Response of secondary bloom of ‘Bartlett’ pear (Pyrus communis L.) to pruning

Summary

Type V secondary bloom of pear (Pyrus communis L.) is associated with pruning and is frequently infected by fire blight (Southwick et al., 2000). The goal of this research was to determine which pruning practices would most likely be associated with subsequent Type V secondary bloom. Pruning date, shoot age, type of pruning cut and shoot orientation were varied and effect on Type V secondary bloom assessed. In both 1998 and 1999, dormant pruning was more likely to result in Type Vs than summer pruning or pruning one month after harvest. Pruning one week after harvest in 1998 was as likely to lead to Type Vs as dormant pruning, but was less likely in 1999. The likelihood that Type Vs would occur was lowest from 49 to 89.d from full bloom (DFB) and at 175 DFB in 1998. The lowest likelihood of Type Vs in 1999 was found on shoots pruned at 83 or 185 DFB. The likelihood for Type Vs rose with increasing shoot age from one to four years, but there was no difference between three- and four-year old shoots. In 1998, stub cuts (severe heading) were more likely to have Type Vs than head cuts when pruning two year old shoots, but not for one year old shoots. In 1999, type of pruning cut had an inconsistent effect on the likelihood for Type Vs and was not the same for each shoot age. NAA applied to summer pruned shoots completely prevented Type Vs from occurring and almost completely stopped Type Vs when applied to dormant pruning cuts. Summer pruning from 50 to 90 DFB or pruning one month after harvest and the application of NAA to pruning wounds may be strategies for reducing the occurrence of Type V secondary bloom.     

修剪部位对二年生切花月季产量和质量的影响

通过对3种2 a生切花月季进行修剪处理。结果表明:不同修剪部位对不同品种切花月季产量和质量的影响不同。在七叶中部修剪时,能明显使花枝直径、花枝长度和花蕾直径增加,但发枝数和发枝时间都减少。     

Root growth following defruiting improves peach tree water status

Summary

Tree growth and water status throughout the growing season and after fruit removal were studied in container-grown peach trees. Trees with fruit (F) and defruited (DF) trees were sampled destructively at bud break (8 March), 1 month after fruit removal (3 June), at harvest (6 August), and before leaf fall (15 October) to determine the mass of leaves, current season shoots, branches, trunk, and the entire root system. Tree water status was determined from the mid-day stem water potential (SWP) the day before each sampling date. Root growth in DF trees was greater than that observed in F trees, while the above-ground biomass was similar in DF and F trees. DF trees therefore had lower leaf:root biomass ratios than F trees throughout the fruit growing season. Environmental factors did not fully explain the seasonal variations in SWP, but there was a significant correlation between leaf:root biomass ratios and SWP. Reductions in leaf:root biomass ratios were accompanied by increases in SWP and, ultimately, DF trees had higher SWP values than F trees in mid-Summer. Improvements in tree water status following fruit removal can be explained, in part, by additional root growth.     

The effect of pre-planting desiccation stress and root pruning on the physiological condition and subsequent field performance of one year old Prunus avium and P. cerasifera seedlings

Summary

Severe desiccation of dormant seedlings of wild cherry (Prunus avium) and cherry plum (P. cerasifera) did not affect their immediate survival, but caused significant reductions in subsequent shoot growth and root volume which were not recovered in a single growing season. Damage to the fine roots, as indicated by the physiological plant quality measures of tetrazolium absorbance and root electrolyte leakage, increased rapidly over drying periods of ca. 6 h, further damage requiring progressively longer periods of desiccation. Root pruning prior to planting did not mitigate desiccation damage and severe pruning was highly injurious to subsequent growth. Generally the removal of the fine roots was equivalent to a relatively short desiccation period, but pruning of fine roots prior to, instead of after, desiccation in P. cerasifera resulted in more lateral shoots, possibly indicating the production of growth retardant substances by the dried root systems. All measures of physiological plant quality at the beginning of the growing season were effective as predictors of plant performance at the end. In the species tested, the most cost-effective routines are likely to be fine root electrolyte leakage and root moisture content, with tetrazolium testing and stem water potential measurements requiring both greater reproducibility and more sophisticated equipment.     

厚皮甜瓜冬春茬栽培整枝方式研究

为了探求不同栽培整枝方式对日光温室冬春茬厚皮甜瓜熟性、产量、品质和商品性状的影响,进行了4种栽培整枝方式比较试验。结果表明:甜瓜采收期以爬地栽培单蔓整枝方式最早,比吊蔓栽培单蔓整枝方式和爬地栽培双蔓整枝方式早3d,比对照爬地栽培3蔓整枝方式早8d。单果质量、总产量、可溶性固形物含量均以吊蔓栽培单蔓整枝方式最高。吊蔓单蔓方式单果质量(755g)高出对照335g;667m2总产量达2926kg,比对照增产56.6%;中心可溶性固形物17.5%,高出对照2个百分点;且甜瓜果面光洁,果色均匀,果形周正,口感风味好,商品性状优良。据此,建议冬春茬厚皮甜瓜保护地栽培宜推广吊蔓单蔓整枝栽培方式,以取得优质高产高效。     

Further studies on graft-induced off-season flowering and fruiting in mango (Mangifera indica L.)

Summary

Defoliated shoots of cvs Alphonso, Dashehari, Totapari etc. (receptors), could be induced to flower within four weeks during the off-season by veneer grafting them to leafy shoots of the off-season flowering cv. Royal Special (donor) during the non-flowering season. Experiments on defoliating the donor and receptor shoots revealed the crucial dual role of the leaves in flowering. In the ‘floral cycle’, leaves from the donor promoted flowering, whereas leaves on the receptors, in the vegative phase, were inhibitory, and prevented graft-induction of the receptors. Thus, for graft induction, leafy donors and defoliation of receptors were essential. The inhibitory effect of the leaves on the receptors was localized and did not affect flowering of the donor shoots’ The similarity between these findings and those in the herbaceous, day-length sensitive species strengthens the view that flower formation is controlled in the same way in herbaceous and in woody perennial species. A minimum threshold of the floral stimulus appeared to be another requirement for an optimum flowering response. This was concluded from an experiment in which the leafy receptors were defoliated on different dates during the off-season flowering cycle. At the end of cycle, the defoliated receptors produced small panicles, and finally only vegetative shoots, probably indicating sub-threshold levels of the stimulus. Bud activity at the apex in the receptor was also an important pre-requisite for graft-induction. Some veneer-grafted scions which remained dormant during the flowering cycle of the donor and which sprouted much later after the completion of off-season flowering, ‘escaped’ the stimulus and invariably turned out to be vegetative. It is postulated that the cyclic synthesis of the floral stimulus in the leaves in an inductive cycle, and the gap between two such cycles, mainly decides the flowering behaviour of mango cultivars—biennial, annual and multiflowering. Two other requiremets are the absence of non-induced leaves and the synchronization of meristematic activity in the bud with the inductive cycle. Juvenile shoots from one to four year old seedlings could not be graft-induced—unlike the shoots from mature, six year old seeding trees. This juvenility effect continued into the second year when defoliation of the receptor shoots had no effect and failed to induce them to flower.     

密植桃园的主干形修剪栽培试验

连续五年密植桃园的主干形修剪试验表明：主干形修剪技术用于密植栽培桃树早结果早丰产效果显著。‘春花’成苗定植后第二年产量达1300kg·666．7m-2,第三年为1500kg·666．7m-2,第四年为2250kg·666,7m-2,第五年为1750kg·666．7m-2;‘湖景蜜露’定植后第二年和第三年产量为1021kg·666．7m-2和1019kg·666．7m-2;‘锦绣’定植后第二年产量为120km·666．7m-2,第三年为1204km·666．7m-2,第四年为1876km·666．7m-2;‘沪463’定植后第三年产量为47．5kg·666．7m-2,第四年为2125kg·666．7m-2。主干形修剪夏季摘心可促进早期副梢的萌发,利用副梢坐果,均衡树势。主干形修剪对桃果实的品质有一定的影响,使果实相对变小,单果重减轻,要注意疏花疏果,加强肥水管理。     

同步叶片修剪对温室番茄干物质优化分配的影响

 研究了同步叶片修剪对温室番茄品种‘Capita’干物质优化分配的影响。结果表明, 在每穗果实数修剪为6个时, 一方面会减少营养生长库强, 显著降低了叶面积指数(LA I) 和植株总干质量; 另一方面有利于干物质分配到果实, 显著提高果实累积干物质分配率, 补偿因植株总干质量降低而引起的果实干质量的降低。在合理增加植株密度时, 同步叶片修剪可以显著提高LA I与单位面积植株总干质量, 从而显著提高单位面积果实干质量。     

Effect of Pruning and Partial Disbudding on the Cropping of Comice and Beurré Hardy Pears

The effects of three intensities of pruning on fruit set, fruit bud development, cropping and vigour of intensively grown Cornice and Beurré Hardy pears were compared over a three-year period. Severe pruning, in which extension shoots were cut back to fruit buds on the two-year-old wood, greatly increased the set of fruits per 100 flower clusters and reduced vigour, in comparison with a renewal type of pruning. Severe pruning of Comice caused a relative reduction in the number of fruit buds in subsequent years, so the improvement in fruit set did not lead to an increase in crop per tree, but with Beurré Hardy fruit bud formation was unaffected and the crop per tree was increased by hard pruning. There was an improvement in yield in relation to tree size with both varieties. Pruning to fruit buds provides a means of increasing yields per acre by ‘containing’ pear trees at close spacings without reducing the yield per tree.

Partial disbudding just before blossoming increased fruit set but not enough to offset the reduction in number of fruit buds. Supplementary pollination did not improve the yields of Comice and increased the crop of Hardy in one year only.     

Mechanical injury and occlusion: An urban,tropical perspective

Eight common tree species used for urban landscaping were examined in this study for the effect of branch pruning on the rate and extent of wound closure (occlusion) and internal discolouration in the stem. Rate of wound closure when branches were removed with stem or branch of origin (flush cut pruning) and cuts made away from the branch collar (natural target pruning) were compared on all species over a 3-year period. Understanding the effects of pruning will benefit urban foresters in tree selection and potentially prevent downstream challenges associated with mechanical injury. The findings for all eight species supported the recommended guidelines of retaining the branch collar during pruning which has shown to facilitate effective wound closure. The exposed wood diameter (exposed) for all species were significantly reduced after the second growing season for injuries derived through natural target pruning but for the same period, injuries derived through flush cut pruning, only six species showed significant reductions in exposed wood diameter. Two other species (Mimusops elengi and Lagerstroemia speciosa) were observed to have no further reduction in exposed wood following the first growing season. Both wound inducing techniques (flush cut pruning and natural target pruning) resulted in no significant change in healing tissue production following the second growing season. Correlation analysis showed a strong positive relationship (r = 0.8–0.9) between the width of the wound and the length of discolouration in the stem, suggesting that smaller cuts were better suited to avoid extensive wound induced discolouration. This finding was further reinforced through visual observations of numerous pruning wounds of all eight species which showed that smaller cuts were better able to close over as opposed to larger wounds.     

Growth in horizontal apple shoots: Effects of stem orientation and bud position

In horizontal apple stems extension shoots were usually produced only from buds on the upper side of the stem, while buds on the lower side remained dormant or grew into spurs, and the same tendency was shown in inclined stems bent so that the “upper” and “under” sides became reversed.

On horizontal stems lateral shoots showed a gradient of vigour, the longest shoots being produced by proximal buds. Xylem of horizontal branches was epitrophic. These responses appear to be due to effects of gravity on the distribution of endogenous growth regulating factors within stems. In trees grown horizontally and rotated, shoots and spurs grew from all sides of the stem and xylem developed concentrically.

In studies of lateral shoots of partly disbudded horizontal stems, including cincturing treatments, it was found that the vigour of basal lateral shoots was a function of bud position in relation to the apex rather than in relation to the roots.

A model for lateral shoot growth in horizontal branches is proposed, in which shoot vigour is related to the position of buds along a postulated inhibitory gradient.     

修剪对野生杜鹃开花的影响

研究了不同修剪方法对野生杜鹃小年开花和枝条生长之间的影响.结果表明:花芽数量和开花数量,短截、摘花和轻回缩与对照存在极显著差异;枝条生长量,摘花、短截、轻回缩、中回缩和重回缩与对照存在极显著差异;摘花和短截既有利于野生杜鹃枝条生长量的增加,还能有效促进花芽分化和开花,花芽数量分别达64.6个/m2和72.8个/m2,开花数量分别达60.8朵/m2和68.5朵/m2.     

设施促早栽培下耐弱光能力不同的葡萄品种冬芽的花芽分化

为解决设施葡萄促早栽培的“隔年结果”问题,以4年生‘贝达’嫁接的不耐弱光的‘夏黑’和耐弱光的‘京蜜’为试材,通过石蜡切片法观察新梢2 ~ 7节各节位冬芽的花芽分化状况,绘制各节位冬芽群体的花芽分化进程图,研究设施促早栽培条件下耐弱光能力不同的葡萄品种冬芽的花芽分化规律。结果表明：（1）花序主轴的出现是成花起始的标志。（2）冬芽雏梢发育到含有两个叶原基至始原始体开始形成这一阶段是诱导设施葡萄成花的关键时期（生理分化期）,始原始体分化期和始原始体分裂成二分枝之后是设施葡萄成花调节的两个关键时期。（3）始原始体出现之后,冬芽雏梢生长点和始原始体发育同步是成花良好的保证,冬芽雏梢生长点营养生长过旺是抑制成花,造成“隔年结果”的重要原因。（4）‘京蜜’葡萄对设施促早栽培环境具有极佳的适应性,新梢各节位冬芽花芽分化的各阶段持续时间短且重叠阶段少,均具有良好成花能力,节位优势不明显,花芽分化从新梢基部冬芽向上依次进行,高节位冬芽花芽分化稍迟,但速度较快;冬剪采取中短梢修剪即可实现连年丰产;‘夏黑’葡萄对设施促早栽培环境的适应性差,新梢各节位冬芽花芽分化的各阶段持续时间长且多阶段相互重叠,虽然从新梢基部向上成花数量逐渐增加,成花质量逐渐改善,但不能满足生产要求,存在严重的隔年结果现象,必须采取更新修剪等相应措施方能实现连年丰产。     

Root and shoot growth of newly-transplanted apple trees as affected by rootstock cultivar,defoliation and time after transplanting

Summary

An experiment with Malus demonstrated that a large proportion of the transplanted root system was lost through death and decomposition soon after transplanting in the open ground. Mortality of the roots was not influenced by the rootstock cultivars or by defoliation but increased significantly with time. In the first month, shoots of maiden trees of Malus transplanted in June when in-leaf grew, but roots did not. Subsequently, most of the new roots on the rootstock M.9 regenerated from the rootstock stem, whereas with MM.106 the old coarse roots (>2.0 mm diameter) initially present at planting were most important. Root growth occurred in concert with shoot growth such that a functional balance was maintained as shown by the existence of a constant root length:leaf area ratio over a large part of the growing season. Following transplanting, the trees appear to re-establish their optimal ‘functional’ ratio by way of a co-ordinating pattern of growth tending to correct any disturbance to the ratio resulting from transplanting. Defoliation in the early establishment phase caused only a temporary initial reduction in the root growth, but reduced all the shoot growth variables measured and increased the root length:leaf area ratio throughout the growing season.     

Pruning Trials With Worcester Pearmain Apple

Three pruning treatments were compared on Worcester Pearmain on M.IV rootstock, viz.: open-centre tree, established-spur pruned; delayed open-centre tree, established-spur pruned; regulated pruned tree. In the fifteenth year secondary treatments were begun, the trees being pruned either annually or in alternate years, with and without fruit thinning by hand. The trees were grubbed after 21 years and scion weights were obtained.

There were no important differences in growth and cropping between open-centre and delayed open-centre trees. Regulated trees had an 11% smaller area of branch spread than established-spur pruned trees at 21 years. At 15 years there was no significant difference between treatments in total weight of prunings, but three times as much old wood as new had been removed from regulated trees compared with two and a half times as much new wood as old from established-spur pruned trees. During a 6-year period, the same weight of wood was removed from alternate-year pruned trees as from those pruned annually.

During the first 10 years regulated trees yielded twice as much fruit as did established-spur pruned ones, and 49% more during the second 10-year period. In many years, in the absence of fruit thinning, regulated trees bore smaller fruits than did established-spur pruned trees. Regulated trees had more red colour on the fruits than established-spur pruned trees, and alternate-year pruning, whether regulated or established-spur, gave more red colour on the fruits than did annual pruning, especially in seasons following no pruning. Alternate-year pruning had no harmful effect upon fruit size. Fruit thinning had no important effect upon red colour but it increased the percentage crop weight in the larger size grades, especially on established-spur pruned trees. The regulated method is well suited to the growth habit of Worcester provided that the fruit is thinned by hand or chemical spray in years of heavy setting.

The relative ratios between total crop : scion weight and crop 15–21 years : scion weight, were similar; scion weights were twice as heavy as weights of prunings.     

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.     

不同整枝方式对杂交番茄制种产量的影响

研究了不同整枝方式对杂交番茄生长的影响,结果表明,采用三秆整枝的植株在茎粗、株高、主茎叶片数、植株开展度等指标上均优于其他处理,其植株的种子产量最高,可达35.6 kg/667 m2,各处理对杂交番茄种子产量的影响顺序为:三秆整枝(A3)双秆整枝(A2)四秆整枝(A4)单秆整枝(A1)。     

Influence of slip size,deslipping and decrowning on the ‘Sugarloaf’ pineapple

Definitions: Crown = the short stem and leaves growing from the apex of the fruit. Slip = leafy branch, attached below the fruit, developed from axillary bud on the peduncle. Happa = branch arising from axillary bud at the point of junction of peduncle and stem.Large-slip plants of ‘Sugarloaf’ pineapple (Ananas comosus) (L.) Merr.) were more vigorous than small-slip plants initially; however, plants from smaller slips caught up in size within a year after planting. Large-slip and medium-slip plants produced more slips and happas than small-slip plants. Smaller slips produced heavier and larger crowns, delayed both flowering and fruit maturity, reduced fruit size and yield, and recorded a higher incidence of sunburn. Slip size did not influence sucker development, peduncle size, and % TSS, % acidity and TSS/acidity ratio of the fruit.Deslipping, and decrowning and deslipping together produced significantly more suckers than control and decrowning-treatments. Deslipping-, and decrowning and deslipping together produced the maximum fruit weight and yield, whilst deslipping produced the longest fruits. Sunburn was greatest on decrowned and deslipped fruits, followed by deslipped fruits and then by control and decrowned fruits. Pruning did not influence happa production, peduncle size, fruit maturity, and % TSS, % acidity and TSS/acidity ratio of the fruit.No significant interaction between slip size and pruning was found.     

Depressing Effects of Virus Infection on Adventitious Root Production in Apple Hardwood Cuttings

Adventitious rooting in dormant hardwood cuttings of MM. 106 apple rootstock was depressed by latent infection with five viruses, viz. rubbery wood, stem pitting, epinasty and decline, chlorotic leaf spot and platycarpa scaly bark viruses.

Both the number of rooted cuttings and the number of roots per rooted cutting were reduced, and fewer unrooted cuttings remained alive, thus representing a further potential loss.

The production of shoots suitable for use as cuttings was decreased from infected hedges, as was the ability of cuttings subsequently to become established and grow in the nursery.     

整枝对西瓜生长和结果的影响

整枝有调节西瓜植株生长势、提高叶片素质、促进坐果、增大果形等效应，但在一定程度上有减少雌花数目和结果数，降低产量等副作用；整枝应与适当密植结合起来以弥补其负面效应。在生产中，①早熟栽培可增加种植密度、减少蔓数，以增加果数，提高早期产量；②露地栽培则可减少种植株数，增加蔓数，以提高叶面积，增大果形，增加产量。③主蔓的去留与品种有关，生长势弱的品种主蔓应予保留，长势强的品种则宜摘除主蔓，利用侧蔓结果