Effect of exogenous application of free polyamines on physiological disorders and yield of ‘Kaleh-Ghoochi’ pistachio shoots (Pistacia vera L.)

Pistachio trees exhibit some physiological disorders such as abscission of inflorescence buds, fruit abscission, the production of blank, non-split, early-split and deformed nuts. Since the occurrence of these disorders is closely related to the yield, the effect of free polyamine treatments on these disorders and the yield was investigated in two consecutive years (“on” and “off” years). Free polyamine treatments were applied one week before and also two weeks after full bloom. Results showed that Spermine (Spm), unlike Putrescine (Put), decreased the physiological disorders of pistachio and also increased the yield. Free polyamine treatments did not affect the percentage of early-split nuts. Spermidine (Spd) decreased the percentage of both fruit abscission and deformed nuts but did not affect the yield. In both the “on” and “off” years the effect of Spm and Spd was greatly dependent on both the time of application and the concentrations used. Results of free polyamine analysis showed that exogenous application of these compounds, especially two weeks after full bloom, increased the free polyamine contents of shoots in both “on” and “off” years confirming the absorption of free polyamines via spray application in pistachio crop. Exogenous application of Spm two weeks after full bloom decreased the abscission of inflorescence buds in “on” year supporting the idea that free polyamines could trigger the abscission process of inflorescence buds. Since Spm decreased the percentage of blank, non-split and deformed nuts, it seems that Spm dominantly plays a key role in the growth and development of pistachio nuts.     

Potential of ethephon,NAA, NAD and urea for thinning pistachio fruitlets

Alternate bearing, the occurrence of high yield ‘on’ year followed by low yield ‘off’ year, is striking in pistachio (Pistacia vera L.). Floral buds of pistachio are formed a year before bloom, but abscise during the years with heavy crop (‘on’ year). Abscission of floral buds is due to competition between growing seeds on 1-year-old shoots and developing buds on current season growth. We studied the effects of chemical fruit thinning on alternate bearing and nut characteristics in a commercial orchard of ‘Owhadi’ pistachio cultivar during 2003–2004 in Rafsanjan, Iran. In both years, ethephon (100 and 200 mg l⁻¹), naphthaleneacetic acid (NAA) (125 and 250 mg l⁻¹) and urea (2.5 and 5%) were applied to the branch units of each individual ‘on’-year trees. The results showed that ethephon at both concentrations significantly increased fruit thinning and floral bud retention for the subsequent year. Other treatments also increased fruit thinning and floral bud retention but were inferior to ethephon.     

The effect of rootstock shoot growth on the level of bud-grafting success in apple

Poor stands of ‘Queen Cox’ apple bud-grafted in summer onto M.9 rootstock were shown to be due to the scion bud not growing, or growing too late to produce a worthwhile ‘maiden’ tree, despite virtually all scion graft-chips forming unions with the rootstock. This problem was caused by raising the budding height to 30 cm above ground, as a method of increasing the height of lateral branches. The key element in higher budding which depressed subsequent scion bud growth was the complete removal of all rootstock shoots to a height of 35 cm to give a traditional ‘clean leg’ during the budding year. Removing rootstock shoots only at the budding position gave good stands of high quality trees. This appears to be a general effect, with the benefits of retaining rootstock shoots applying also to Malus tschonoskii when budded at 30 cm on M.9 rootstock. For both ‘Queen Cox’ and M. tschonoskii, failure of scion buds to grow vigorously often resulted in the development of ‘papery bark canker’ on the M.9 rootstock. The main benefit of root- stock shoots retained in the budding year was to ensure that scion buds grew early in the following ‘maiden’ year, whereas allowing these and new rootstock shoots to remain for the first two months of ‘maiden’ growth reduced the number of secondary scion buds which developed, and raised the height of laterals by delaying their emergence.     

单株留芽量及结果母枝剪留长度对猕猴桃结果性能的影响

对栽植株行距3m×4m的美味猕猴桃秦美品种连续进行了3年试验,单株分别剪留250、300、350、400个芽处理后,平均单株新梢数、叶面积指数、落叶率与留芽数量呈正相关,叶幕下层的光强度、净光合率与留芽数量呈负相关;单株果枝数、果实数及单位面积产量均以留400芽处理最高,但平均单果重最小,88g以上的优质果产量最低。综合评价以单株剪留350个有效芽的效果最佳,优级果产量达到2102.7kg/666.7m2。结果母枝分别剪留7、12、17个有效芽处理后,平均每母枝的结果枝数、果实数、产量与留芽数量呈正相关,均以17芽处理最高,分别达到9.5个、30.4个和3.09kg,各处理间的单果重差异不显著。     

Brassinolides have a small effect on vegetative growth,and increase reproductive growth of pistachio trees Cv. Owhadi

The effects of different applications of 24-epi-brassinolideon the physiology and yield of ‘Owhadi’ pistachio trees was investigated in Iran over an off and on year. Plants were treated by 24-epi-brassinolide at 0, 0.25, 0.5, 0.75 and 1mgl^?1at green tip and tight cluster of bud stage. Brassinolide decreased the incidence nut physiological disorders and increased yield. The sprays decreased the incidence of inflorescence bud abscission, fruit abscission, misshapen nuts, blank, early splitting and indehisced shell compared with the controls. In both on and off years, the effect of brassinolide was dependent on the time of application and concentration used. Application of this compound, especially at tight cluster stage of buds, increased indehisced shell and yield in both on and off years. Brassinolides appear to play a key role in the growth and development of pistachio.     

杨桃新梢花芽分化及其碳水化合物含量的变化

 以6年生盆栽甜杨桃为材料，观察了新梢上各节位芽的分化情况，比较了新梢上不同节位的碳水化合物含量。结果表明：当第2节位开始“露红”（肉眼可辨红色的花芽）时，新梢上各节位上的芽（顶芽除外）基本上进入形态分化阶段。第3和第4节位“露红”的枝条，韧皮部和木质部可溶性糖含量比第1位和第2位“露红”的枝条高。徒长枝第1节位的可溶性糖和淀粉含量都较高，第3、第5节位的含量与第1或第2节位“露红”的成花枝上相应节位的含量相当。本研究结果表明，杨桃新梢上的芽在进行形态分化的过程中，枝条仍在积累碳水化合物。     

Growth and regeneration of plantlets in callus cultures of pineapple

Callus cultures were established from the basal region of in vitro-obtained shoot buds on MS medium supplemented with CH + CW + NAA. Such callus cultures, when grown on MS medium devoid of any growth regulators, regenerated shoot buds and optimum regeneration was obtained on MS + CW (5% v/v) medium. Addition of BA did not enhance shoot bud regeneration, but two variants (albino types) were observed among the BA-induced regenerants. The callus-regenerated shoot buds produced multiple shoots when transferred to MS + NAA + IBA + K medium. The plantlets were induced to root on a modified White's medium + NAA + IBA and subsequently transferred to soil.     

梨不同树形对光效能及产量品质的影响

 针对乔砧老梨园高接换优后因树形不同产生的效益差距问题,通过对4种高接后不同树形乔砧梨园的枝量、冠层透光率、光和参数、叶片养分、产量和品质等相关数据进行了连续两年的调查研究,筛选并确定经济效益较高的适宜树形。研究结果表明：4种树形在总枝量、短枝量及短枝/总枝量基本均衡的前提下,树冠内不同部位的透光率、有效光辐射和叶片的净光合速率、鲜样质量、养分含量均有显著差别,进而导致不同树形间果实产量和品质的差异。综合分析认为,乔砧大冠梨园改造转形宜选单层开心形,而中小冠梨树高接换优宜采用细纺锤形。     

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。     

Variability in the components of yield of black currant cultivars

Examining the components of yield of black currant cultivars in 2 successive years indicated that the number of flowers per raceme, racemes per flower bud, and mean potential berry weight, although variable between cultivars, tended to vary little within any cultivar. These components combined gave a potential berry weight per bud which appeared to be relatively stable, and may be a genetic characteristic.Year-to-year variation in yield of single cultivars was closely correlated with changes in the number of fruiting buds per bush (the product of number of shoots and fruit buds per shoot). These components are determined at different times in the year before harvest and may indicate critical phases in development of the crop.In each year, all cultivars produced roughly the same proportion of their potential crop as actual crop, although the proportion was different in the 2 years. Thus the differences between cultivars in crops harvested were related to differences in crop potential developed in the pre-fruiting year, which are considered to be due to quantitative genetic differences in potential yields per bud and differences in response to conditions affecting fruit bud formation.     

Multiple shoot regeneration in seed-derived immature leaflet explants of peanut (Arachis hypogaea L.)

A protocol was developed for organogenesis from immature leaflet explants derived from mature seeds of peanut. Immature leaflets pre-incubated on MS medium supplemented with 13.32 μM BAP + 4.95 μM NAA for 7 days, turned green and enlarged. The enlarged green leaflets produced multiple shoot buds after 1–2 cycles of sub-culture on MS medium supplemented with 13.32 μM BAP. Three cycles of shoot buds on the elongation medium (13.32 μM BAP) produced 6.17 ± 0.47 elongated shoots per explant. The shoot bud formation was genotype independent. All elongated shoots rooted on the medium containing 4.95 μM NAA. The complete protocol gave efficient (>81%) direct organogenesis, leading to the development of plantlets within 4 months.     

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.     

Effects of pruning intensity on the biochemical status of shoot buds in three mango (Mangifera indica L.) cultivars planted at high density

Summary

Mango (Mangifera indica L.) trees grown at high density show a decline in flowering and fruiting after good fruiting years as a result of various factors. Annual pruning can restore production and productivity in such trees. Chlorophyll, total sugars (TS), total phenolics (TP), and proline contents as well as polyphenol oxidase (PPO) activities, were measured in the 2005–2006 and 2006–2007 seasons in shoot buds with a few leaves in three mango cultivars (‘Amrapali’, ‘Mallika’, and ‘Dashehari’). Trees were grown at high density in an orchard and the aforesaid parameters were measured 1 month after different degrees of pruning (Stage I) and after subsequent fruit bud differentiation (FBD; Stage II). Severely-pruned mango trees had the highest contents of chlorophyll a, while chlorophyll b and total chlorophyll contents were found to be highest in moderately-pruned trees. Lightly-pruned trees had the highest contents of reducing sugars (RS), whereas TS contents were highest in severely-pruned trees. The contents of RS and TS increased in shoot buds during the FBD stage. A moderate intensity of pruning significantly increased TP contents, while the lowest TP contents were recorded in non-pruned trees. ‘Off’-year shoots had higher TP contents than ‘on’-year shoots. Irrespective of pruning intensity, shoot buds of ‘Mallika’ trees had the highest PPO activities, with lower levels in ‘Amrapali’ and ‘Dashehari’ shoot buds. PPO activities were reduced at the FBD stage in ‘on’-year shoots. Severely-pruned trees had the highest PPO activities, while the lowest PPO activities were recorded in lightly-pruned trees. Shoot bud proline contents were found to be highest in non-pruned trees, and decreased with increasing pruning intensity. Thus moderate pruning can be adopted in high density orchards to obtain sustainable production with improved maintenance of canopy architecture.     

‘四季桂’不同季节的花芽分化与发育比较

利用显微解剖和石蜡切片技术,对四季桂品种群中‘四季桂’(Osmanthus fragrans‘Sijigui’)不同季节的花芽分化及开花特性进行研究。‘四季桂’一年成花3次,分别于3月初、6月上旬和10月底开始花芽分化,4月下旬、8月底和11月底完成,分别历时约2个月、2个半月和1个月。6月开始的花芽分化和开花过程与秋桂品种群基本相似,分化后需要低温才能开花,最终形成聚伞花序,无总梗,花粉发育正常。而10月底分化的花芽在完成分化后随即开花,形成的花序有总梗,且有伸长与未伸长之分,长度分别为(0.80±0.11)cm和(3.50±0.71)cm。3月分化的花芽与新梢同时生长发育,分化完成后随即开花。春季和冬季的两次分化形成的均是圆锥状花序,具总梗,花粉均败育。结果表明‘四季桂’自身存在着不同的成花机制。     

Micropropagation of Capsicum frutescens L. using axillary shoot explants

A novel micropropagation protocol was established for Capsicum frutescens L. cv. ‘Uchithi’, a pungent chilli cultivar, through induction of axillary shoot proliferation of in vitro raised plantlets by decapitation and using the axillary shoots as explants for multiple shoot bud induction. About 2–6 axillary shoots were induced within 2 weeks when 4-week-old in vitro raised plantlets were decapitated. The axillary shoot-tip explants produced multiple shoot buds when cultured on Murashige and Skoog's (MS) medium containing 8.8–44.4 μM 6-benzylaminopurine (BAP) or 9.3–46.7 μM kinetin alone or 8.8–44.4 μM BAP with 4.6 μM kinetin or 5.7 and 28.5 μM indole-3-acetic acid (IAA). Maximum number of shoots (5.6) were induced on medium containing 22.2 μM BAP in combination with 4.65 μM kinetin. The separated shoots rooted and elongated on medium containing 2.8 μM IAA or 2.4–4.9 μM indole-3-butyric acid (IBA). Rooted plantlets were successfully established in the soil. Efficient mass multiplication of this important food crop was achieved.     

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.     

Vegetative and yield component characteristics of micropropagated muscadine grape (Vitis rotundifolia Michx.)

SUMMARY

Evaluations were made of the field performance of micropropagated (tissue cultured axillary buds) versus conventionally rooted softwood cuttings of muscadine grape, Vitis rotundifolia Michx. Trunk cross-sectional area did not differ between treatments during three years of field evaluation following planting. There were no differences in leaf area and dry weight or shoot number in the two propagation types; leaf morphology was normal with no apparent juvenile characteristics. Yield components including flower number per shoot and inflorescence, fruit number, total fruit weight and yield efficiency were greater in micropropagated plants during the second year, the first year of cropping; differences diminished and yield components were not different in year three. Performance of tissue cultured plants was therefore as good as, or surpassed, conventionally propagated plants during early vine establishment.     

Flowering of tomato in vivo and in vitro in relation to the original position of the axillary bud on the main axis

In vitro cultured tomato seedlings were micropropagated using the single-node method. By periodically subculturing single nodes and shoot tips in vitro, tomato progeny were obtained that arose from axillary buds (nodes) 1 (base) to 9 (top). Rooted shoots were transferred periodically to soil and were grown further in a greenhouse to observe flowering. The number of leaves preceding the first inflorescence in the various groups of plants was not influenced by the original position of the axillary buds on the main stem. Similar results were obtained in decapitation experiments in vivo. These results indicate that axillary buds on the main stem of tomato plants do not differ in their flowering behaviour.     

The effect of sucrose on the expression of the VvTFL1 and VFL genes during flower development in the “Xiangfei” grapevine

VFL and VvTFL1 genes expression patterns and the effects of sucrose on the expression of VFL and VvTFL1 genes in different organs of the “Xiangfei” grapevine (Vitis vinifera L.) were investigated. VvTFL1 gene expression was detected in the meristem of the apical bud and lateral bud, but was not detected during inflorescence differentiation and flower organ development. After sucrose treatment, VvTFL1 gene expression increased in the apical bud, but decreased in the lateral bud. These results suggested that the VvTFL1 gene might be mainly involved in the apical growth process of shoots, and exogenous sucrose had an effect on the VvTFL1 gene by increasing shoot apical meristem initiation of apical buds. The VFL gene was expressed primarily during inflorescence differentiation and early flower organ development, but it gradually reduced in later flower development. After sucrose treatment, VFL gene expression increased in the inflorescence and small or middle flower, but a little change was seen in the large flower. These results suggested that the VFL gene plays important roles in the initiation of inflorescence meristems and the morphological formation of flower organs. Exogenous sucrose had an effect on VFL gene expression at the early stage of flower development.