Comparison of Four Methods Calculating the Seasonal Pattern of Plant Growth Efficiency of a Kiwifruit Berry

Four methods of determining the substrate requirements for synthesisof a kiwifruit [Actinidia deliciosa (A. Chev.) C. F. Liang etA. R. Ferguson var. deliciosa cv. Hayward] berry were comparedusing data derived from common kiwifruit berry samples collectedfrom anthesis to fruit maturity. The four methods were basedon fruit proximal analysis, elemental analysis, heats of combustion,or tissue carbon content. All methods gave similar patternsof seasonal costs and values of final cost to the plant (mean1.21 g glucose g^–1 season^–1) but there was lessagreement for growth respiration (mean 0.147 g glucose g^–1season^–1). This is the first time that a continuous recordof growth cost over the course of development has been presented,and the trends in seasonal cost reflect the uptake into andsynthesis of the different biochemical constituents in the fruit.The differences between the results of each method reflect theunderlying assumptions used in their development. It appearsfrom this work that the method of McDermitt and Loomis (1981),utilizing elemental analyses, is most preferred. Actinidia deliciosa (A. Chev.) C. F. Liang et A. R. Ferguson var deliciosa cv Haywood, kiwifruit, true growth yield, plant growth efficiency, production value, glucose value, bioenergetic cost     

Sensitivity of Floral Shoot Growth, Fruit Set and Early Fruit Size inActinidia deliciosato Local Carbon Supply

The sensitivity of pre-anthesis shoot growth, fruit set andearly fruit size in kiwifruit [Actinidia deliciosa(A. Chev.)C. F. Liang et A. R. Ferguson] to cane girdling and defoliationtreatments was tested, and the results discussed in terms ofshoot carbon balance. The nature and degree of responses obtainedwas dependent on the time of application. When treatments wereapplied soon after budbreak, defoliation initially reduced growth,whereas increasingly severe girdling treatments induced responsesprogressing from stimulation to severe impairment of growthand photosynthetic capability. Similar treatments imposed laterin shoot development produced qualitatively different results.The development of floral tissues on the shoot is shown to besensitive to shoot carbon status during a period close to anthesis,and the significance of this result in relation to fruit heterogeneityat maturity is discussed.Copyright 1998 Annals of Botany Company Actinidia deliciosa, kiwifruit, shoot growth, fruit variability, fruit set, reserves.     

Cell Wall Autolysis During Kiwifruit Development

Cell walls prepared from developing kiwifruits showed autolyticactivity. The proteins extracted from active walls were alsoable to release carbohydrates from inactive cell walls. Analysisof the sugars released, using both procedures, showed that uronicacids were the major component, especially during the firsthours of incubation, although neutral sugars such as glucoseand galactose were also present. Most of the carbohydrates autolyticallyreleased from the cell wall eluted in the void volume on a BioGel P2 column. However, carbohydrates released from inactivecell walls by the protein extract mostly eluted in the monosaccharideuronic acid and glucose peaks. The autolytic activity of isolatedcell walls, as well as the glycosylhydrolase activity of theproteins extracted from the cell walls, showed important changesduring fruit development. The differences between autolyticactivity and the glycosylhydrolase activity against the cellwall suggest that the glycosylhydrolases ‘in muro’are subjected to some regulatory mechanism which disappearswith their extraction. Finally, the role of glycosylhydrolases,such as polygalacturonases and galactosidases, in relation tocell wall changes in fruits, is discussed.Copyright 1998 Annalsof Botany Company Actinidia deliciosa; autolysis; cell wall enzymes; fruit growth; glycosylhydrolases; kiwifruit.     

Estimating the Bioenergetic Cost of a Developing Kiwifruit Berry and its Growth and Maintenance Respiration Components

A response surface was developed by regression analysis to quantifythe seasonal respiratory losses by a kiwifruit [Actinidia deliciosa(A. Chev.) C. F. Liang et A. R. Ferguson var. deliciosa cv.Hayward] berry growing in Fresno, CA. The equation of the surfacewas LNRESP = 1·622 + 0·0697 x TEMP –0·0472x DAY + 0·000165 x DAYSQ, where LNRESP is the naturallogarithm of the respiration rate (nmol CO₂ g d. wt^–1s^–1), TEMP is fruit temperature (°C), DAY is the numberof days after flowering, and DAYSQ is the square of the numberof days after flowering. Respiratory losses for a fruit witha final dry mass of 18·5 g were calculated to be 5·57and 5·92 g glucose per fruit per season in 1985 and 1986,respectively. Maintenance respiration was estimated to be 2·84and 3·19 g glucose per fruit per season for 1985 and1986, respectively. The total calculated bioenergetic cost ofkiwifruit berry growth and respiration was 25·25 and25·60 g glucose per fruit per season for 1985 and 1986,respectively. Respiratory losses, expressed as a proportionof the total carbohydrate required for fruit growth, were significant(mean 22·6%). The cost of fruit growth was estimatedto be very similar for two cooler sites (Davis and Watsonville)but estimates of maintenance respiration based on Fresno fruitrespiration data were unrealistically low for the Watsonvillesite. Actinidia deliciosa (A. Chev.) C. F. Liang et A. R. Ferguson var. deliciosa cv. Hayward, kiwifruit, growth respiration, maintenance respiration, bioenergetic costs, model     

Effects of Water Stress on Fruit Quality Attributes of Kiwifruit

Four-year-old kiwifruit vines (Actinidia deliciosa(A. Chev.)C. F. Liang et A. R. Ferguson var.deliciosacv. Hayward) werestudied to determine response of the plant and effects on fruitquality when irrigation water was withheld either early or latein the growing season. The greatest effect on fruit growth occurredwhen water was withheld early in the season. Harvest weightof fruit from early-stressed vines was approx. 25% less thanthe weight of fruit on control vines. Early season water stressresulted in a transient increase in concentrations of solublecarbohydrates in both leaves and fruit. This was accompaniedby a reduction in stomatal conductance of the leaves. Starchlevels in leaves but not fruit were reduced by both stress treatments.Concentrations of sucrose at harvest in fruit from vines stressedlate in the season were markedly higher than in other fruit,and softness of the fruit was unaffected. These differenceswere maintained through the 12 weeks in cool storage after harvest.Withholding irrigation water to kiwifruit vines late in theseason may prove a useful management tool to manipulate somequality attributes of the fruit.Copyright 1998 Annals of BotanyCompany Kiwifruit;Actinidia deliciosa; water stress; fruit quality; soluble solids.     

Growth and Compositional Changes in Kiwifruit Berries from Three Californian Locations

Kiwifruit [Actinidia deliciosa (A. Chev.) C. F. Liang et A.R. Ferguson var. deliciosa cv. Hayward] berries were sampledfrom three Californian locations, two sites in the central valley(near Davis and Fresno), the other on the coast (near Watsonville).Samples were analyzed for nitrogen, lipid, starch, soluble sugars,organic acids and ash, at regular intervals from flowering untilharvest. The results of the analyses of the fruit from the twocentral valley sites were similar, but markedly different fromthose from the cooler coastal site Sugar/acid ratios were consistentlyhigher in fruit from the coast than the central valley. Thismay prove a useful refinement to the current maturity index. Actinidia deliciosa (A. Chev.) C. F. Liang et A. R. Ferguson var. deliciosa cv. Haywood, kiwifruit, fruit growth, fruit composition, seasonal changes     

Uptake of 15N by Kiwifruit Vines from Applications of Nitrogen Fertilizer Prior to Budbreak

Mature field-grown kiwifruit vines (Actinidia deliciosa var.deliciosa cv. Hayward) were fertilized with ¹⁵N-labelled fertilizer(ammonium sulphate, 10 atom % ¹⁵N, 50 kgN ha^-1) to investigatethe timing of uptake of fertilizer nitrogen (N) and its availabilityfor new season's growth. Treatments were applied on four occasions,representing 2, 6, 10 and 14 weeks prior to budbreak. Samplesof root, stem, cordon, fruiting cane, vacuum-extracted xylemsap, and new season's growth were collected at fortnightly intervalfrom early winter until 2 months after budbreak. Two weeks after application of each treatment, ¹⁵N equivalentto an average of 7% of the applied label was recovered in rootmaterial. Although label was taken up by roots, there was nomovement of ¹⁵N within the plant until about 1 month prior tobudbreak when it was measured in the stem and cordon. Fertilizernitrogen was not detected at the distal end of fruiting canes,and in new season's growth until 3-4 weeks after budbreak. Beforebudbreak, all nitrogen in the xylem sap was in amino forms.Nitrate appeared 4 weeks after budbreak, and although more enrichedwith ¹⁵N than the amino nitrogen, accounted for only 19% ofthe label. Eight weeks after budbreak, nitrate nitrogen accountedfor 57% of the label. There were no major treatment effects of ¹⁵N on vines in eitherspring or at harvest, although enrichments in fruit and leavesfrom the earliest treatment tended to be less at the end ofthe season than those from the later applications.Copyright1993, 1999 Academic Press Actinidia deliciosa, kiwifruit, nitrogen, ¹⁵N, nutrient uptake     

Pollen Development in Actinidia deliciosa var. deliciosa: Histochemistry of the Microspore Mother Cell Walls

The development of the microspore mother cell walls in Actinidiadeliciosa (kiwifruit) has been studied using light and electronmicroscopy. The microspore mother cell wall is similar, histochemically,and structurally in anthers from both functionally staminateand functionally pistillate flowers. Deposition, which beginsduring early prophase I, produces an electron-dense multilaminatedwall layer (layer a) and by the end of meiosis I a thick electron-lucentlayer (layer b) to the inside of this multilayered wall. Thereasons for histochemical differences and similarities betweenthese layers are discussed. The original primary wall persistsuntil the late uninucleate microspore stage. Layer (b), whichis probably mainly callose, dissolves at the late tetrad/earlymicrospore stage while layer (a), which probably also containsother polysaccharides, persists and dissolves concurrently withthe primary wall. Actinidia deliciosa, kiwifruit, microspore mother cell wall, callose, histochemistry, light microscopy, electron microscopy, male sterility     

Xyloglucan endotransglycosylase activity during fruit development and ripening of apple and kiwifruit

Xyloglucan endotransglycosylase (XET) activity was measured in apple (Malus domestica Borkh. cv. Braeburn) pericarp and kiwifruit (Actinidia deliciosa [A. Chev.] C. F. Liang et A. R. Ferguson var. deliciosa cv. Hayward) outer pericarp and core tissues in order to establish whether a correlation exists between the activity of the enzyme and different stages of fruit development Whereas the growth rate of kiwifruit paralleled changes in XET activity throughout fruit growth, that of apple did not. Both fruits showed the highest XET activity, on a fresh weight basis, in the first two weeks after anthesis when cell division was at its highest. XET activity then decreased sharply, but as the fruit increased in size (4–8 weeks after anthesis) there was a concomitant increase in XET activity in both fruits. In the latter stage of fruit development (16–26 weeks after anthesis) XET activity increased to peak at harvest in apple fruit. During this time there was relatively little increase in fruit size and presumably therefore minimal cell expansion. XET activity then declined as fruit softened after harvest. In core tissue from kiwifruit, XET activity increased throughout the later stages of fruit growth to harvest maturity in a similar manner to apple, but continued to increase after harvest until fruit were ripe. In contrast, XET activity in the outer pericarp of kiwifruit did not increase until ripening after harvest. In apple tissue up to 30% of the XET activity was cell wall bound and could not be solubilised, even in buffer containing 2 M NaCl. The results implicate XET in cell wall assembly during cell division and expansion early in apple and kiwifruit growth. However, the disparity between apple and kiwifruit with respect to XET activity late in fruit development and ripening and the different affinities of the enzyme for the cell wall in each fruit, suggest that XET has several roles in plant development, not all of which are related to cell wall loosening during periods of accelerated growth.     

The Acquisition and Utilization of Carbon in Early Spring by Kiwifruit Shoots

Measurements of net photosynthetic rate (at 1450µ molm^-2s^-1photosynthetically active radiation) of leaves, of leafand stem respiration, and of shoot growth of potentially-fruitinglaterals on kiwifruit (Actinidia deliciosa ) were used to estimateweekly shoot carbon balances over the first 10 weeks of shootgrowth (budburst to anthesis). Consistent differences in therate of shoot elongation, of internode expansion and of increasein basal diameter were found among shoots. Faster-growing (long)shoots acquired carbon by photosynthesis at a faster rate evenin the first few weeks after budburst, but the amount of carbonrequired to sustain this growth resulted in shoot carbon deficitswhich were approx. seven times greater than those of the slower-growing(short) shoots. It was estimated that the transition from shootcarbon deficit to carbon surplus occurred 3–4 weeks afterbudburst, irrespective of shoot growth rate. As a result ofsubsequent rapid increases in shoot photosynthetic rate, longshoots had a shoot carbon surplus of 4.4 g C week^-1in the weekbefore anthesis, approx. three times that of the short shoots.Defoliation (66%) of shoots 1 week after budburst, and subsequentremoval of later-emerging leaves to maintain the level of defoliation,had the effect of slowing shoot growth in the carbon deficitperiod, particularly for the long shoots. However, the durationof shoot expansion in the defoliated shoots was longer, resultingultimately in shoots which were longer than the control shoots.Linkages among early carbon balance dynamics of shoots, shootlength at anthesis, and fruit growth are discussed. Actinidia deliciosa ; kiwifruit; shoot growth; carbon acquisition; respiration; photosynthesis     

Estimation of the Annual Cost of Kiwifruit Vine Growth and Maintenance

Elemental analysis (for carbon, hydrogen, nitrogen and sulphur)and ash data for kiwifruit [Actinidia deliciosa (A. Chev.) C.F. Liang et A. R. Ferguson var. deliciosa cv. Hayward] stems,leaves and fine roots were used to calculate the specific costs(kg carbohydrate kg^-1 dry matter) of organ synthesis with ammoniacalnitrogen supply. Those costs ranged between 1·19 and1·35 for stems and 1·19 and 1·27 for leaves.The mean annual specific cost for fine roots was 1·17.Seasonal vine growth costs were calculated by multiplying thespecific costs by biomass data for a typical vine. Total costof synthesis was 57·2 kg carbohydrate per vine year^-1,taking fine root turnover as three times per season. Nitratenitrogen supply increased that cost by 6·6% to 61·0kg carbohydrate per vine year^-1. Fruit growth accounted forthe largest proportion of synthetic costs. Vine growth respiration(expressed in terms of carbohydrate equivalents) accounted forapproximately 11·5% of the total cost of synthesis. Maintenancerespiration was estimated to be 5·28, 8·44, 1·90,8·62 and 13·3 kg carbohydrate per organ year^-1for stems, leaves, fruit, above-ground perennial componentsand roots, respectively. Total annual cost of growth and maintenancefor a mature vine was 94·7 and 98·5 kg carbohydrateper vine year^-1 with ammoniacal and nitrate nitrogen supply,respectively. Both values are similar to an estimate of vinephotosynthesis. Maintenance respiration accounted for approximately40% of the total annual cost of vine growth, regardless of theform of nitrogen supplied. Peak carbohydrate demand was duringthe period from 60 to 160 d after budbreak.Copyright 1995, 1999Academic Press Actinidia deliciosa, kiwifruit, carbon economy, growth respiration, maintenance respiration     

Kiwifruit β-galactosidase: Isolation and activity against specific fruit cell-wall polysaccharides

A -galactosidase (EC 3.2.1.23) capable of degrading a number of fruit cell-wall polysaccharides in vitro, was isolated from ripening kiwifruit (Actinidia deliciosa [A. Chev.] C.F. Liang et A.R. Ferguson cv. Hayward). The enzyme has a molecular weight of approximately 60 kDa by gel permeation and consists of several basic isoforms. Several polypeptides were enriched during purification, with 33-, 46- and 67-kDa bands being predominant after sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The optimum activity of the enzyme against p-nitrophenyl--d-galactopyranoside was at pH 3.2, but against a galactan purified from kiwifruit cell walls, it was at pH 4.9. The enzyme was specific for galactosyl residues in the -configuration, releasing galactose from a variety of kiwifruit cell-wall polysaccharide fractions including cell wall material, Na₂CO₃-soluble pectin, high-molecular-weight galactan, xyloglucan, and galactoglucomannan. A galactosylated glucuronomannan found throughout the kiwifruit plant was also a substrate for the enzyme. The results indicate that the enzyme attacks the non-reducing end of galactose side chains, cleaving single galactose residues which may be attached to the 2, 3, 4, or 6 position of the aglycone. Activity of the enzyme in-vitro was too low to account for the total loss of galactose from the cell walls during ripening. If the -galactosidase of this study is solely responsible for the removal of galactose from the cell wall during ripening then its in-vivo activity must be much greater than that observed in-vitro.Abbreviations CWM cell wall material - SDS-PAGE sodium dodecyl sulphate-polyacrylamide gel electrophoresis We thank Bronwyn Culling and Teresa Wegrzyn for assistance and acknowledge a contribution towards the cost of the research from the New Zealand Kiwifruit Marketing Board.     

Seasonal Dynamics of Biomass and Mineral Nutrient Partitioning in Mature Kiwifruit Vines

The accumulation of dry matter plus macro- and micronutnentsby various components of 6-year-old, field-grown kiwifruit vines(Actinidia deliciosa var deliciosa cv Hayward) was recordedover one season Twenty vines were harvested periodically throughoutthe year and separated into perennial components (roots <20 mm diameter, structural roots, stump, stem, cordon, one-year-oldfruiting wood) and current season's growth (non-fruiting shoots,laterals on fruiting wood, leaves and fruit) There was minimalseasonal variation (CVs < 7%) in biomass change in perennialcomponents of the vine Concentrations in these components eitherfluctuated about a constant value, or indicated a strong seasonaldependence Changes in biomass and nutnent concentrations incurrent season's growth, however, were very regular Prior tobudbreak, below-ground components contained between 48 and 81% of the total content of each element Roots < 20 mm diametercontained more total nutrient than any other perennial componentof the vine during the season, with the exception of Zn andCu, which were concentrated in the cordon There was consistentaccumulation of each nutrient from budbreak until harvest Ratesof greatest uptake occurred in the month following budbreak,or in the 3 weeks after anthesis Between dormancy and harvest,whole-vine contents increased for all nutrients Increases inFe, Mg, P, S and Zn ranged from 21 % (Zn) to 88% (Mg), and inB, Ca, Cl, Cu, K, N and Mn from 109% (Cu) to 302% (Cl) Despitethe large requirements of the current season's growth, net changesin the seasonal content of perennial components were relativelysmall Copper, Mg, P, N and Cl were the elements in which perennialreserves were utilized to the greatest extent to meet transientdeficits between nutnent demand for the current season’sgrowth, and that recently taken up from soil Generally, reserves utilized during the period of vegetativegrowth were replaced by harvest-time These observations, basedon application of a single fertiliser dressing before budbreak,suggest the vine maintains satisfactory fertility without theneed for late-season or post-harvest applications of fertiliserto supplement nutrient reserves, as occurs with some other fruitingcrops Actinidia deliciosa, kiwifruit, mineral nutrition, seasonal accumulation, whole-plant harvesting     

Spatial Analysis of the Canopy of Kiwifruit Vines as it Relates to the Physical, Chemical and Postharvest Attributes of the Fruit

The position of individual fruit on kiwifruit vines (Actinidiadeliciosa var. deliciosa) grown on a horizontal trellis (pergola)and on a T-bar trellis was determined using a theodolite. Thephysical, chemical, and postharvest attributes of the fruitwere related to their position on the vine during development. Fruit from the pergola vines were more numerous, of lesser weight,with lower concentrations of most mineral nutrients, but greaterconcentrations of soluble solids, and similar flesh firmnessafter 12 weeks of storage at 0 °C, than fruit from the T-barvines. The position on the vine accounted for most of the variationin the attributes of the fruit. Differences between fruit ona single lateral accounted for 43-56% of the variation. Variationbetween vines was relatively small (< 4% of the total variance). The heavier fruit were located at the apical ends of the laterals,while greater concentrations of soluble solids were associatedwith fruit located closer to the cordon. The larger fruit fromthe pergola vines developed from the early opening flowers.A similar relationship existed initially for the T-bar vines,but a reduction in growth of fruit from the early opening flowers8 weeks after anthesis resulted in a more even distributionof fruit size at harvest. The strongest relationship between mineral composition and postharvestattributes of the fruit was with soluble solids concentration(29-46% of the variance). The relationship with flesh firmnesswas weak (r = -0·14 to -0·32). Individual elementscould not be considered in isolation but rather in groups ofelements. Nitrogen was grouped strongly with phosphorus, sulphur,potassium, and copper, while calcium was linked with a secondgroup which included manganese and zinc. These two groups werenegatively related to one another. The greatest proportion of fruit with superior characteristicswas located in the denser parts of the canopy. Fruit with lessdesirable attributes were from the extremities of the canopywhere the leaf area index was low.Copyright 1994, 1999 AcademicPress Actinidia deliciosa, kiwifruit, fruit position, fruit quality, within-vine variation     

Shoot Axillary Bud Morphogenesis in Kiwifruit (Actinidia deliciosa)

The annual cycle of kiwifruit [Actinidia deliciosa(A. Chev.)C. F. Liang et A. R. Ferguson var.deliciosacv. Hayward] shootaxillary bud (first-order axillary bud, FOAB) morphogenesisis described. FOABs developed quickly with the majority of budscales and leaf primordia present approx. 125 d after budbreak(dab). Mature FOABs had, on average, 23.2 bud scales and leafprimordia. Most second-order axillary structures were also presentapprox. 125 dab. During the growing season, the second-orderstructures developed into second-order axillary buds (SOABs)or remained as simple, dome-shaped meristems (SDSMs). At maturity,nearly all FOABs had four SOABs and, on average, 12.4 SDSMs.Most SDSMs were fused to the subtending leaf primordia, butsome SDSMs developed so that they were ‘free’ fromthe subtending leaf primordia. Third-order axillary meristems(third-order SDSMs) were observed in the axils of most SOABs,and, on average, there were 20.6 per FOAB. Our observationson the development of second-order axillary structures are consistentwith evocation in kiwifruit occurring earlier than the generally-acceptedtime of late summer. Actinidia deliciosa; bud morphogenesis; development; flowering; evocation     

Seasonal Accumulation of Starch by Components of the Kiwifruit Vine

The accumulation of starch by various components of 6-year-oldkiwifruit vines (Actinidia deliciosa var dehciosa cv Hayward)was recorded over one season Twenty vines were harvested periodicallythroughout the year and separated into perennial components(fibrous roots, structural roots, stump, stem, cordon, laterals)and current season's growth (shoots, leaves, and fruit) The concentration of starch in the fibrous roots followed asinusoidal trend Minimum concentrations occurred 98 d afterbudbreak, while the maximum concentrations occurred 182 d laterCorresponding times in the structural roots were approximately42 d earlier In the above-ground perennial components, elevatedconcentrations of starch in the cordon, fruiting wood and barkof the stem were evident at budbreak and fruit harvest (approx220 d later) In the case of the stem, concentrations were greatestat fruit harvest Because the biomass of the perennial componentswas found to be relatively constant throughout the year, starchconcentrations and contents were directly proportional in thesetissues For current season's growth, peak concentrations and contentsin leaves and shoots were observed at fruitset and fruit harvest,respectively For fruit, starch increased continuously untilharvest Approximately 30% of the total starch content accumulated inthe perennial components by leaf abscission was lost duringwinter and early summer Quantitative losses were greatest forthe roots Regeneration of the starch pools in the perennialcomponents of the vine occurred from midseason until leaf abscissionAt the same time, approximately five times more starch was accumulatedby the current season's growth, in particular the fruit, thanby the perennial components As a result of the difference inthe rate of accumulation, the starch content of the currentseason's growth increased from less than 10% midseason to nearly60% of the total starch content of the vine by fruit harvest The results were discussed in relation to the carbon economyof the kiwifruit vine, and compared with seasonal trends instarch concentrations found for other deciduous crops Actinidia deliciosa, kiwifruit, seasonal changes, starch content, whole plant     

A Method for Analysing Plant Architecture as it Relates to Fruit Quality Using Three-dimensional Computer Graphics

A method was developed for the spatial analysis of plant architectureas it relates to the within-plant variation in the physical,chemical, and postharvest characteristics of the fruit Computergraphics were used to reconstruct the architectural frameworkand spatial arrangement of the fruit in the canopy of kiwifruitvines (Actinidia deliciosa) trained on two different supportstructures An infra-red beam theodolite was used to obtain thespatial coordinates of the vines components The data files generatedby the theodolite were in turn used with software specificallywritten for the project (MAPIT—Microcomputer Aided PlantImaging Technology) to provide a 3-dimensional reconstructionof the original vines Each fruit was colour coded so that extremesin their attributes could be easily identified and accuratelylocated in the canopy of the vine Patterns were clearly discerniblefor both the pergola and T-bar trained vines The heavier fruitwere located at the apical ends of the canes, while greatersoluble solids concentrations were associated with the smallerfruit located closer to the cordon These patterns were consistentfor all of the vines examined The use of the theodolite coupledwith the computer graphics described in this paper providesa rapid and objective means of accurately describing plant architecture Computer graphics, plant architecture, spatial analysis, theodolite, three-dimensional analysis, fruit quality, Actinidia deliciosa, kiwifruit     

Seasonal Concentrations of Non-structural Carbohydrates of Five Actinidia Species in Fruit, Leaf and Fine Root Tissue

To characterize seasonal patterns of carbohydrate concentrationsin Actinidia species from different natural habitats, leaf,fruit and fine root tissue samples from five species (A. arguta,A. deliciosa, A. chinensis, A. polygama and A. eriantha) werecollected over one season, and analysed for fructose, glucose,sucrose, myo -inositol and starch concentrations. Sucrose andstarch peaked in leaf tissue around flowering time. In fruit,hexose sugars and/or myo -inositol transiently increased earlyin development. Starch accumulated in fruit of all species,beginning sooner after anthesis in A. arguta and A. polygamathan in the other species. Sucrose accumulation coincided withonset of net starch degradation in A. arguta but was delayedin the other species. At final fruit sampling, concentrationsof glucose and fructose were greater than sucrose in all speciesexceptA. arguta . myo -Inositol concentrations constituted >10%of total sugars for most of the season in leaf and fruit tissuesof all species except A. polygama. Fine roots of A. arguta andA. polygama contained significantly more starch and sucrosefor most of the year than those of the other species. Observeddifferences in seasonal carbohydrate patterns may reflect differentnatural habitats, with A. arguta and A. polygama growing naturallyin colder climates than the other species. Transient accumulationof sugars in fruit during early stages of development has beenconsidered to act as primary osmoticum for cell expansion. However,the presence of only low sugar concentrations in A. erianthaquestions this hypothesis. Copyright 2000 Annals of Botany Company Actinidia arguta, Actinidia deliciosa, Actinidia chinensis, Actinidia eriantha,Actinidia polygama , kiwifruit, carbohydrates, fruit, leaves, fine roots, seasonal     

Papillar integrity as an indicator of stigmatic receptivity in kiwifruit (Actinidia deliciosa)

Stigmatic receptivity is a major factor limiting fruit set inkiwifruit (Actinidia deliciosa). The aim of this work was toknow what determines the cessation of stigmatic receptivityin this species. Stigmatic receptivity has been analysed inkiwifruit through the capacity of the stigma to sustain pollengermination and has been related to stigmatic development anddegeneration.The stigma of kiwifruit flowers has a papillatesurface which from anthesis is covered with an abundant exudate.Papillae are unicellular and contain a number of phenolic deposits.During the lifetime of the flower these papillae gradually loseturgidity, while stigmatic secretion increases until 5 d afteranthesis when papillae start rupturing and the papillar contentis liberated into the germination medium. Stigmatic receptivityis high at anthesis and lasts for the next 4 d. However, itdrastically decreases 5 d after anthesis and it is nil 2 d later.The pattern of stigmatic receptivity closely fits that of papillarintegrity, indicating that stigmatic receptivity relies on thisintegrity. Since papillar integrity can easily be evaluatedin stigmatic arms, this criterion can be used as a quick methodto estimate stigmatic receptivity. Key words: Actinidia deliciosa, kiwifruit, stigma, receptivity, pollen     

Influence of Irradiated Pollen on Embryo and Endosperm Development in Kiwifruit

Development of seeds following pollination with irradiated pollenwas studied inActinidia deliciosa(kiwifruit) ‘Hayward’.Pollinations were carried out using two different sources ofpollen (‘Tomuri’ and ‘Matua’) irradiatedwith gamma rays at doses of 700 and 900 Gy. Non-irradiated crosseswere used as controls. Pollen irradiation had little effectonin vitropollen germination. Irradiated pollen affected seedset and seed content, and induced the formation of parthenogeneticembryos. In comparison to the control, the embryo growth ratewas slower and the endosperm contained very low amounts of storageproducts. Seed set was significantly reduced following bothdoses of irradiation. Two types of seeds were observed: (1)seeds with endosperm only; and (2) seeds with both embryo andendosperm. The proportion of seeds containing endosperm onlywas almost ten-fold higher than those containing both embryoand endosperm. Embryo production by gamma-irradiated pollenwas genotype- and dose-dependent. The induction of parthenogenesiswas higher following gamma ray doses of 900 Gy than 700 Gy,which suggests the ‘Hertwig Effect’; the best efficiencywas obtained with ‘Tomuri’ pollen. Ploidy levelof parthenogenetic embryos was evaluated by nuclear size (area)with the use of image analysis. There was a large differencein embryo nuclei size between control and parthenogenetic embryos(mean size 90.8 and 49.1 µm², respectively). It is concludedthat parthenogenetic embryos represent trihaploids.Copyright1998 Annals of Botany Company. Actinidia deliciosa, kiwifruit, pollen irradiation, induced parthenogenesis.