Fruit Calyx Research Articles

Study on biological activities of Physalis alkekengi var. francheti polysaccharide

AbstractBACKGROUND: Physalis alkekengi var. francheti is a well‐known edible and medicinal plant in oriental countries. Recent reports indicate that polysaccharides play an important role as a dietary free radical scavenger for the prevention of oxidative damage.RESULTS: Antioxidant studies showed that fruit polysaccharide (FP) had higher scavenging effects on 1,1‐dipheny‐l‐2‐picrylhydrazyl, hydroxyl radical assay (·OH) than vitamin C and fruit calyx polysaccharide (FCP) in vitro. The results of animal experiments showed that D‐galactose‐induced aging in mice, as evidenced by alterations in superoxide dismutase, glutathione peroxidase, catalase and monoamine oxidase activities and malondialdehyde level, was ameliorated by FP treatment. Moreover, FP could distinctly prolong the loaded‐swimming time of mice, lower the content of blood urea nitrogen of post‐exercise mice, decrease the consumption of liver glycogen and increase the activity of lactic dehydrogenase. All these results suggested that FP functioned in resisting the production of fatigue and accelerating the dispelling of fatigue.CONCLUSION: The present study suggests that Physalis alkekengi var. francheti would be a valuable source of polysaccharide and FP is able to effectively scavenge free radicals, delay aging in mice and resist the production of fatigue. Copyright © 2009 Society of Chemical Industry

Diversity in commercial varieties and landraces of black eggplants and implications for broadening the breeders’ gene pool

AbstractBlack‐coloured eggplants (Solanum melongena) represent the commercially most important group of eggplants in Europe and North America. Most of the modern varieties of black eggplants correspond to F1 hybrids, which at the same time constitute an elite gene pool for the development of new varieties. However, there are many black landraces and old varieties, which could be useful as sources of variation for black eggplant breeding programmes as well as for the broadening of the genetic diversity of the breeders’ gene pool. We have studied the morphological and molecular [amplified fragment length polymorphism and simple sequence repeat (SSR)] diversity in a collection of 38 black eggplant accessions, including commercial (modern F1 hybrid and old nonhybrid) varieties and landraces as well as in six nonblack control eggplants, from different origins. The results show that black eggplants contain a considerable morphological and molecular diversity, but commercial varieties, and in particular F1 hybrids, display a reduced morphological and molecular diversity when compared with landraces. The principal components analysis morphological and principal coordinates analysis molecular analyses show that commercial F1 hybrids group together, indicating that they share a common and narrow gene pool. Commercial F1 hybrids present a series of productive advantages, like early production, intense black colour (low L*, a* and b*) values and absence of fruit calyx prickles. However, several of the landraces and old nonhybrid varieties studied present a high yield as well as other traits of interest for eggplant breeding. Furthermore, given the low genetic diversity of F1 hybrids and the moderate level of SSR heterozygosity found in these materials (0.382), introduction of black landraces and old varieties in the present breeding programmes could contribute to broadening the gene pool used by breeders and this could help increase the heterosis for yield of F1 hybrids, which is greatly favoured by high heterozygosity levels.

Polysaccharides from fruit calyx of Physalis alkekengi var. francheti: Isolation, purification, structural features and antioxidant activities

The conditions for extracting and purifying polysaccharides from fruit calyx of Physalis alkekengi var. francheti were investigated , including hot water extraction, ultrasonic wave-assistant extraction and enzyme extraction methods. Four polysaccharide fractions (PAVF I, II-a and III) were separated from the extracts of fruit calyx of P. alkekengi var. francheti using a DEAE anion-exchange column and Sephadex G-200 column. Their chemical compositions were determined in this study. On the basis of hydroxyl radical assay ( OH), superoxide radical assay, 1,1-dipheny-l-2-picrylhydrazyl (DPPH) assay, the antioxidant activities of crude polysaccharide from fruit calyx of P. alkekengi var. francheti (FCP), PAVF I, II-a, -b and III were investigated. Among these contents, PAVF I has higher scavenging effects on DPPH, OH and superoxide anion-scavenging activities.

Distinguishing a protected geographical indication vegetable (Almagro eggplant) from closely related varieties with selected morphological traits and molecular markers

AbstractBACKGROUND: Certification of the authenticity of local landraces having a Protected Geographical Indication (PGI) status is essential when fake exotic varieties can be used to replace authentic local varieties. The Almagro eggplant (Solanum melongena) is a landrace used for making pickle products recognized by PGI status. Other pickling varieties from the region of Andalusia that are closely related have been detected in fields of the Almagro region. We have studied the diversity of Almagro and Andalusian accessions with morphological traits and molecular markers (amplified fragment length polymorphisms (AFLPs) and simple sequence repeats (SSRs)) with the aim of obtaining a characteristic fingerprint of the Almagro eggplant.RESULTS: Almagro eggplants have smaller plant parts and greater prickliness than Andalusian eggplants. No overlap in the ranges of variation was found between Almagro and Andalusian accessions for three traits (fruit pedicel width at the proximal end, fruit calyx length, and fruit calyx prickles). AFLP characterization showed that Almagro and Andalusian accessions are genetically diverse and share a common genetic background. On the other hand, SSR, allowed a clear distinction of Almagro and Andalusian varieties, and for two SSRs we found alleles exclusive of Almagro eggplant and universal to all Almagro accessions.CONCLUSION: By using selected morphological descriptors and specific molecular markers we have been able to distinguish the PGI Almagro eggplant from closely related varieties. SSRs have proved useful for detecting differences between the closely related Almagro and Andalusian accessions. The approach followed by us can be used for the protection and enhancement of other PGI vegetable crops. Copyright © 2008 Society of Chemical Industry

Alternaria alternata fruit rot of pomegranate (Punica granatum) in Greece

During September and October 2005 and 2006 a fruit disease was observed in pomegranate orchards, in the region of Larissa, Central Greece, causing significant yield losses of approximately 40–50% especially on cv. Kapmaditika. Internal symptoms consisted of a black rot of the fruit core beginning from the calyx area, while the hard, leathery rind appeared healthy and fruits remained firm. Alternaria alternata was consistently isolated from infected tissues, and the identification of the fungus was based on morphological characteristics of mode of sporulation and conidia (Simmons, 1967). Conidiophores were short, septate, branched or unbranched, and green to brown. The conidia were obpyriform with conical or cylindrical beak, ovoid or ellipsoidal. They were produced in long, single but most often branched, chains. Conidia ranged from 10 to 21 µm in length and from 4 to 10 µm in width at the broadest point (average 17 × 6 µm). Cultures grew rapidly on potato dextrose agar (PDA), and they were initially white turning to grey later. The isolate was deposited in CBS International Culture (CBS 120829). Pathogenicity tests were conducted on fruits and were repeated three times. PDA-plugs, 5 mm in diameter, with actively grown mycelium were transferred into the fruit calyx as well as on wounds made by a scalpel on previously sterilized fruit surfaces. Following inoculation, the fruits were placed in plastic bags and kept at 23oC for 10 days. Fruits inoculated in the same way using PDA disks were kept as control. Although there were no external symptoms on any of the fruits, decay of the core was observed when inoculated fruits were cut vertically. Control fruits showed no decay. Alternaria alternata was reisolated from inoculated fruits, confirming Koch's postulates. Alternaria alternata has been reported to cause a leaf spot disease on pomegranate in India (Madhukar & Reddy, 1976) however, fruit rot was not reported. Fruit rot caused by Alternaria sp. has previously been reported in USA, Mexico (Farr et al., 2007), and as a postharvest disease in Greece (Pantidou, 1973). Although this disease has been detected before in Greece, it was noticed again only recently probably due to the recent expansion of pomegranate cultivation and changes in weather conditions. This is the first report of A. alternata causing fruit decay in pomegranate orchards in Greece.

Deprea nubicola (Solanaceae), a new species from northern Colombia

A new species,Deprea nubicola, is described. Although the corolla is similar in some aspects to that ofD. bitteriana, D. nubicola is distinguished by its diminutive leaves, a low density of hairs in the corolla annulus, glabrous filaments, and a distinctive long-pedicellate, subulate-lobed fruiting calyx.Deprea nubicola shares withD. ecuatoriana a fruiting calyx that tightly invests the berry. The distribution ofD. nubicola is limited to the Sierra Nevada de Santa Marta of northern Colombia. A key to the species ofDeprea is provided.

Involvement of phospholipase D and lipoxygenase in response to chilling stress in postharvest cucumber fruits

Harvested cucumber ( Cucumis sativus L. cv. Jinyou-1) fruits were placed at 37 °C (pre-warming) or at 20 °C (control) for 24 h prior to be stored at 2 °C for 9 days. After storage, fruits were cut into three sections with equal length, namely top (calyx end), middle and bottom (stalk end), respectively. In order to determine the responses of phospholipase D (PLD) and lipoxygenase (LOX) to chilling stress, their activities and expression pattern of PLD gene in three sections of cucumber fruits were measured when the symptoms of chilling injury first appeared as numerous tiny pits. Chilling injury assessed as chilling injury index and electrolyte leakage occurred initially in the top area near calyx of fruits, and developed toward the bottom near stalk. This spatial development of chilling injury was in parallel with the gradients of PLD and LOX activities and PLD mRNA levels. Alleviation of chilling injury by pre-warming treatment was related with increased content of membrane-associated Ca 2+, suppressed expression of PLD mRNA, and reduced activities of PLD and LOX. We suggest that PLD and LOX are associated with the initiation of chilling injury by involving in membrane deterioration and signaling pathway in response to chilling stress.

Pre-harvest nickel application to the calyx of ‘Saijo’ persimmon fruit prolongs postharvest shelf-life

Since nickel ions (Ni 2+) have an inhibitory effect on 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase by replacing iron (Fe 2+) and forming an enzyme-metal complex. 0.1% (w/v) NiCl 2 solution was sprayed onto the calyx of persimmon fruit ( Diospyros kaki Thunb. cv Saijo) twice before harvest. Ni 2+-treatment effectively inhibited ‘Saijo’ fruit softening, and prolonged the fruit shelf-life for 2 days by delaying ACC accumulation and ethylene production. However, non-treated control fruit rapidly softened on the fifth day due to the immediate increase in ACC levels and ethylene production after the removal of astringency. Relatively firm Ni 2+-treated fruit were observed on day 7, at which point the control fruit had completely softened. Northern blots indicated that only slight DK-ACS1 transcription could be observed on day 6 in Ni 2+-treated fruit, whereas abundant DK-ACS1 mRNA was transcribed on day 5 in non-treated fruit. Correspondingly, ACC synthase activity was delayed with the Ni 2+-treatment, whereas it had little effect on ACC oxidase activity. We propose that Ni 2+ could be exploited as an effective new reagent to prolong persimmon shelf-life via pre-harvest treatments.

Enumerative and Binomial Sampling Plans for Citrus Mealybug (Homoptera: Pseudococcidae) in Citrus Groves

The spatial distribution of the citrus mealybug, Planococcus citri (Risso) (Homoptera: Pseudococcidae), was studied in citrus groves in northeastern Spain. Constant precision sampling plans were designed for all developmental stages of citrus mealybug under the fruit calyx, for late stages on fruit, and for females on trunks and main branches; more than 66, 286, and 101 data sets, respectively, were collected from nine commercial fields during 1992-1998. Dispersion parameters were determined using Taylor's power law, giving aggregated spatial patterns for citrus mealybug populations in three locations of the tree sampled. A significant relationship between the number of insects per organ and the percentage of occupied organs was established using either Wilson and Room's binomial model or Kono and Sugino's empirical formula. Constant precision (E = 0.25) sampling plans (i.e., enumerative plans) for estimating mean densities were developed using Green's equation and the two binomial models. For making management decisions, enumerative counts may be less labor-intensive than binomial sampling. Therefore, we recommend enumerative sampling plans for the use in an integrated pest management program in citrus. Required sample sizes for the range of population densities near current management thresholds, in the three plant locations calyx, fruit, and trunk were 50, 110-330, and 30, respectively. Binomial sampling, especially the empirical model, required a higher sample size to achieve equivalent levels of precision.

Seasonal and Cultivar-Associated Variation in Oviposition Preference of Oriental Fruit Moth (Lepidoptera: Tortricidae) Adults and Feeding Behavior of Neonate Larvae in Apples

The Oriental fruit moth, Grapholita molesta (Busck) (Lepidoptera: Tortricidae) has become a pest of tree fruits since its introduction to the United States in the early twentieth century. Oriental fruit moth has historically been a major pest problem in peach production, and outbreaks in commercial apple (Malus spp.) orchards in the eastern United States were rare until the late 1990s. Recent outbreaks in Mid-Atlantic apple orchards have lead researchers to investigate host-associated effects on oriental fruit moth biology, behavior, and population dynamics. Studies were designed to assess cultivar level effects in apples on oviposition and larval feeding behavior of oriental fruit moth. In a mixed cultivar apple orchard, total oriental fruit moth oviposition and oviposition site preferences varied between cultivars. These preferences also varied over time, when sampling was repeated at various times of the growing season. Although most adult female oriental fruit moth preferentially oviposited in the calyx and stem areas of apple fruit, noticeable numbers of eggs also were laid on the sides of fruit, contradicting some previous reports. Oriental fruit moth females exhibited a strong ovipositional preference for fruit that were previously damaged by oriental fruit moth or codling moth, Cydia ponmonella (L.). The majority of newly hatched oriental fruit moth larvae were observed to spend <24 h on the surface of apple fruit before entry, and this behavior was observed on several apple cultivars. Neonate larvae exhibited a preference for entering fruit at either the stem or calyx ends, regardless of their initial site of placement. Our findings underscore the importance of adequate spray coverage and accurate timing of insecticide applications targeting oriental fruit moth.

ACCUMULATION OF PHYSALIN IN CELLS AND TISSUES OF PHYSALIS MINIMA L.

Accumulation of physalin was investigated in the intact tissues of P. minima at different developmental growth stages and locations and compared with that in cell cultures. Results showed that this compound was mainly accumulated in mature plants, that is higher physalin content was observed in fruiting plants flowering and juvenile plants. Different tissues were also observed to vary in the physalin accumulation. Physalin A was mostly accumulated in the young fruit, physalin B in the young leaf and flower bud, physalin D in the flower bud, physalin F in the mature leaf, physalin J in the immature and ripe fruit calyx, and physalin N in the leaf tissues. The content of physalin in intact plant tissues varied from 0.07 to 9.89 mg g-1 DW. Physalin yield in the fruit was mainly located in the seeds. Physalin accumulation in specific tissues of a particular plant, however appeared to be greatly affected by environmental and geographical factors. The accumulation levels of physalin in cell cultures were 2.2-11.5 folds lower than that in intact plant tissues.

Mechanical wounding and abscission in citrus

Fruit detachment force (FDF), ethylene evolution, fruit and leaf drop were determined in Citrus sinensis for periods up to 96 h after mechanical wounding. Injury by removing a thin section of mature fruit flavedo reduced FDF, increased ethylene evolution and promoted abscission. Injuring flavedo 1 cm below the calyx was more effective at reducing FDF than injuring flavedo at the equator or the blossom‐end of mature fruit. Injuring the calyx or peduncle of mature fruit, or injuring three leaves closest to the mature fruit did not reduce FDF. Immature fruitlets either did not abscise or underwent low rates of abscission in response to mechanical wounding, depending on age. Inhibiting ethylene binding in wounded mature fruit with 1‐methylcyclopropene (1‐MCP) increased ethylene evolution compared with wounded fruit alone, but the reduction in FDF was similar. When an ethylene biosynthesis inhibitor (aminoethoxyvinylglycine, AVG) was used, reduction in FDF of wounded mature fruit exposed to AVG was similar to that of wounded fruit alone but ethylene production was markedly reduced. Wounding mature leaf blades in the presence or absence of 1‐MCP resulted in elevated but equal ethylene evolution up to 48 h after wounding, however, no leaf drop occurred. Thereafter, ethylene evolution was higher in 1‐MCP‐treated wounded leaves. Removing up to 77% of the total mature leaf area did not cause leaf drop, nor did wounding tissue across the laminar or petiolar abscission zones. Leaflets of 5 mm length reached nearly 100% abscission after mechanical wounding, whereas wounding leaves 20 mm length resulted in 15% abscission. The data suggest that mechanical wounding of flavedo results in mature fruit abscission, and ethylene binding may not be mandatory to initiate abscission in citrus fruit. The differential response of fruit and leaves at different ages to wounding may be related to potential contribution to carbohydrate accumulation, and production and sensitivity of tissues to an abscission signal(s).

Colonization of growing fruit by the armored scales Lepidosaphes beckii, Parlatoria pergandii and Aonidiella aurantii (Hom., Diaspididae)

Abstract: The process of invasion of the fruit surface by three species of armored scale insects [Lepidosaphes beckii (Newman), Parlatoria pergandii Comstock and Aonidiella aurantii (Maskell)], was studied in citrus orchards in València, Spain. Three periods of intense crawler migration were detected annually for L. beckii and P. pergandii. Abundance of crawlers increased throughout the year and they moved outwards in the tree canopy. The fruit was continuously invaded during the period of fruit growth, starting at a very early stage of fruit development, by crawlers of the first generation of all the three species. Differences in fruit invasion and settling behaviour were found between the three species. First‐generation crawlers tended to settle under the fruit calyx in L. beckii and P. pergandii, and on the exposed fruit surface in A. aurantii. During the second generation, most A. aurantii scales originated from reproducing females already settled on the fruit, whereas in L. beckii and P. pergandii new scales came preferentially from other tree substrates or from females settled under the fruit calyx. These findings suggest changes to optimize the timing of chemical sprays for controlling the scales.

Field evaluation of commercial formulations of the codling moth granulovirus: persistence of activity and success of seasonal applications against natural infestations of codling moth in Pacific Northwest apple orchards

Inundative applications of the codling moth (CM), Cydia pomonella L., granulovirus (CpGV), which target neonate larvae before or during initial entry into fruit, offer potential for selective control of this key pest. In field tests on apple we compared the persistence and efficacy of single applications of three CpGV products approved for organic orchards in North America. In addition, the success of repeated (2–14) applications of one product (Cyd-X) as a principal control measure for CM in apple orchards was monitored following operational use by cooperating growers at four separate locations. In the first study, an early season application of all products at label rates remained highly effective for the first 24 h (averaging 94% larval mortality relative to controls) and moderately effective after 72 h (averaging 71% mortality) during dry sunny conditions. Significant activity remained up to 14 days, suggesting prolonged survival of the virus in UV-protected locations, such as the calyx of fruit. A second application later in the season was slightly less effective. Data obtained from commercial sites provide circumstantial evidence for the effectiveness of well-timed CpGV applications against CM outbreaks. In all cases where first generation larvae were targeted beginning at egg hatch (≈250 degree days) and treated areas monitored (0.3–1.6 ha plots), fruit damage during the second larval generation was reduced or eliminated. Based on the number of live larvae recovered throughout the season, mortality rates remained high (80.3–100% across sites). The cumulative number of moths caught in pheromone-baited traps was reduced (66–94%) in the second flight. Data from tree bands placed to catch diapause-destined larvae indicated overwintering generations remained low in treated sites (⩽0.18 larvae/band).

EFFECT OF TOMATO FRUIT PEDICEL TEMPERATURE ON FRUIT EXPANSION PREDICTED BY A MODEL BASED ON PEDICEL CONDUCTIVITY

In a model of tomato fruit expansion which has been proposed recently (Bussieres, 2002), the water import in the fruit is based on the values of various parameters of the stem, the fruit pedicel, the fruit calyx and the fruit. In this model, one important parameter is the fruit pedicel phloem conductivity: based on literature data, this model has found phloem conductivity to be an increasing function of the fruit size, probably due to the increasing size of elements of the sieve tubes in the pedicel phloem. As the conductivity of a tube in which a liquid flows increases when the liquid viscosity decreases, and as the viscosity decreases when the temperature increases, a positive effect of the temperature of fruit pedicel on fruit expansion has to be inferred. Therefore, the model of fruit expansion was used to calculate the difference in the fruit mass changes over time due to a difference in the temperature of the fruit pedicel. When temperature was 30°C rather than 18°C, fruit mass was found to be only higher over the first weeks after pollination, whereas final fruit mass was only slightly changed. These predictions will have to be confirmed by further measurements.

Effects of acetaldehyde on fruit quality and target pest mortality for harvested strawberries

Strawberry fruit and western flower thrips were exposed to 1, 2, 3, or 4% acetaldehyde (Aa) for 2 h in air or in 20 kPa CO2. Following treatment, fruit were stored at 0 or 20 8C for 4 or 2 days, respectively. Aa treatment did not significantly impact fruit firmness, color, or soluble solids content; however, calyx damage increased with increasing concentration of Aa. Strawberry fruit tolerated exposure to 1 or 2% Aa with little or no damage to the fruit calyx. Fruit Aa, ethanol, and ethyl acetate concentrations increased initially, but decreased over time; the decrease being greater in fruit stored at 20 8C as compared with 0 8C. Methanol and acetone levels were lower in treated than untreated fruit. Western flower thrips were not completely controlled by any of the treatments, but � /95% mortality was achieved by a 2 h exposure to 3 or 4% Aa. The presence of 20 kPa CO2 enhanced mortality of western flower thrips at lower concentrations of Aa. Strawberry fruit, western flower thrips and two-spotted spider mites were also exposed to multiple applications of Aa over time. Strawberry fruit exposed to low concentrations of Aa in repeated doses showed higher tolerance than fruit exposed to the same dose as a single exposure. While repeated exposure to 1 or 2% Aa resulted in greater pest mortality than a single exposure to 1 or 2% Aa, mortality was significantly lower with repeated applications of low doses as compared with a single application of the accumulated dose (1, 1, 1 Aa vs. 3% Aa). None of the treatments resulted in complete control of either target pest. # 2002 Elsevier Science B.V. All rights reserved.

New Species and Combinations in Larnax (Solanaceae)

Based on phylogenies generated using morphological and molecular data, Deprea glabra and D. sylvarum are transferred to Larnax, and a new subspecies, L. sylvarum subsp. novogranatensis, is described. Four new species are described and illustrated: Larnax cuyacensis from Peru, similar to L. glabra and L. sylvarum, but with a rotate, fleshier corolla much lighter in color, and a fruiting calyx tightly appressed to the berry; L. grandiflora from Peru, intermediate between L. andersonii and L. sachapapa; L. parviflora from Peru, similar to L. psilophyta of Ecuador, but differing in vegetative and reproductive characters and having the smallest flowers in the genus; and L. darcyana from Colombia, similar to L. subtriflora of Peru, but differing vegetatively and with much shorter, non-branching hairs, a smaller corolla, shorter filaments, and apiculate anthers. Keys are provided for selected genera and for Larnax. In addition, some synonymies are noted.

Analysis of gene promoters for two tomato polygalacturonases expressed in abscission zones and the stigma.

The tomato (Lycopersicon esculentum cv Ailsa Craig) polygalacturonase genes TAPG1 (LYCes;Pga1;2) and TAPG4 (LYCes;Pga1;5) are abundantly expressed in both abscission zones and the pistils of mature flowers. To further investigate the spatial and temporal expression patterns for these genes, the TAPG gene promoters were ligated to beta-glucuronidase (GUS) reporter genes and transformed into tomato. GUS expression with both constructs was similar and entirely consistent with the expression patterns of the native gene transcripts. GUS activity was observed in the weakening abscission zones of the leaf petiole, flower and fruit pedicel, flower corolla, and fruit calyx. In leaf petiole and flower pedicel zones this activity was enhanced by ethylene and inhibited by indole-3-acetic acid. On induction of abscission with ethylene, GUS accumulation was much earlier in TAPG4:GUS than in TAPG1:GUS transformants. Moreover, TAPG4:GUS staining appeared to predominate in the vascular bundles relative to surrounding cortex cells whereas TAPG1:GUS was more evenly distributed across the separation layer. Like the native genes, GUS was also expressed in the stigma. Activity was not apparent in pistils until the flowers had opened and was confined to the stigma and style immediately proximal to it. A minimal promoter construct consisting of a 247-bp 5'-upstream element from TAPG1 was found to be sufficient to direct GUS expression in both abscission zones and the stigma.

Photosynthetic activity of the calyx, green shoulder, pericarp, and locular parenchyma of tomato fruit

Photosynthetic activity of the calyx, green shoulder, pericarp, and locular parenchyma of tomato fruit

Photosynthetic activity of the calyx, green shoulder, pericarp, and locular parenchyma of tomato fruit

Photosynthesis of tomato fruit was studied using green fruit from six heritage cultivars of Lycopersicon esculentum Mill. and one of Lycopersicon pimpinellifolium. Chlorophyll concentrations in the green shoulder, pericarp and locular parenchyma of the fruit were determined and the apparent photosynthetic electron transport activity (ETR) and chlorophyll fluorescence quenching characteristics of these tissues and the calyx were compared. In all cultivars, green shoulder formation, apparent as intense pigmentation of the proximal pericarp shoulder, was positively related to the degree of shading of the fruit during development. Appearing as a photosynthetic adaptive trait for increasing the photoautotrophic capacity of fruit grown under low light, the green shoulder contained 17-57% of the total pericarp chlorophyll content. The pericarp below the green shoulder had lower chlorophyll a+b. At a photon flux density (PFD) of 1200 mol m-2 s-1, different fruit tissues were found to have different levels of ETR. In 'Yellow Pear', the upper surface of the calyx had an ETR of 154 mol m-2 s-1, while the lower surface had an ETR of 88 mol m-2 s-1. On the green shoulder, ETR was 203 mol m-2 s-1, whereas in the pericarp distal to the green shoulder, ETR was 97 mol m-2 s-1. In the locular parenchyma, ETR was 66 mol m-2 s-1. This trend towards a lower ETR in distal and internal fruit tissues appeared to indicate a shift towards a more shade-type photosynthesis. Concomitant with this shift were changes in chlorophyll fluorescence quenching characteristics. Generally when tissues displayed reduced levels of ETR they also displayed a faster decrease in the photochemical quenching coefficient qp and a more rapid diversion of absorbed photon energy to non-photosynthetic activity found in the calyx, green shoulder, pericarp, and locular parenchyma suggest that all of these tissues have significant roles in CO2 scavenging and the provision of carbon assimilates. The potential role of fruit photosynthesis in influencing the fruit acid to sugar ratio and hence fruit quality is discussed.