Stylar End Research Articles

Characterizing Neck Shrivel in European Plum

Neck shrivel is a physiological disorder of european plum (Prunus ×domestica L.) fruit, characterized by a shriveled pedicel end and a turgescent stylar end. Affected fruit are perceived as of poor quality. Little is known of the mechanistic basis of neck shrivel, but microcracking of the cuticle has been implicated. The objective of our study was to quantify transpiration through the skin surfaces of european plums with and without symptoms of neck shrivel. Cumulative transpiration increased linearly with time and was greater in the susceptible european plum cultivar Hauszwetsche Wolff with neck shrivel, compared with fruit of the same cultivar but without neck shrivel and compared with fruit of the nonsusceptible unnamed clone P5-112. Cumulative transpiration of epidermal skin segments (ES) excised from symptomatic ‘Hauszwetsche Wolff’ from near the pedicel end exceeded that from ES excised from near the stylar end. The permeance of ES from near the pedicel end of ‘Hauszwetsche Wolff’ with neck shrivel (12.4 ± 2.6 × 10−4 m·s−1) exceeded that of ES from near the stylar end (2.9 ± 0.4 × 10−4 m·s−1) 4.3-fold. However, in the clone P5-112, the same difference was only 1.6-fold (1.3 ± 0.8 × 10−4 m·s−1 vs. 0.8 ± 0.3 × 10−4 m·s−1). Microscopy revealed numerous microcracks near the pedicel end of symptomatic ‘Hauszwetsche Wolff’ fruit but markedly fewer microcracks near the stylar end. The microcracks near the pedicel end were oriented parallel to the pedicel/style axis, whereas those near the stylar end were randomly oriented. Juices extracted from near the pedicel end of susceptible cultivars had consistently more negative osmotic potentials [ψS (e.g., for Doppelte Hauszwetsche −5.1 ± 0.1 MPa)] than those from near the stylar end (e.g., for Doppelte Hauszwetsche −4.0 ± 0.1 MPa) or that from fruit without symptoms of neck shrivel (e.g., for pedicel end and stylar scar regions of Doppelte Hauszwetsche −3.8 ± 0.1 vs. −3.3 ± 0.1 MPa, respectively). Our results indicate that increased transpiration through microcracks near the pedicel end may contribute to neck shrivel but that the causes of neck shrivel are likely more complex.

Alteration of sugar and organic acid metabolism in postharvest granulation of Ponkan fruit revealed by transcriptome profiling

Granulation is a serious physiological disorder in citrus fruit, accompanied by deterioration of sugars and organic acids, of which the relevant mechanism remains largely unknown. Postharvest granulation was found to begin at the stem region and then gradually extend towards the stylar end of the segment in Ponkan fruit. Hence, stem and stylar juice vesicles within the same fruit with either non-granulation or granulation were analyzed by RNA-Sequencing. Through a comparison of incipient granulated and entire granulated fruit, the results demonstrated that 768 genes were reliably identified to be differentially expressed under granulation. A significant increase in transcript levels was observed in genes encoding enzymes involved in the degradation pathways of sugars and citric acid (e.g., invertase, hexokinase, aconitase, isocitrate dehydrogenase and α-ketoglutarate-dehydrogenase) and in the biosynthesis of cell wall materials including pro-pectin, cellulose and lignin (e.g., UDP-glucuronate 4-epimerase, UDP-glucose pyrophosphorylase and cinnamyl alcohol dehydrogenase) under granulation. Further, there was a distinct decrease in transcript levels of genes encoding enzymes involved in the synthesis pathway of sucrose and citric acid (e.g., sucrose phosphate synthase, sucrose phosphatase, aspartate aminotransferase and malate dehydrogenase) and the degradation pathway of cell wall components (e.g., pectin methylesterase and β-d-xylosidase) under granulation. Together with the decline in content of soluble sugars and acids (sucrose, glucose, fructose, citric acid and malic acid) and the increase in content of cell wall components (lignin, pro-pectin and cellulose) under granulation, the results suggested that sugar and organic acid metabolism adjusted to the synthesis pathway of cell wall components upon granulation at the expense of sugars and acids. This study is the first to unravel the global picture of the network of sugar and organic acid metabolism underlying fruit granulation.

Identification of Conserved and Diverse Metabolic Shift of the Stylar, Intermediate and Peduncular Segments of Cucumber Fruit during Development.

Cucumber (Cucumis sativus L.) is one of the most important vegetables and contains a high content of nutritionally beneficial metabolites. However, little is known about the metabolic variations among different parts of cucumber fruit and their kinetics during growth. In this study, the dynamic metabolic profiles in the stylar end, the intermediate segment and the peduncular end of cucumber fruit during the development were investigated by employing a non-targeted metabolomics approach, where 238 metabolites were identified. Statistical analyses revealed that both development time and tissue type influenced metabolic changes, while development time seemed to exert more effects than tissue type on the cucumber fruit metabolome. The levels of the most of the detected metabolites decreased gradually, while those of some amino acids, carbohydrates and flavonoids increased across development. The metabolomes of the stylar end and the intermediate segment were similar, although all three parts of the cucumber fruit were separated from each other in orthogonal partial least squares projection to latent structures-discriminant analysis (OPLS-DA) plots. Metabolites association analysis revealed that sn-1 and sn-2 lysophospholipids are synthesized via independent pathways in cucumber fruit. In sum, this study demonstrated both conserved and diverse metabolic kinetics of three parts of cucumber fruit, which will facilitate further study of the regulation of cucumber fruit development as well as their potential applications in nutritious quality improvement of cucumber fruit.

Characteristics of Developmental Differences between Fertile and Aborted Ovules in Camellia oleifera

Camellia oleifera is an important woody edible oil plant in southern China. In this study, the developmental differences in ovules at different positions in the ovary of C. oleifera were observed. The developmental type and characteristics of aborted ovules, ratios of normal and aborted ovules, and their developmental differences after flowering were examined. Ovules near the stylar end and in the middle exhibit normal development and are able to form embryo sacs; lower ovules near the pedicel end are usually aborted. The proportion of abortion of four examined cultivars ranges from 10.2% to 33.3%. Aborted ovules can be divided into four categories: 1) nascent egg apparatus lacking distinguishable cells; 2) completely absent egg apparatus structure consisting of flocculent tissue; 3) lack of tissue, comprising only integument cells; and 4) the inner integument not constituting a micropyle channel, with incomplete egg apparatus development and generating abnormal ovules. At 120 days after pollination (DAP), significant distinguishable size differences were found between fertile and aborted ovules; aborted ovules ceased growth at 180 DAP. On fruit maturation, aborted seeds were still attached to the placenta.

Physical rupture of the xylem in developing sweet cherry fruit causes progressive decline in xylem sap inflow rate.

Xylem flow is progressively shut down during maturation beginning with minor veins at the stylar end and progressing to major veins and finally to bundles at the stem end. This study investigates the functionality of the xylem vascular system in developing sweet cherry fruit (Prunus avium L.). The tracers acid fuchsin and gadoteric acid were fed to the pedicel of detached fruit. The tracer distribution was studied using light microscopy and magnetic resonance imaging. The vasculature of the sweet cherry comprises five major bundles. Three of these supply the flesh; two enter the pit to supply the ovules. All vascular bundles branch into major and minor veins that interconnect via numerous anastomoses. The flow in the xylem as indexed by the tracer distribution decreases continuously during development. The decrease is first evident at the stylar (distal) end of the fruit during pit hardening and progresses basipetally towards the pedicel (proximal) end of the fruit at maturity. That growth strains are the cause of the decreased conductance is indicated by: elastic strain relaxation after tissue excision, the presence of ruptured vessels in vivo, the presence of intrafascicular cavities, and the absence of tyloses.

The potential of NIRs as a non-destructive post-harvest quality assessment tool for ‘Triumph’ persimmon fruit

The potential of near-infrared spectroscopy (NIRs) as an alternative non-destructive post-harvest quality assessment tool for ‘Triumph’ persimmon fruit was assessed. Fruits were harvested at four stages of maturity and each stage was replicated four times. Fruit quality was assessed at harvest, after storage and after shelf-life. Spectra data were obtained by scanning three positions on each fruit: green equatorial, yellow equatorial and the stylar end using a multi-purpose analyzer (MPA) spectrometer. Reference data for flesh firmness, total soluble solids (TSS), titratable acidity (TA) and fruit colour were determined using conventional tools on the same fruits from which NIR spectra were obtained. Reference data confirmed that a colour chart cannot categorize fruits into precise distinctive quality classes at harvest. In both the 2012 and 2013 seasons, all measured parameters had overlapping quality ranges across maturity stages. NIRs calibration and validation models showed that NIRs can predict TSS and fruit colour throughout post-harvest storage of ‘Triumph’ persimmon fruit. Furthermore, NIRs has shown some potential to predict firmness and TA by scanning certain fruit positions after storage and after shelf-life. NIRs can therefore be an alternative to the destructive TSS and TA quality assessment tools.

Stone hardening and broken stones in Japanese plums (Prunus salicina Lindl.) evaluated by means of computed tomography scans

Stone breakage causes significant financial losses for the South African Japanese plum export industry as affected fruit must be marketed as Class 2 according to OECD (Organisation for Economic Co-operation and Development) standards. While information exists on split pit in peaches no information could be obtained regarding the development and/or possible protocols to reduce broken stones in Japanese plums. The main aim of this study was, therefore, to determine when and why broken stones develop during fruit development in Japanese plums in an effort to find possible ways to reduce the incidence of the defect in Japanese plums produced in South Africa. X-ray micro computed tomography was used to compare the fruit growth characteristics and endocarp density of ‘Laetitia’ and ‘Sapphire’ (which are highly susceptible to stone breakage) and ‘Songold’ (which is less susceptible to stone breakage) plums during the stone hardening phase of fruit development. Similar to what was found in peaches, this study found that endocarp lignification in Japanese plums started at the stylar end of the stone and progressed towards the stem end between 28–63days after full bloom. Lignification was accompanied by an increase in endocarp density. The inner lining of the plum stones started to harden first, after which lignification continued outwardly. Clear differences were observed between plum cultivars and seasons in the incidence of broken stones. In all instances broken stone manifestation coincided with the commencement of rapid fruit growth before the stones were completely hardened. Since the stones were not completely hardened by the time rapid fruit growth started, the stones were not able to resist the strong pulling forces of the growing mesocarp and were pulled apart.

Stylar end browning: a physiological disorder of Indian jujube (Ziziphus mauritiana) fruits

A physiological disorder has been noted in Indian jujube or ber (Ziziphus mauritiana Lamk.) cv. Chhuhara, wherein tip (stylar end) of the ber fruits turned brown. The disorder has been found to aggravate with the progress in the maturity. The disorder affected fruits had less soluble solids content, reducing and total sugars and ascorbic acid; besides higher content of secondary metabolites and enzymes responsible for oxidative browning. Upon nutrient analyses, the boron content found to be higher in affected fruits in comparison to normal, healthy fruits. Since, this disorder appears during late harvesting period, when atmospheric temperature is higher, it may be concluded that high temperature and evapo-transpiration accompanied with high illumination had resulted in boron accumulation beyond its threshold level, which led to the development of browning of stylar end of fruits in ber cv. Chhuhara.

Ovule positions within linear fruit are correlated with nonrandom mating in Robinia pseudoacacia.

Post-pollination processes can lead to nonrandom mating among compatible pollen donors. Moreover, morphological patterns of ovule development within linear fruits are reportedly nonrandom and depend on ovule position. However, little is known about the relationship between nonrandom mating and ovule position within linear fruit. Here, we combined controlled pollen competition experiments and paternity analyses on R. pseudoacacia to better understand nonrandom mating and its connection with ovule position. Molecular determination of siring success showed a significant departure from the expected ratio based on each kind of pollen mixture, suggesting a nonrandom mating. Outcrossed pollen grains, which were strongly favored, produced significantly more progeny than other pollen grains. Paternity analyses further revealed that the distribution of offspring produced by one specific pollen source was also nonrandom within linear fruit. The stylar end, which has a higher probability of maturation, produced a significantly higher number of outcrossed offspring than other offspring, suggesting a correlation between pollen source and ovule position. Our results suggested that a superior ovule position exists within the linear fruit in R. pseudoacacia, and the pollen that was strongly favored often preferentially occupies the ovules that were situated in a superior position, which ensured siring success and facilitated nonrandom mating.

Rain Cracking in Sweet Cherries is not Due to Excess Water Uptake but to Localized Skin Phenomena

Rain cracking of sweet cherry (Prunus avium L.) fruit is commonly thought to result from excessive net water uptake. This excess increases flesh turgor, which then strains and eventually ruptures the skin at the weakest point. This idea—the critical turgor hypothesis—assumes the fruit comprises a semifluid flesh, held under pressure by a taut skin. The objectives of this study were to test the validity of this popular hypothesis. We investigated the effects of 1) the different pathways of water uptake and 2) the fruit’s water balance on cracking. Incubating fruit of 19 cultivars in water resulted in rapid fruit cracking. The time to 50% cracking (T50) averaged 7.5 ± 1.3 hours with considerable variability between cultivars (T50 range from 1.5 to 18.6 hours). The amount of water taken up at 50% cracking (WU50) averaged 96.5 ± 17.6 mg (WU50 range from 17.7 to 331.5 mg). There was no correlation between either the T50 or the WU50, and the rate of water uptake. Also, there was no correlation between the values of T50 (r = 0.58) and only a weak correlation between the values of WU50 (r = 0.80*) determined in different years. Comparing the value of WU50 under incubation vs. under perfusion revealed a 3.9- to 38-fold higher WU50 under perfusion (397.6 to 1840 mg) than under incubation (48.8 to 102.6 mg). This marked dissimilarity remained, regardless of pretreatments with isotonic polyethylene glycol (PEG) 6000 to induce microcracking or by manipulation of skin wetness during perfusion. Sealing the pedicel/fruit junction markedly decreased the rate of water uptake under incubation. It had no effect on the T50, and it markedly decreased the WU50. Similarly, manually induced skin defects greatly increased the rate of water uptake but, with few exceptions, had no effect on the T50, whereas, the WU50 had increased. The location on the fruit surface of the resulting cracks was not related to the region of the skin in which the manual defect was induced. Allowing the fruit to transpire increased both, the T50 and the WU50. Interestingly, the amount of water lost by transpiration exceeded the amount that was subsequently required to cause cracking up to 5-fold. Incubating fruit with their stylar ends immersed in water, whereas their remaining surfaces were in air of 0%, 28%, 75%, or 100% relative humidity (RH) resulted in net losses of water of up to 5.9 ± 0.7 mg·h−1, nevertheless their stylar ends still cracked. All our results indicate rain cracking in sweet cherries is a localized phenomenon that is not related to the net fruit water balance (the critical turgor hypothesis) but is the result of more local exposure of the fruit skin to liquid-phase water (the zipper hypothesis).

Uneven distribution of flavour components in tablegrape berries

Background and Aims The basic taste of grapes is determined by the sugars, acids and their ratio while the cultivar flavour results from its unique profile of volatile compounds. So far, the general perception is that flavour components are evenly distributed in grape berries. In the current study, the composition of TSS, titratable acidity (TA) and volatiles was examined in the stem and stylar ends of tablegrapes. Methods and Results Values of TSS were up to 2°Brix higher, and TA values were up to 1.5-fold higher in the stylar end compared with that in the stem end of the berries. Coating the berries at veraison with wax to reduce evaporation decreased TSS accumulation and the stem-end versus stylar-end difference in TSS and TA. Volatile concentration differed significantly in berry tissues in an opposite pattern being higher in the stem than in the stylar ends of the berries. Conclusions Our findings indicate that there is a substantial difference in the composition of the stem and stylar end of tablegrape berries. It is also suggested that transpiration may play a role in the uneven distribution. Significance of the Study These results are novel for tablegrapes and are likely to contribute significantly to the understanding of flavour accumulation in grapes.

Phytotoxic effect of GF-120 NF fruit fly bait on fruit of mandarin (Citrus reticulata Blanco cv. Nadorcott): Influence of bait characteristics and fruit maturity stage

The phytotoxicity of the fruit fly bait GF-120 NF (containing 0.24 g/L spinosad and fruit fly attractants including a protein hydrolysate, ammonium acetate and a number of additives including sugar, polyethylene glycol, polysorbate and soybean oil) on fruit of mandarin (Citrus reticulata Blanco cv. Nadorcott) was investigated in an orchard in Mpumalanga, South Africa. Trials were conducted on ‘Nadorcott’ mandarin fruit at different stages of maturity. Droplets of GF-120 were applied on marked areas at the stylar ends of fruit in the orchard. The effects of GF-120 concentration, droplet size, droplet coverage and bait wetness on incidence of phytotoxicity were determined.Phytotoxicity of GF-120 was recorded on ‘Nadorcott’ mandarin fruit which were at the green and colour-break stages. Incidence of burn increased with increasing concentration of GF-120. Phytotoxicity of GF-120 was accentuated with increasing droplet size, droplet coverage and prolonged wetness of bait droplets. No phytotoxicity was observed when GF-120 was applied on Nadorcott mandarin at full rind colour development.Alternative methods of GF-120 application other than ground-based canopy sprays would therefore have to be sought for ‘Nadorcott’ mandarin orchards, especially if baiting is to start early before full colour development. Use of other fruit fly management techniques such as bait stations would also help avoid the risk of phytotoxicity on fruit of ‘Nadorcott’ mandarin at the green and colour break stages.

English

The ber (Ziziphus mauritiana Lamarck) is an important fruit crop grown in arid and semi arid regions of India and elsewhere. Nutritionally, the fruits are rich in protein, phosphorus, calcium, carotene and vitamin C. In India, productivity tends to be low because of various biotic stresses such as pests and diseases. Of the various insect pests infesting ber, the stone weevil Aubeus himalayanus Voss (Coleoptera:  Curculionidae) is a new threat to ber cultivation in India. This was recorded as a new pest of ber in India for the first time in the state of Andhra Pradesh in 1994. Serious attacks were later reported in Rahuri, Maharashtra and Jobner, in 1996, and in Karnataka during 1998. Recently, infestations of this pest were reported in Bikaner and Rajasthan in 2010 and in Bangladesh in 2009. The females lay their eggs on the stylar end of fruits, or rarely on the distal end. The newly emerged white coloured grubs enter the seeds by making a puncture in the endocarp of the immature fruits, and starts feeding on the soft seed coat. Later it enters the endosperm, feeds on it, and pupates within the seed. The weevil completes its life within a single fruit. The infestation results in severe fruit drop at the initial stage of fruit set. The damage intensity of the stone weevil varies with cultivars; stoned varieties are preferred more than the pulp rich varieties. Periodical monitoring of orchards for weevil incidence is essential for timely implementation of control strategies. Delayed detection makes management difficult as they enter the seed.   Key words: Ber, Ziziphus mauritiana, stone weevil, Aubeus himalayanus.

Pollen effects on fruit attributes and seed properties in colchicine-induced autotetraploids of red-fleshed kiwifruit (Actinidia chinensis Planch.)

SUMMARYThe effect of the ploidy level of the polleniser has not been considered during the characterisation and evaluation of colchicine-induced autotetraploids of Actinidia chinensis (kiwifruit). It is therefore possible that few induced autotetraploids reach their potential size. Five genotypes of tetraploid pollenisers were used for controlled pollination of red-fleshed autotetraploids. Fruit of colchicine-induced autotetraploids from two genotypes of female red-fleshed A. chinensis plants were, on average, 25–30% larger than fruit arising from open-pollination in an orchard containing only a diploid male as polleniser. Fruit dimensions increased more in cross-section than in length, so the fruit were more round. Seed set increased up to two-fold and the number of filled seeds also increased significantly (P ≤ 0.01). The average filled-seed weighed two-to-three times more than that of seed from open-pollination with pollen from a diploid male, and were heavier than those in fruit of their diploid progenitors under open-pollination. The distribution of the red-flesh pigmentation increased, although its intensity was not significantly improved. The total soluble solids content (TSSC) increased by 1–2% and the size of the core cavity at the stylar end was significantly reduced (P ≤ 0.01) and sometimes completely. All these effects on fruit attributes would benefit the commercial cultivation of red-fleshed kiwifruit. It is therefore recommended that, as for diploids, pollenisers of tetraploid red-fleshed kiwifruit should be of matching ploidy. Two abnormal fruit with soft red cores were found on a branch of a tetraploid regenerant during the evaluation of fruit generated by controlled pollination. The possible origin and application of this mutation for novel kiwifruit breeding are also discussed.

Foliar 2,4-D Application after Physiological Fruit Drop Reduces Fruit Splitting of Mandarin

Various mandarin (Citrus reticulata) cultivars are prone to fruit splitting, a physiological disorder that entails cracking of the rind, starting from the stylar end of the fruit, with eventual splitting of the endocarp and abscission of the fruit. On two mandarin cultivars, Marisol and Mor, foliar applications of 2,4-dichlorophenoxyacetic acid (2,4-D), calcium (Ca), and potassium (K) were evaluated over two growing seasons for efficacy to reduce fruit splitting in Paarl, South Africa (lat. 33°69′S, long. 18°95′E). Foliar treatment of 10 mg·L−1 2,4-D directly after physiological fruit drop (APFD) compared with later dates in January and February, either alone or in combination with K, increased rind thickness and reduced fruit splitting of ‘Marisol’ and ‘Mor’ by up to 50%, without negatively affecting internal fruit quality. Treatments increased rind thickness and rind strength throughout fruit development in addition to fruit diameter, length, and growth rate, with no significant effect on rind coarseness. There was a slight reduction in juice content and titratable acidity (TA), but no effect on the total soluble solids (TSS). Application of 2,4-D APFD is thought to increase rind integrity due to a direct strengthening effect on the rind during early stages of fruit development.

CHARACTERISTICS OF BERRY GROWTH IN CRACKING SUSCEPTIBLE TETRAPLOID GRAPEVINES

Berry cracking is one of the most serious problems for high quality table grape cultivation using tetraploid cultivars in Korea. Berry cracking patterns and factors were investigated through growth characteristics and morphological observation of berry between two tetraploids (?Fujiminori? and ?Kyoho?) and compared with diploid ?Campbell Early? which has different cracking susceptibility of berry. The stomata were scattered on ovary surface at full bloom stage and numbers of stomata were different: 16.5 in ?Fujiminori?, 14.7 in ?Kyoho?, and 9.95 in ?Campbell Early?. The numbers of stomata at veraison stage, however, changed depending on location of berry to 9.8 (stylar end trisection), 6.2 (equatorial trisection), and 3.6 (stem end tri¬section) in ?Fujiminori? and 5.3, 7.7, and 1.7 in ?Kyoho?, and 2.7, 3.9, and 3.2 in ?Campbell Early?. As berry growth advanced, patterns of distributed stomata changed and were different in each cultivar. The berry cracking rate at veraison of ?Fuji¬minori? and ?Kyoho? was remarkably high, 13.2 and 7.0%, compared with 0.6% in ?Campbell Early?. Berry cracking-sensitive ?Fujiminori? and ?Kyoho? grapes showed rapid berry growth at stage III after veraison compared with cracking-insensitive ?Campbell Early?. Depending on the locations of berry divided into the stylar end, equator, and stem-end, cracking rates were also different with 59.0, 34.5, and 6.5% in ?Kyoho? and 74.5, 12.5, and 12.0% in ?Fujiminori?. After the veraison stage, larger cracking of berry was observed from the fruit lenticels which were degenerated from stomata and stylar scar in ?Fujiminori? compared with cracking resistant ?Campbell Early? grape.

<I>Herpetospermum operculatum</I> (<I>Schizopeponeae</I>, <I>Cucurbitaceae</I>), a new species from India, Myanmar and China

A new species of Herpetospermum (Schizopeponeae, Cucurbitaceae) is described from north-eastern India, northern Myanmar and southwest China (Xizang and Yunnan). Herpetospermum operculatum was previously confused with Herpetospermum (= Biswarea) tonglense, but differs primarily in having smooth yellow-striped fruit with operculum at stylar end, ascendent seed arrangement in fruit and prominent probracts and bracts. At least a part of the collections of Herpetospermum tonglense in Myanmar and China represent misidentification of this species.

TWO ASTRINGENT PERSIMMON CULTIVARS RELEASED BY NARO INSTITUTE OF FRUIT TREE SCIENCE, JAPAN

The national institute in Japan has conducted persimmon breeding since 1938, emphasizing the improvement of pollination constant non-astringent (PCNA) cultivars. However, PCNA cultivars of Japanese origin is a recessive trait, and its genetic resources are very limited, and repeated crossings within the narrow gene pool led to inbreeding, which hinders tree vigor, productivity, and fruit weight. Therefore, a strategy of obtaining PCNA offspring through the backcross (PCNA×non-PCNA)×PCNA has been going on since 1990. Two astringent selections from the first phase were released as new pollination variant astringent (PVA) cultivars ‘Taiten’ and ‘Taigetsu’ in 2007, both of which are derived from the cross of ‘Kurokuma’ (a local PVNA cultivar in Japan) × PCNA cultivar ‘Taishu’. Trees of both new cultivars are vigorous and productive. Crosses between each of those new cultivars and PCNA genotype yielded around one fifth PCNA offspring of the total. The ‘Taiten’ fruit ripens in late November, comparable to ‘Fuyu’ at the national institute in Akitsu. Its fruit weighs an average of 506 g. The flesh is soft, moderately coarse and very juicy. The soluble solids concentration in juice after removing astringency (SSC) averages 16.5%, which is comparable to ‘Fuyu’. Fruit cracking at the calyx or stylar end is rare. However, small areas of shallow concentric cracks on fruit skin (SCCS) occur in a considerable ratio of the fruit. The ‘Taigetsu’ fruit ripens in early November at Akitsu. Its fruit weighs an average of 459 g. The flesh is soft, moderately coarse and very juicy. The SSC averages 15.4%, which is comparable to ‘Hiratanenashi’. Fruit cracking at the calyx or stylar end is rare. SCCS are likely to occur in a considerable ratio of the fruit. Parthenocarpy in ‘Taigetsu’ is high.

Fruit ripening in Vitis vinifera: spatiotemporal relationships among turgor, sugar accumulation, and anthocyanin biosynthesis.

This study reports the first observations indicating the spatiotemporal relationships among genetic and physiological aspects of ripening in the berry of Vitis vinifera. At the onset of ripening in the red flesh variety Alicante Bouschet, colour development began in the flesh at the stylar end of the fruit and progressed toward the pedicel end flesh and into the skin. Tissue solute potential and cell turgor also decreased first in the flesh. The decrease in flesh solute potential was due to accumulation of sugars, glucose and fructose, an accumulation that is integral to ripening. Expression of the anthocyanin biosynthesis-related genes VvMybA and VvUFGT was linearly related to the decrease in solute potential. Expression of VvMybA, and to a lesser extent VvUFGT, was correspondingly low in green tissue, higher in the red, stylar end flesh of berries beginning to ripen, and greatest in red berries. In contrast, expression of the abscisic acid biosynthesis-related genes VvNCED1 and VvNCED2 was not correlated with the other spatiotemporal aspects of the onset of ripening. These results, together with earlier work showing that sugar accumulation and acid loss also begin in the stylar flesh in other varieties, indicate that ripening in the grape berry originates in the stylar end flesh.

Phytohormone Changes and Carbohydrate Status in Sweet Orange Fruit from Huanglongbing-infected Trees

Huanglongbing (HLB) infection alters citrus fruit growth and development, resulting in small, misshapen, and poorly colored fruit containing aborted or partially developed seeds. Typically, symptomatic fruit have delayed maturation and abscise prematurely. We studied carbohy- drate and phytohormone changes in HLB-affected fruit to explain symptom development because (1) carbohydrate shortage has been linked to fruit growth arrest and eventually abscission and (2) hormonal signals regulate, at least par- tially, fruit set and development. Symptomatic fruit (S), asymptomatic fruit (AS) from symptomatic trees, and healthy fruit (H) from asymptomatic trees were harvested from 'Valencia' sweet orange trees (Citrus sinensis (L.) Osbeck) infected with the HLB pathogen or not, as verified by PCR. Mature S weighed less, had lower Brix, were smaller, had more aborted seeds, and were greener than AS or H. Starch and sucrose contents were lower in mature S flavedo compared with that of H and AS. S and AS harvested 7 and 12 months after full bloom produced significantly less ethylene than H. Indole-3-acetic acid (IAA) and abscisic acid (ABA) contents in flavedo removed from the stylar end, middle section, or stem end of fruit generally were higher in S flavedo than in AS and H. ABA content was fourfold higher in flavedo from the middle section of S than in AS and H. Flavedo excised from the large shoulder of misshapen S had significantly higher IAA content when compared with the normal-sized area of the same fruit on the opposite side. This increase corresponded to an increase in hypodermal cell area in S flavedo. Overall, these data reveal an imbalance of carbohydrate and phytohormone status in fruit from HLB- infected trees and suggest a role of such changes in fruit symptom development.