density if light penetration into canopy is sufficient. When a full irrigation regime is applied, a soil depth of 0.8?m would be sufficient for water application, and soil depths of 0.4 to 0.6?m would be recommended for deficit irrigation; water and fertilizers should only be applied over the surface area covering most of the roots. When a more strict control on root activity is desired, the tree roots could be cut vertically at 0.5–0.8?m distance from tree rows. The results could also be used in regions and countries with similar soil texture and climate conditions.     

砂土1/4根域施用有机肥对苹果幼树生长的影响

以2 a生有机玻璃箱栽植的分根苹果幼树为材料,研究1/4根域施用不同水平有机肥对苹果幼树新梢和根系生长的影响。结果表明,6月中旬以后,10%和30%有机肥处理的新梢二次生长旺盛;20%有机肥处理春梢段节数、占总新梢节数比例、叶面积、比叶重和春梢生长量均显著大于10%和30%处理,10%有机肥处理秋梢长度、节数、叶面积和比叶重均显著大于20%处理,秋梢补偿生长旺盛;不同比例有机肥处理调控梢类组成,10%和30%处理的长梢比例分别占总新梢22.2%和25.0%,而20%处理的仅占11.8%;除6月份外,20%有机肥处理根系总长度在果树整个生长季节内均显著大于10%和30%处理。砂性土壤局部施用适量有机肥可以调控新梢生长和根系的发育,为果园土壤局部改良、集中营养供应等提供理论依据。     

苹果树矮化中间砧SH6 对幼树氮素吸收、分配和贮藏的影响

 以2 年生大田栽培矮化中间砧富士苹果（宫藤富士/SH6/平邑甜茶）幼树和乔砧富士苹果（宫 藤富士/平邑甜茶）幼树为试材,通过春季土施15N–尿素研究了SH6 矮化中间砧对苹果幼树N 素的吸收、 利用及贮藏的影响。结果表明：与SH6 矮化中间砧幼树相比,乔砧幼树长势强,净生长量大。树体各器 官的Ndff 值均表现为乔砧幼树大于SH6 矮化中间砧幼树;两种类型苹果幼树15N 分配率表现出一致规律, 即叶片中最高,新梢和粗根中次之,中心干最小,其中40% ~ 70%氮素分配给新生器官（新梢和叶）;秋 梢停长期,乔砧幼树地上部新生器官N 肥分配率（63.66%）明显高于SH6 矮化中间砧幼树（57.68%）, 乔砧幼树氮素利用率（14.32%）显著高于SH6 矮化中间砧幼树氮素利用率（8.55%）;秋季落叶后,乔砧 幼树叶片中有33.11%的氮素回撤到树体内,而SH6 矮化中间砧幼树叶片有36.92%回撤到树体内,除细根 外,各个器官均有氮素回流贮藏,其中粗根和皮层是苹果氮素主要的贮藏部位,乔砧幼树地下部氮素增 量为8.34%,明显大于SH6 矮化中间砧幼树的增量6.85%。SH6 中间砧对苹果幼树氮素吸收及回流上均 有显著的阻滞作用。     

Effect of plant growth promoting rhizobacteria on young apple tree growth and fruit yield under orchard conditions

The effects of rootstocks (M9 and MM 106), cultivars (Granny Smith and Stark Spur Golden) and growth promoting rhizobacteria (OSU-142, OSU-7, BA-8 and M-3) on the tree growth and yield at apple (Malus domestica Borkh) trees were studied in a clay loam soil in the eastern Anatolia region of Turkey in 2002–2004. Plant growth promoting rhizobacteria (PGPR) were capable of producing indole acetic acid (IAA) and cytokinin, but three of them (OSU-7, BA-8 and M-3) were also able to dissolve phosphate. Maximum shoot number of apple trees was found after inoculation with BA-8 followed by OSU-7 and M-3. All the inoculated PGPR strains contributed to the increase in fruit yield of apple when compared to control but it was strongly depended on rootstocks, cultivars and treatments. Plant growth responses were variable and dependent on bacterial strains, rootstock and cultivar and growth parameters evaluated of young apple trees. Newly planted apple trees inoculated with OSU-142, OSU-7, BA-8 and M-3 PGPR increased average shoot length by 59.2, 18.3, 7.0 and 14.3% relative to the control and fruit yield by 116.4, 88.2, 137.5 and 73.7%, respectively. Bacterial inoculation increased shoot diameter from 7.0 to 16.3% when compared to control. The production of plant growth hormones has been suggested as one of the mechanisms by which PGPRs stimulate young apple sapling growth. The growth-promoting effect appears to be direct, with possible involvement of the plant growth regulators indole-3-acetic acid and cytokinin. In view of environmental pollution due to excessive use of fertilizers and high costs of the production of fertilizers, PGPR strains tested in our study have potential to be used for the sustainable and environmentally benign horticultural production.     

苹果树不同部位新梢叶片13C同化物的去向

以5年生‘天红2号’苹果/SH40/八棱海棠为试材,对其上部、中部和下部新梢叶片进行13C标记处理,研究其产生的13C同化物的运输分配去向。结果表明：新梢的13C自留量（自身叶片 + 自身新梢）以上部新梢中最高,为91.00%,中部新梢中次之,为79.34%,下部新梢中最小,为67.39%;新梢向其它器官提供13C同化物能力大小的顺序为：下部新梢 > 中部新梢 > 上部新梢;其中向根系的13C分配率差异最为显著,由大到小依次为下部新梢 > 中部新梢 > 上部新梢;上部和中部新梢输出的13C同化物均有超过50%分配到地上部,分别为87.42%和59.79%,而仅有12.58%和40.21%分配到地下部,表现为以向地上部运输为主,而下部新梢分配到根系的13C同化物达到了75.53%,以向根系运输为主。     

苹果新根生理生化特性研究

以盆栽３年生新红星／怀来海棠（Ｍａｌｕｓｍｉｃｒｏｍａｌｕｓ）为试材，研究了生长根和吸收根的还原能力、碳氮物质代谢、吲哚乙酸氧化酶（ＩＯＤ）、过氧化物酶（ＰＯＤ）和超氧化物歧化酶（ＳＯＤ）的周年动态变化。结果表明，两类新根均于春、夏、秋形成３次吸收高峰，但还原能力的高峰只于夏秋季出现，其中夏季高峰最大；淀粉、糖、蛋白质含量及ＩＯＤ、ＰＯＤ活性随新梢旺长而降低，随新梢缓慢或停止生长而积累，氨基酸含量、ＳＯＤ活性相反；吸收根的吸收能力、淀粉、糖、蛋白质含量、ＰＯＤ、ＩＯＤ活性均显著高于生长根，但吸收根中氨基酸含量、ＳＯＤ活性却小于生长根，因而两类新根的代谢特点和功能不同，其发生数量和比例影响树势和植株的生长发育     

苹果分根交替灌溉不同水量对树体生长和水分利用效率的影响

以3 a生分根盆栽嘎拉苹果为试材,研究了不同根域交替灌溉不同水量对树体生长和水分利用效率的影响。结果表明,灌水量调控了苹果新梢二次生长的发生、生长时间和速率,每一根域每次灌水量为500 mL时,仅4/4根域灌水处理的新梢出现二次生长;灌水量为750 mL时,2/4、3/4和4/4根域灌水处理的新梢均出现二次生长;灌水量为1 000 mL时,1/4、2/4、3/4和4/4处理的新梢均有二次生长,其二次生长随着灌水根域的增多而时间提早,生长速率加快。每一根域灌水量相同时,植株主干、枝条、叶片、根系和总生物量随灌水根域增多而提高,750 mL与1 000mL根域灌水处理差异不显著。植株的水分利用效率随灌水根域的增多而降低。从确保树体正常生长和提高树体水分利用效率综合分析,2/4根域每次灌水750 mL为最佳灌溉方案。     

Observations on the Growth of Roots and Shoots of Tea (Camellia Sinensis,L.) in Southern Malawi

The construction of simple root observation trenches is described. Preliminary studies on the growth of roots and shoots of young clonal tea growing under irrigated field conditions in Southern Malawi showed that periods of maximum shoot growth were associated with minimal root growth. Observations on mature tea showed a high concentration of roots in the top 30 cm of soil but a marked reduction in active growth in this part of the profile during drought. Preliminary observations on mature tea showed a similar reduction in root growth during a period of intense shoot growth. Pruning of both newly planted and mature tea caused roots to cease growing for approximately three months. These observations are briefly discussed in relation to their probable effects on the uptake of water and nutrients     

The Gravitational Responses of Young Apple Trees

A distinctive seasonal pattern in the outgrowth of shoots was observed in upright maiden apple trees. Until midsummer, extension shoot growth was confined to the apical region of the trunk. After midsummer, vigorous shoots grew from the basal region of the trunk, and the production of these shoots coincided with a decline in growth rates of shoots in the apical region. A similar pattern of shoot growth was evident in trees grown in horizontal and inverted positions but was modified by the effects of gravity, viz. growth curvatures, effects on the symmetry of shoot production about the axis, and changes in the vigour of shoots in the apical and basal regions of the trunk. Growing trees in horizontal and inverted positions caused a reduction in terminal extension growth, but did not reduce the total amount of shoot growth compared with vertically-grown trees. Changing the orientation of the trunk caused differences in the pattern of axillary flower bud formation, but had no detectable effect on the total numbers of flower buds initiated.     

螺旋环剥对幼龄荔枝树生长结果的调控作用

‘糯米糍’和‘桂味’荔枝幼树不挂果现象相当普遍。采用螺旋环剥能显著促进成花、改善花质、减少落果、增加产量,改善品质。糯米糍、桂味幼树在生理落果期间出现旺盛的根梢生长峰,但其成年树和坐果比较正常的怀枝幼树都没有出现这种旺盛生长,表明了品种和树龄特性的差异。螺旋环剥明显减少生理落果期间的根与梢的生长量,使果实在与根、梢之间的库力竞争中获得优势,因而有利于坐果和果实生长。     

乔砧苹果断根对根系及新梢的促控研究

通过早春断根后连续3年的观察，较完整地记载了苹果断根根系的再生状况及对新梢生长的影响。调查表明，盛果期乔砧苹果在发芽前断根，当年的抑梢效果不明显，第2年表现出显著的控长效果；距主干80cm左右断根后，根系再生复原期至少需2年以上，恢复期内对果实产量及品质无不良影响。     

Effects of growth retarding treatments on apple tree growth,fruit maturation and fruit abscission

SUMMARY

Eight days after petal fall in 1991, mature 'Delicious'/MM. 106 apple trees and four days after petal fall in 1992, mature 'McintoshVMM. 106 were ringed, scored, root pruned (1 m from the trunk, two sides, 30 cm deep), or treated with ethephon (500 mg 1¹). Only ringing and scoring reduced vegetative growth. Ethephon advanced fruit maturation and fruit abscission, but root pruning did not affect the trees or fruit significantly. Mature 'Cort-land'/M.7a apple trees were root pruned 8 d after petal fall in 1991 and/or at full bloom in 1992. Root pruning reduced shoot growth, even in the year after treatment. Fruit abscission was reduced in 1991 and 1992 by root pruning in 1991, but root pruning in 1992 had no impact on abscission, in 1992. In an additional experiment, mature 'Mcintosh'/ MM.106 were root pruned 4 d after petal fall in 1991 or root pruned both in 1991 and at full bloom in 1992. Growth and preharvest fruit abscission were reduced in both the year of root pruning and the year after.     

Use of 6-benzylamino purine and Promalin for improved canopy development in selected apple cultivars

Foliar sprays of Promalin (gibberellins A_{4 + 7} + 6-benzylamino purine) applied to 1-year-old apple (Malus domestica Borkh.) trees at the 3–5-cm growth stage significantly increased lateral branching in 5 of 9 cultivars tested. Branching response ranged from 0% (‘Winter Banana’) to 131% (‘Starkrimson Delicious’) of the untreated controls. Total shoot growth was not consistently increased by 6-benzylamino purine or Promalin in tests over 3 years on spur and non-spur 1- and 2-year-old apple trees. Sprays of 50–300 mg l⁻¹ Promalin were ineffective for increased branch development. Sprays of 300–500 mg l⁻¹ increased total shoot numbers and reduced average shoot length. Sprays applied prior to new terminal growth in spring were ineffective. Treatment during periods of active shoot growth were generally effective, but periods of stress may have reduced response. Sprays were more effective for inducing lateral shoot formation than dormant heading or delayed dormant heading (pruning) (10 days after full bloom) in ‘Criterion Golden Delicious’. No difference in branching response was observed between BA and Promalin. Addition of a spray adjuvant (Buffer-X) did not affect branching response. Repeat annual single sprays of Promalin applied to dormant pruned trees were generally less effective for stimulating lateral branching than a single application in a given year. Phytotoxicity was associated with Promalin sprays at 300–500 mg l⁻¹ on ‘Delicious’.