The Plastids and Pigments of Fresh and Dried Chinese Gooseberries (Actinidia chinensis)

The pericarp of Chinese gooseberries is green due to the presenceof low concentrations of chlorophylls. On a f. wt basis thereis about 1.5 times more tetrapyrollic pigments (chlorophyllsand related compounds) in the outer pericarp than in the innerpericarp, whereas the carotenoid pigment values only showed1.25 times more in the outer than in the inner part of the fruit.The drying of Chinese gooseberries at 40 °C for 40 h resultedin the loss of at least half the tetrapyrollic pigments andof carotenoids. Chlorophylls a and b were converted to chlorophyllides,pheophytins and pheophorbides. Chloroplasts in the outer pericarp are clustered closely aroundthe nucleus and have a well-defined grana and inter-granal membranesystem. In the inner pericarp the chloroplasts are again clusteredaround the nucleus and there is a proliferation of inter-granalmembranes. In dried tissue the limiting membrane of chloroplastswas completely dispersed whereas some of the internal membranesremained intact. Actinidia chinensis Planch., Chinese gooseberry, Kiwi fruit, pigments, chloroplast structure     

Bud Dormancy in the Kiwi Fruit, Actinidia chinensis Planch

A study of lateral bud dormancy in Actinidia chinensis has shownthat true dormancy can be induced, especially in short daysat warm and constant temperatures This dormancy can be brokenquantitatively by chilling but temperatures as high as 10 °Care effective The dormancy appears to be due to an inhibitor(possibly ABA), apparently stored in the special bud cover aspecial structure in Kiwi fruit which may represent fused stipulesRemoval of the cover also admits oxygen and light, both of whichhave promoting effects on bud break Application of ABA enhancesdormancy (as do crude extracts tentatively identified as ABA)while GA₃ application enhances dormancy before chilling andpromotes bud break only after chilling Actinidia chinensis, Kiwi fruit, dormancy, abscissic acid, gibberellic acid, chilling     

Xylem Sap from Actinidia chinensis: Gradients in Sap Composition

In early spring, just prior to leaf break, there were substantialgradients in the concentration of many solutes in xylem sapcollected by vacuum extraction from shoots of different ages,from the branches, trunk and roots of mature Chinese gooseberryvines (Actinidia chinensis Planchon) For most nutrients therewas a progressive fall in concentration from youngest shootsdown to the roots and nitrate was the only nutrient to showa trend in the opposite direction These gradients in concentrationare probably sufficient to account for most of the changes observedin the composition of bleeding xylem sap during the first fewhours of bleeding after a branch is cut or wounded Actinidia chinensis, Chinese gooseberry, kiwifruit, xylem sap, nutrient gradients     

Some Effects of Daylength, Temperature and Exogenous Growth Regulator Application on the Growth of Actinidia chinensis Planch

The growth responses of Actinidia chinensis raised from cuttingswere compared in 8 h short days (SD) and 16 h long days (LD)at 15, 20 and 25 °C, as well as under varying day and nighttemperatures The data obtained reveal effects on stem elongation,apparent plastochrons, leaf area and shape, as well as dry matteraccumulation and water contents of different plant parts Theseinvestigations were supplemented by studies on the effects ofapplied GA₃ and ethephon Alternating day/night temperatures(thermoperiodicity) increased leaf area and d wt accumulationin LD Effects on sugar and starch contents, are described anddiscussed Unexpected effects such as very high petiole watercontents and their continuous growth, increased twisting ofthe climbing stem in SD and other findings are also reportedand discussed Actinidia chinensis, Kiwi fruit, gibberellic acid, ethephon, temperature, photoperiod, themoperiodicity     

Xylem Sap from Actinidia chinensis: Apparent Differences in Sap Composition Arising from the Method of Collection

Large differences in composition were found between xylem sapcollected from Actinidia chinensis (Chinese gooseberry or kiwifruit) as bleeding sap and sap collected by vacuum extraction.A comparison of saps collected by the two methods has littlemeaning, however, unless the position on the plant from whichsap was collected and the prior treatment of the plant are specified.Furthermore the composition of bleeding sap changes rapidlywith time, probably because of marked gradients in concentrationof individual solutes in the xylem sap from the base to thetop of the plant. Contamination of vacuum-extracted sap by cellularcontents was shown to be insignificant. Sap collected as bleeding sap and by vacuum extraction are ofsomewhat different origins. It would be difficult to predictthe composition of bleeding sap simply from a knowledge of vacuum-extractedsap: it may be similarly unwise to predict the composition ofthe transpiration stream from that of vacuum extracted sap. Actinidia chinensis, kiwi fruit, Chinese gooseberry, xylem sap, bleeding sap, vacuum-extraction     

Xylem Sap from Actinidia chinensis: seasonal Changes in Composition

Seasonal variation was followed in the content of total a-aminoacids, arginine, calcium, total carbohydrate, ß-galactosidaseactivity, magnesium, nitrate, phosphatase activity, phosphateand sulphate in vacuum-extracted xylem sap from Actinidia chinensisvar. hispida, the Chinese gooseberry or kiwifruit. There wasa marked increase in the concentration of most sap componentsjust prior to leaf emergence followed by a rapid decrease afterthe leaves had expanded. Experiments with excised extensionshoots showed that much of this spring-time increase in concentrationsof sap components was due to mobilization of nutrients withinthe shoot itself. Sap from the trunk and the older brancheschanged less in composition than did sap from the younger partsof the plant. The amplitude and direction of trends in concentrationof sap from the different parts of the plant varied with nutrientand with time. Analysis of vacuum-extracted xylem sap collectedduring periods of rapid transpiration from early summer onwardsgives a reliable indication of the composition of the transpirationstream. Actinidia chinensis, Chinese gooseberry, kiwifruit, storage reserves, xylem sap, amino acids, arginine, calcium, carbohydrate, ßgalactosidase, magnesium, nitrate, phosphatase, phosphate, potassium, sulphate     

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     

Pollen Tube Distribution in the Kiwifruit (Actinidia deliciosaA. Chev. C. F. Liang) Pistil in Relation to its Reproductive Process

High resolution light and fluorescence microscopy were usedto investigate the structural and cytochemical features of thekiwifruit(Actinidia deliciosa)pistil and to follow the pollentube pathway after pollination. The multicarpellary ovary issyncarpous only at the ovary level thus leaving 30–40free styles on top. The fusion of the longitudinally-foldedcarpels to form the syncarpous ovary forms a central parenchymatousaxis, the columella, from which the ovules radiate outwardsinto the ovary cavity. A prominent cup shaped depression onthe columella at the top end of the ovary, termed the pollentube distributor cup (PTDC) was detected. Pollen tubes fromthe stigma travel through the transmitting tract and enter thePTDC from where they are distributed towards the ovary. Evenwhen pollination is restricted to two stigmas, the PTDC seemsto ensure that the pollen tubes are evenly distributed aroundthe ovary resulting in an even distribution of seeds. This suggestedrole of the PTDC which could compensate for over and under pollinationof individual stigmatic arms is another adaptive feature whichplays a crucial role in the reproductive process of kiwifruit.The significance of this structure for pollination by insectsis discussed.Copyright 1998 Annals of Botany Company Actinidia deliciosa, kiwifruit, pollination, floral anatomy, reproductive success, pollen tube distribution.     

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     

Induced polyploidy dramatically increases the size and alters the shape of fruit in Actinidia chinensis

Background and Aims

Some otherwise promising selections of Actinidia chinensis (kiwifruit) have fruit that are too small for successful commercialization. We have therefore made the first detailed study in diploid kiwifruit of the effects of chromosome doubling induced by colchicine on fruit size, shape and crop loading.

Methods

Flow cytometric analysis of young leaves and chromosome analysis of flower buds and root tips was used to confirm the stability of induced autotetraploids. Fruit weight, size and crop load were measured in the third year after planting in the field and for three consecutive years. DNA fingerprinting was used to confirm the origin of the material.

Key Results

There was a very significant increase in fruit size in induced autotetraploids of different genotypes of A. chinensis. With the commercially important diploid cultivar ‘Hort16A’, most regenerants, Type A plants, had fruit which were much the same shape as fruit of the diploid but, at the same fruit load, were much larger and heavier. Some regenerants, Type B plants, produced fruit similar to ‘fasciated’ fruit. Fruit of the autotetraploids induced from three female red-fleshed A. chinensis selections were also 50–60 % larger than fruit of their diploid progenitors. The main increase in fruit dimensions was in their diameters. These improved fruit characteristics were stable over several seasons.

Conclusions

Chromosome doubling has been shown to increase significantly fruit size in autotetraploid A. chinensis, highlighting the considerable potential of this technique to produce new cultivars with fruit of adequate size. Other variants with differently shaped fruit were also produced but the genetic basis of this variation remains to be elucidated. Autoploids of other Actinidia species with commercial potential may also show improved fruit characteristics, opening up many new possibilities for commercial development.     

An interspecific somatic hybrid between Actinidia chinensis and Actinidia kolomikta and its chilling tolerance

Protoplasts isolated from cotyledon-derived callus of Actinidia chinensisPlanch. var. chinensis (2N=2x=58) were fused with mesophyll protoplasts of Actiniadia kolomikta(Maxim. et Rupr.) Maxim (2N=2x=58) using a PEG method. Plantlets were regenerated from the fusion product clone 11. RAPD analyses, chromosome numbers of root tip cells and fluorescence peak position of leaf nuclei confirmed that clone 11 was an interspecific somatic hybrid (2N=4x=116) between A. chinensis and A. kolomikta. The chilling tolerance of the somatic hybrid was tested with in vitro leaves at low temperatures. Based on data of leaf thickness, electroconductivity, proline levels, malondialdehyde content and activity of superoxide dismutase, dendrogram cluster analysis suggested that the interspecific somatic hybrid was similar to A. kolomikta, and might have a higher capacity of cold resistance than A. chinensis.     

High‐temperature inhibition of biosynthesis and transportation of anthocyanins results in the poor red coloration in red‐fleshed Actinidia chinensis

In plants, the role of anthocyanins trafficking in response to high temperature has been rarely studied, and therefore poorly understood. Red‐fleshed kiwifruit has stimulated the world kiwifruit industry owing to its appealing color. However, fruit in warmer climates have been found to have poor flesh coloration, and the factors responsible for this response remain elusive. Partial correlation and regression analysis confirmed that accumulative temperatures above 25°C (T25) was one of the dominant factors inhibiting anthocyanin accumulation in red‐fleshed Actinidia chinensis, ‘Hongyang’. Expression of structural genes, AcMRP and AcMYB1 in inner pericarp sampled from the two high altitudes (low temperature area), was notably higher than the low altitude (high temperature area) during fruit coloration. AcMYB1 and structural genes coordinate expression supported the MYB–bHLH (basic helix‐loop‐helix)–WD40 regulatory complex mediated downregulation of anthocyanin biosynthesis induced by high temperatures in kiwifruit. Moreover, cytological observations using the light and transmission electronic microscopy showed that there were a series of anthocyanic vacuolar inclusion (AVI)‐like structures involved in their vacuolization process and dissolution of the pigmented bodies inside cells of fruit inner pericarp. Anthocyanin transport was inhibited by high temperature via retardation of vacuolization or reduction in AIV‐like structure formation. Our findings strongly suggested that complex multimechanisms influenced the effects of high temperature on red‐fleshed kiwifruit coloration.     

NMR and DSC Water Study During Osmotic Dehydration of Actinidia deliciosa and Actinidia chinensis Kiwifruit

This study investigated mass transfer and water state changes promoted by osmotic dehydration on two kiwifruit species, Actinidia deliciosa and Actinidia chinensis. Osmotic treatment was performed in a 61.5% w/v sucrose solution at three different temperatures (25, 35 and 45 °C), with treatment time from 0 to 300 min. Treatment time positively influenced kiwifruit water loss and solid gain while temperature significantly affected only water loss. Peleg’s model highlighted that the main response differences between the two species occurred during the initial phase of the osmotic treatment. Thermal properties and relaxation time measurements offered a complementary view concerning the effects of osmotic dehydration on kiwifruit. DSC parameters appeared to be sensitive to water and solid exchange between fruit and osmotic solution. LF-NMR proton T₂ revealed the consequences of the water–solid exchange on the cell compartments, namely vacuole, cytoplasm plus extracellular space and cell wall. During the osmotic treatment, the initial freezing temperature and the freezable water content decrease was dependent on time and treatment temperature, showing a similar tendency for both the kiwifruit species. They evidenced the same treatment response also concerning the reduction of vacuole and the increase of cytoplasm plus extracellular space T₂ values.     

Mobilization of Macro-nutrients in Cuttings of Kiwifruit (Actinidia chinensis Planch)

Movement was followed of K, Ca, Mg, P and N from wood and barkto the developing shoot of kiwi-fruit cuttings held in waterunder growth-room conditions. K, Mg and P moved to the shootfrom both wood and bark. Ca was the least mobile nutrient andreserves in the wood could account for all the Ca subsequentlyfound in the shoot. About 50 per cent of the calcium in thebark was associated with oxalate. Both wood and bark providednitrogen for the shoot. Soluble N increased with protein hydrolysis.Most of the soluble N in reserves was in the form of arginine.The wood should not be disregarded as an important site of nutrientreserves. Macro nutrient reserves, calcium, nitrogen, magnesium, phosphorus, potassium, Actinidia chinensis Planch., kiwifruit     

Meiotic chromosome pairing behaviour of natural tetraploids and induced autotetraploids of Actinidia chinensis

Key message

Non-preferential chromosome pairing was identified in tetraploid Actinidia chinensis and a higher mean multivalent frequency in pollen mother cells was found in colchine-induced tetraploids of A. chinensis compared with naturally occurring tetraploids.

Abstract

Diploid and tetraploid Actinidia chinensis are used for the development of kiwifruit cultivars. Diploid germplasm can be exploited in a tetraploid breeding programme via unreduced (2n) gametes and chemical-induced chromosome doubling of diploid cultivars and selections. Meiotic chromosome behaviour in diploid A. chinensis ‘Hort16A’ and colchicine-induced tetraploids from ‘Hort16A’ was analysed and compared with that in a diploid male and tetraploid males of A. chinensis raised from seeds sourced from the wild in China. Both naturally occurring and induced tetraploids formed multivalents, but colchicine-induced tetraploids showed a higher mean multivalent frequency in the pollen mother cells. Lagging chromosomes at anaphase I and II were observed at low frequencies in the colchicine-induced tetraploids. To investigate whether preferential or non-preferential chromosome pairing occurs in tetraploid A. chinensis, the inheritance of microsatellite alleles was analysed in the tetraploid progeny of crosses between A. chinensis (4x) and A. arguta (4x). The frequencies of inherited microsatellite allelic combinations in the hybrids suggested that non-preferential chromosome pairing had occurred in the tetraploid A. chinensis parent.     

A COMPARISON OF CLEISTOGAMOUS AND CHASMOGAMOUS FLORAL DEVELOPMENT IN COLLOMIA GRANDIFLORA DOUGL. EX LINDL. (POLEMONIACEAE)

An individual of Collomia grandiflora typically produces both closed or cleistogamous (CL) and open or chasmogamous (CH) flowers. The developmental origin of these dimorphic floral types within a plant was investigated using histological techniques, allometric relationships, and scanning electron microscopy. Prior to archesporal cell stage in the anthers, CL and CH meristems are indistinguishable. In the CL anther, an absence of ventral locule cell differentiation together with a shorter period of time between archesporial cell differentiation and meiosis in the two dorsal locules results in accelerated anther dehiscence and a smaller mature anther size and pollen grain number. Divergence between the CL and CH patterns of corolla development is coincident with microspore mitosis in the CH anther. At this point, there is an increase in growth in corolla length relative to growth in calyx length in the CH flower which does not occur in the CL flower. Calyx and ovary development are similar in the two floral forms; however, ovary expansion due to fertilization occurs earlier in the CL flower as a result of precocious anther development and stigma receptivity. The hypothesis that anther differentiation may trigger organ growth rate changes and differentiation events in the flower and hypothetical roles for abscisic acid and gibberellin in modifying floral development in C. grandiflora are discussed.     

全红型软枣猕猴桃花器结构和开花授粉生物学特性

对全红型软枣猕猴桃天源红花器结构、雌花开放动态及寿命、花期温度、柱头可授性、有效授粉期、有效受精期、花粉管行为等进行了系统研究,以探讨影响天源红结实率低下的原因.结果表明:(1)雌花枝可分为以下5种类型:短缩花枝(0~5 cm)、短花枝(5~10 cm)、中花枝(10~30 cm)、长花枝(30~50 cm)和徒长性花枝(>50cm);(2)柱头属于干性柱头,具有一道裂沟,乳突呈长圆柱形;(3)开花过程可分为以下5个阶段:花萼开裂期、花萼大裂期、花瓣变色期、大蕾期和开花期;(4)整个开花过程温度平稳,开花整齐,雌花单花期为1~2 d;(5)柱头可授性在花后1~2 d最强,花开后3~5 d可授性逐渐降低,花后第6天丧失可授性;有效授粉期为开花第1天和第2天;有效受精时期为授粉后5~10 h;(6)授粉后0.5 h花粉就能在柱头乳突细胞表面萌发并进入花柱道生长;授粉后10 h花粉管生长到达花柱底部.初步推断,花期、有效授粉期以及柱头可授性时间短,是天源红坐果率相对较低的主要原因.     

The Generic Position of Protorhus namaquensis Sprague (Anacardiaceae): Evidence from Fruit Structure

In Protorhus namaquensis the outer epidermis of the ovary formsthe exocarp. At maturity it is uniseriate and consists of palisade-likeparenchyma cells and modified stomata (MS). A cuticle, extensivecutinization of the outer cell walls and starch also characterizethe exocarp. The mesocarp develops from the ground tissue ofthe ovary wall and includes an outer zone of large-celled tanniniferousparenchyma, secretory ducts associated with some of the vascularbundles, prismatic crystals of calcium oxalate and brachysclereids.The inner epidermis of the ovary undergoes successive periclinaldivisions whose derivatives form the mature endocarp. It isstratified and tetraseriate, comprising successive layers (frommesocarp inwards) of crystalliferous cells, brachysclereids,osteosclereids and macrosclereids. The morphology of the femaleflower, and the fruit structure of P. namaquensis are comparedwith that of P. longifolia (lectotype of the genus and onlyother African species) and species of Ozoroa. We present abundantevidence that P. namaquensis should be associated with somemembers of the genus Ozoroa , rather than with P. longifolia.The new combination, Ozoroa namaquensis (Sprague) Von Teichman& Van Wyk, is proposed. Characters of the perianth and pericarp,inter alia the occlusion of the pores of most MS, are consideredadaptations of the species to its harsh semi-desert habitat.Copyright1994, 1999 Academic Press Anacardiaceae, Protorhus namaquensis, Ozoroa namaquensis, pericarp, fruit, flower, modified stomata, ontogeny, histochemistry, cutin     

Meiotic chromosome pairing in Actinidia chinensis var. deliciosa

Polyploids are defined as either autopolyploids or allopolyploids, depending on their mode of origin and/or chromosome pairing behaviour. Autopolyploids have chromosome sets that are the result of the duplication or combination of related genomes (e.g., AAAA), while allopolyploids result from the combination of sets of chromosomes from two or more different taxa (e.g., AABB, AABBCC). Allopolyploids are expected to show preferential pairing of homologous chromosomes from within each parental sub-genome, leading to disomic inheritance. In contrast, autopolyploids are expected to show random pairing of chromosomes (non-preferential pairing), potentially leading to polysomic inheritance. The two main cultivated taxa of Actinidia (kiwifruit) are A. chinensis (2x and 4x) and A. chinensis var. deliciosa (6x). There is debate whether A. chinensis var. deliciosa is an autopolyploid derived solely from A. chinensis or whether it is an allopolyploid derived from A. chinensis and one or two other Actinidia taxa. To investigate whether preferential or non-preferential chromosome pairing occurs in A. chinensis var. deliciosa, the inheritance of microsatellite alleles was analysed in the tetraploid progeny of a cross between A. chinensis var. deliciosa and the distantly related Actinidia eriantha Benth. (2x). The frequencies of inherited microsatellite allelic combinations in the hybrids suggested that non-preferential chromosome pairing had occurred in the A. chinensis var. deliciosa parent. Meiotic chromosome analysis showed predominantly bivalent formation in A. chinensis var. deliciosa, but a low frequency of quadrivalent chromosome formations was observed (1 observed in 20 pollen mother cells).