Commercial Harvest Time Research Articles

Changes in the cell walls on fruit skin of Beurré D´Anjou pears (Pyrus communis L.) associated with sunburn injury

• Sunburn reduced cuticular microcrack area and skin thickness, and increased cell wall thickness. • Neutral sugars (NS) content increased in two pectin fractions (WSP and CSP) in sunburn skin. • Hemicellulose and lignin contents increased in sunburn skin. • The expression of Exp and XTH genes increased in response to sunburn. The purpose of this work was to evaluate the effects of sunburn on pear fruit skin at the structural, biochemical, and molecular levels. Pears ( Pyrus communis L.) cv. Beurré D'Anjou were collected at the official commercial harvest time and classified into three groups based on levels of sublethal sunburn: no sunburn (S0), mild sunburn (S1), and moderate sunburn (S2). Skin anatomy was characterized by SEM imaging, cell wall components were quantified by spectrophotometric techniques, and the expression of different genes related to cell wall remodeling was measured in S0, S1, and S2 tissues. Sun-damaged skin cells had reduced size and thickened walls. In the cuticular surface, a reduction of microcracking area, correlated with the intensity of the damage, was further noted. Cell wall fractionation revealed changes in the distribution of neutral sugars (NS) following sunburn, although no differences in uronic acid (UA) content were observed in the different pectin fractions. Hemicellulose and lignin contents were significantly ( P <0.05) increased in sun-damaged tissues. Expression levels of genes encoding polygalacturonase (PcPG2), β-galactosidase (PcGAL2 and PcGAL4), xyloglucan endotransglycosylase (PcXET), and expansin (PCExp1) were increased in the skin of sun-damaged (S1 and S2) fruit. These results indicate that sunburn alters the anatomy and cell wall structure and composition of pear fruit skin, and stimulates different mechanisms involved in the acquisition of stress tolerance.

Effects of different calcium oxide dipping concentrations in aroma profiles of pink lady apple cultivar during cold-storage

Objective: The aim of this research was to assess the profile of volatile compounds changes during the cold storage in ‘Pink Lady’ apples. Material and Methods: Six-year-old Cripps Pink (Pink Lady) fruits of apple trees grafted onto M9 rootstock were used as a plant material for this study. The trees were in a commercial orchard in Çanakkale-Turkey. Fruits were carefully picked up by hand at the commercial harvesting time. The fruits were dipped into calcium oxide solutions (concentrations of 2 and 4%) during three minutes. Control fruits were exposed to distilled water. Fruits were stored at 0° C and 90% relative humidity for 6 months. The aroma profiles of apples determined by GC/MS (Gas Chromatography/Mass Spectrometry) analysis followed by liquid-liquid extraction. Stored fruits were analyzed for their volatile contents at the 2nd, 4th and 6th months. Results: Fresh fruits at harvest period contained 15 volatile compounds in total. However, higher levels of aroma volatile compounds were detected in 6 months of cold storage. According to the chromatography results, control fruits had 24 volatile compounds, 2% CaO treated fruits had 25 volatiles and 4% CaO treated fruits had 27 volatile compounds at the end of the 6 months of cold storage. Apples at the initial stage produced an abundance of hexyl acetate (4.56%), butyl acetate (3.83%), and hexyl hexanoate (1.68%), which confer typical apple aroma characteristics. Mostly, ester production exhibited a fairly broad peak, declining as fruit aged. Isobutyric acid, allyl ester (initial 0.55%) was lower at the beginning of the storage compare to the end of storage (control fruits 0.06%, 2%CaO 0.13%, 4% CaO 0.20%). Conclusion: CaO applications especially 4% concentration had deformation effect on epidermal layer cells on fruit surface. As a result, CaO applications had a significant effect on aroma enhancement in Pink Lady apples during cold storage.

Comparison of fruit maturation and quality of ‘Gala’ apple strains at harvest and after storage

Abstract Strains of ‘Gala’ apples with highly red-colored skins have been planted in new orchards based on consumer interest and financial returns to the producers. The effect of somatic mutation may not be limited to change in fruit skin appearance. In this study, six ‘Gala’ strains were compared regarding fruit maturity and quality attributes at commercial harvest time and after 210 days in controlled atmosphere cold storage plus seven days shelf-life. Experimental orchards were established in three regions and fruit assessed over four seasons. The fruit skin red color area was highest in ‘Baigent’ and ‘Galaxy’, and lowest in ‘Royal Gala’ and ‘Imperial Gala’. Fruit of ‘Maxi Gala’ and ‘Gala Real’ had intermediate skin coloration among the six strains. There was no difference among the strains regarding the fruit weight, starch index, flesh firmness, soluble solid content (SSC), and titratable acidity (TA) at harvest, and flesh firmness, SSC and TA after storage. Fruit of the six ‘Gala’ strains were equally affected by physiological disorders (flesh browning, fruit cracking, calcium deficiency disorders and shrivel) and fungal diseases (external decay, core rot and Glomerella cingulata spot) during storage, indicating that they have similar storability. Only ‘Imperial Gala’ and ‘Royal Gala’ exhibited superficial scald, an unusual disorder for ‘Gala’ cultivar. Harvest management and potential economic impacts of highly red colored fruit of ‘Gala’ strains are discussed.

Girdling alters carbohydrate allocation to increase fruit size and advance harvest in tomato production

This study aimed to examine the effects of girdling on tomato (Solanum lycopersicum L.) plant growth and fruit development, and identify appropriate girdling time on tomato. Girdling was carried out on tomato main stems at four different girdling time: 0 days after anthesis of the last truss (0 DAA), 7 DAA, 14 DAA, and 21 DAA, respectively. Tomato plants that were not treated with girdling served as the control. Girdling altered carbohydrate allocation to different organs. With more carbohydrates partitioned to fruits, girdling significantly increased the fruit weight and yield, and advanced the commercial harvest time by approximately 10 days in comparison to the control. Due to a lack of carbohydrate supply, root biomass and carbohydrate concentration reduced in the girdled plants. No evident sink feedback inhibition of photosynthesis was observed in leaves after girdling. Considering plant growth and fruit development, the appropriate girdling time was approximately 2–3 weeks after anthesis of the last truss. Our results have demonstrated that the application of girdling on tomato plants can increase fruit size and accelerate fruit development, which provides an effective approach to regulate carbohydrate partitioning in tomato production.

Changes in Absolute Contents of Compounds Affecting the Taste and Nutritional Properties of the Flesh of Three Plum Species Throughout Development.

The characteristics of plum fruits of three different species were investigated throughout their development (including over-ripening). The content of primary and secondary metabolites was expressed as amount per gram DW (dry weight) and per fruit in order to obtain information about the balance between their synthesis and dissimilation at different stages of fruit development. In all the plums, during the first stages of development, glucose was the most abundant sugar, whereas sucrose increased during ripening. There was no decrease in malate content per fruit before the commercial harvesting time of any of the plums, whereas a decrease was observed during over-ripening. In general, both the total phenol content and the contents of individual phenols in the flesh expressed on gram DW decreased throughout development, whereas their content per fruit increased, indicating that these decreases were due to a dilution effect arising from the expansion of the flesh. During the development of the flesh, the increase in the contents of the investigated metabolites per fruit shows that there was no net dissimilation of malate up to commercial harvest and of phenols throughout fruit development. Good correlations between the content of phenols to antioxidant activity were found. Shiro flesh, during the last part of fruit development, had lower total carbohydrate and polyphenol contents, lower antioxidant activities, and a higher malate content than the flesh of the other two genotypes.

Varietal Change Dominates Adoption of Technology in Spanish Citrus Production

After describing the technology adopted and its influence on production and yield, the importance of varietal change, which is essential to meet demand, is underscored. The choice of a variety by growers depends on the expected price it will fetch along with the commercial and crop characteristics and the quality. Survival of a variety in the marketplace depends on the performance as expected and on the existence of other more competitive varieties. First, in Spanish citrus farming, the navel group predominate, with 41.10% of orange production, in which the main varieties are “Navelina” and “Lanelate.” The group of late white oranges is also important. The mandarin orange group includes clementines and mandarin hybrids; lemons also feature prominently. In sweet oranges, the navel group and late white group has often been renewed with varieties from the same group. In very early clementines varieties, the survival of which is usually short, the supply of new varieties is excessive. Because of its commercial characteristics and harvesting time, the group with the highest expansion possibilities are the mandarin hybrids which are in demand by hypermarkets. In the introduction of varieties, in recent years we have seen varietal clubs being established, with area control of each variety and very strict rules on cultivation and marketing.

Carotenoids accumulation and carotenoids biosynthesis gene expression during fruit development in pulp of Tubtim-Siam pummelo fruit

Red pulp color of Tubtim-Siam pummelo (Citrus maxima Burm.) is a distinct specific characteristic, which is the preferred in the international market. This present study aimed to determine (1) the influence of tree age on carotenoid accumulation during fruit development, and (2) the carotenoid profile and related biosynthesis gene expression in “Tubtim siam” Pummelo fruit. Fruit were selected randomly from all directions of the tree at different stages of fruit development during the months of June, that is 3 months after fruit setting (3MAFS) to October (7MAFS). The carotenoid profile in the fruit pulp observed include lycopene, β-carotene, zeaxanthin and lutein. From breaker stage to commercial harvesting time, the 8-year old tree fruit observed a significantly higher ration of lycopene, β -carotene, total carotenoid concentrations and higher a* value compared to fruit in 12-year old tree. The expression of carotenoid biosynthesis genes profile in pulp of 8-year old tree fruit revealed the up-regulation of CsPSY, CsZDS and CsZEP gene expression during development and down-regulation of CsβLCY, CsβCHX and CsεCHX gene expression after breaker stage (5MAFS); that appeared to be a key factor triggering lycopene accumulation because these were the key genes expressed during fruit development.

Starch structure in developing kiwifruit

Starch is the major component of kiwifruit at the time of commercial harvesting. The structural changes of starches from 2 kiwifruit varieties (Hayward and Gold3) at different growing stages up to commercial harvesting time were studied. During the fruit growth, the starch content (dry weight basis) increased from ~2% to 46% (Hayward) and 58% (Gold3) and the starch granules enlarged from 4 to 10 μm. The polymorph type of the starches remained as B-type and the amylose contents (AC) levelled off (~10–12%, Hayward) or increased (~15 to 19%, Gold3) throughout the fruit developing. The external and internal structures of amylopectins remained similar as the starch granules enlarged in expanding kiwifruit, suggesting a homogeneous molecular structure from the centre towards the periphery of a kiwifruit starch granule. This is the first report to provide the structural information on B-type starch granules in developing fruit. The results of the structural changes shared similarity as well as differences with other types of the starches in developing crops including kidney bean and various cereals. The comparative analysis suggests that the evolution of amylopectin structure in developing crops largely depends on the botanical source, and the dynamics of AC appeared to be independent of that of amylopectin structure.

Modeling and analysis in a prey–predator system with commercial harvesting and double time delays

A differential-algebraic prey–predator system with commercial harvesting on predator is proposed, where maturation delay for prey and gestation delay for predator are considered. Since commercial harvesting is dynamically influenced by variation of economic interest, we will investigate combined dynamic effects of double time delays and economic interest on population dynamics. Positivity of solutions and uniform persistence of system are studied. In the absence of time delay, by taking economic interest as bifurcation parameter, existence of singularity induced bifurcation is investigated based on differential-algebraic system theory. State feedback controllers are designed to eliminate singularity induced bifurcation and stabilize the proposed system around corresponding interior equilibrium. In the presence of double time delays, by analyzing associated characteristic transcendental equation, it is found that interior equilibrium loses local stability when double time delays cross corresponding critical values. According to Hopf bifurcation theorem for functional differential equation, existence of Hopf bifurcation is investigated as local stability switches. Based on normal form theory and center manifold theorem, directions of Hopf bifurcation and stability of the bifurcating periodic solutions are studied. Numerical simulations are carried out to show consistency with theoretical analysis.

Ethylene Emission of Apples Treated with 1-Methylcyclopropene During Storage

Abstract The effect of post-harvest application of 1-methylcyclopropene (1-MCP) on ethylene emission in early-winter apple (cv. ‘Calville’), winter (‘Gloster’, ‘Golden Delicious’ and ‘Jonagold’), and late-winter cultivars (‘Granny Smith’, ‘Idared’ and ‘Reinette Simirenko’) w as investigated. The fruits were picked at a commercial harvest time and half of them were treated with 1-MCP (‘SmartFresh™’ 0.068 gm-3) for 24 h at 5 °C. Then both groups of apples were placed in a common storage at the temperature of 2 °C. The intensity of fruit ethylene emission (rate of ethylene production) was measured and 1 -MCP inhibition index was calculated. During storage, activity of ethylene emission by control apples of ‘Calville’ and ‘Golden Delicious’ showed typical climacteric pattern, while the intensity of ethylene emission of apples of other cultivars only increased gradually. The change of ethylene activity of early-winter apple cv. ‘Calville’ and winter cv. ‘Jonagold’, both treated with 1-MCP after harvest, had exponential character, especially actively increasing after 3 months of storage. At the same time ethylene emission of 1 -MCP treated fruits of other cultivars changed steadily to a low level and was effectively suppressed during the whole 6-month period of storage in normal atmosphere. The value of inhibition index of fruits treated by 1-MCP confirmed the consistent restoration of the ability to ethylene synthesis and thus to post-harvest ripening of some apples cultivars.

Characterization of a giant-fruit mutant exhibiting fruit-limited polyploidization in pear (Pyrus communis L.)

Fruit size is one of the most important traits in fruit trees. We found a bud sport mutant bearing giant fruits of pear in an orchard in Yamagata prefecture, Japan. The fruit weight of this mutant was more than twice that of an original cultivar ‘La France’. The size of the receptacle was already larger in the mutant than in the original cultivar at full bloom, and size differences between the mutant and the original cultivar were observed throughout fruit development. Microscopic observation of fruit cortex cells revealed that the size of cells was larger in the mutant than in the original cultivar, and that the number of cells was comparable between the mutant and the original cultivar. Flow cytometric analysis revealed an increase in the number of cells having doubled amounts of DNA (4C cells) in the fruit cortex, but such an increase was not found in leaves, suggesting chimeric polyploidization or endoreduplication in fruits of the mutant. Mutant fruits exhibited significantly higher titratable acidity and lower firmness than those of the original cultivar. These differences were observed from 110 days after full bloom to 165 days (the commercial harvesting time). However, the concentration of soluble solids was not different between the mutant and the original cultivar. There were no significant differences in polyuronide contents between the mutant and the original cultivar fruits, but hemicellulose content in fruits of the mutant was significantly lower than in those of the original cultivar.

Efeito da temperatura e reação de genótipos de quiabeiro ao mofo branco

O quiabeiro é suscetível a várias doenças que podem causar prejuízos ao agricultor, caso não sejam manejadas. Objetivaram-se avaliar o efeito da temperatura e a reação de genótipos de quiabeiro ao mofo branco. Plantas de 30 dias inoculadas na região do colo, com e sem ferimento, com dois isolados de Sclerotinia sclerotiorum, foram mantidas por duas semanas nas temperaturas de 15; 20; 25; 30 ou 35ºC. Quatorze genótipos de quiabeiro com um e dois meses de emergência, assim como frutos no ponto de colheita comercial tiveram seus comportamentos avaliados quanto à doença. Avaliaram-se a incidência de plantas com tombamento ou mortas e o comprimento da lesão nos frutos inoculados. A doença foi favorecida por temperaturas entre 15 e 20ºC e, de maneira geral, não foram observadas diferenças entre os isolados e influência do ferimento na ocorrência da doença. Não foram encontrados genótipos de quiabeiro resistentes ao mofo branco, pois todos apresentaram incidência superior a 30% de plantas mortas, sendo as plantas mais novas mais suscetíveis, e comprimento de lesão nos frutos &gt;6,0 cm. Entretanto, diferenças de suscetibilidade entre os genótipos foram observadas em plantas de 30 e de 60 dias e podem ser informações úteis aos produtores para escolha de cultivares em clima ameno, assim como ser exploradas em programas de melhoramento.

The Role of ABA in the Maturation and Postharvest Life of a Nonclimacteric Sweet Cherry Fruit

The purpose of this study was to investigate the role of abscisic acid (ABA) in the pre- and postharvest maturation of the nonclimacteric sweet cherry. It was found that ABA content increased rapidly at the straw-colored stage and reached its highest level 4 days before commercial harvest time. The increase in ABA level was paralleled by an increase in the expression of a gene involved in ABA synthesis [9-cis-epoxycarotenoid dioxygenase (PacNCED1)]. Well before the ABA increase, the expression of a gene involved in ABA catabolism (PacCYP707A2) was downregulated. During the straw-colored stage, the application of exogenous ABA induced ABA accumulation, anthocyanin biosynthesis, and an increase in the maturity index (SSC/TA), thereby promoting fruit ripening. ABA treatment stimulated the expression of PacNCED1 and of genes involved in anthocyanin biosynthesis (PacCHS, PacF3H, PacCHI, PacDFR, and PacUFGT). The application of NiCl2 inhibited the release of ethylene and the expression of PacACO1 encoded 1-aminocyclopropane-1-carboxylic acid oxidase, of which the effect on fruit ripening was opposite that of ABA. Ethephon and nordihydroguaiaretic acid treatments, however, had no effect on fruit ripening. For postharvest fruit, the pedicel was a major route for water loss, and dehydration induced the transcription of PacNCED1 and the accumulation of ABA. Followed by ethylene release, the start of postharvest fruit senescence is triggered. In conclusion, endogenous ABA triggered the ripening of fruit via the modulation of ripening-related metabolism pathways such as anthocyanin accumulation. ABA also induced postharvest fruit senescence through stimulation of ethylene release in cherry fruit.

NIRS technology for fast authentication of green asparagus grown under organic and conventional production systems

This study sought to evaluate the ability of near-infrared reflectance spectroscopy (NIRS) to classify intact green asparagus as a function of growing method (organic vs. conventional) during postharvest refrigerated storage, and as a function of harvest month and postharvest cold storage duration. It also sought to identify the portion of the spear best suited for this purpose. A total of 300 green asparagus spears (Asparagus officinalis L., cv ‘Grande’), were sampled after 7, 14, 21 and 28 d of refrigerated storage (2°C, 95% RH) and at commercial harvest time. Three commercially available spectrophotometers were evaluated for this purpose: a scanning monochromator (scanning range 400–2500nm), a diode-array Vis/NIR spectrophotometer (range 400–1700nm) and a handheld MEMS spectrophotometer (range 1600–2400nm). Models constructed using partial least squares 2-discriminant analysis (PLS2-DA) correctly classified 91% of samples by growing method using the diode array instrument, between 86% and 91% using the scanning monochromator and between 82% and 84% using the handheld spectrometer. The tip and the middle portion of the spear proved to be the most suitable for this purpose employing the MEMS instrument. Using similar models, the diode array instrument correctly classified 100% of samples by harvest month, compared with between 97% and 98% using the scanning monochromator and between 87% and 96% using the handheld instrument. Models also correctly classified between 66% and 97% of samples by postharvest storage time, depending on the instrument used. The results indicate good performance of the prediction models, particularly for predicting harvest month and growing method, determination of the latter being of considerable importance for the authentication of organic asparagus at industrial level.

Instrumental Textural Properties of Mango (cv Nam Doc Mai) at Commercial Harvesting Time

Mango fruit (Mangifera indica L., cv Nam Doc Mai number 4) of three different sizes, were evaluated for their instrumental texture properties, in accordance with the exporter requirements at commercial harvesting time. The size classification of mangoes was determined by the mass of the fruit. The large size weighed more than 351 g, the medium size 330–350 g, and the small size 260–329 g. The results of deformation at a force of 20 N, energy of absorption from a compression test and the average hardness from puncture tests varied for the different sizes. The large size showed firmer and more elastic in relation to the compression force, as well as the hardest and most rigid in response to the puncture force. The peel and flesh strengths of large, medium, and small sizes at the commercial harvesting date did not differ with bio-yield force, which indicated that the strength of the flesh under the peel was very close to the rupture force, which indicated the strength of peel. Examples of the applications of these properties for postharvest handling are described.

Postharvest shelf-life discrimination of nectarines produced under different irrigation strategies using NIR-spectroscopy

Quick assessment of storage time in fruits is important for both growers and consumers due to the fresh fruit market is becoming increasingly demanding with regard to product quality. This study sought to evaluate the ability of near-infrared reflectance spectroscopy (NIRS) to classify intact nectarines in post-harvest storage, as a function of pre-harvest irrigation strategies applied and post-harvest cold storage duration. A total of 220 nectarine fruits ( Prunus persica (L.) Batsch cv. ‘Sweet Lady’) were sampled after 7, 14, 21 and 28 days of refrigerated storage (0 °C, 95% RH) and at commercial harvest time. Two commercially-available spectrophotometers were evaluated for this purpose: a handheld MEMS spectrophotometer of 1600–2400 nm and a diode-array Vis/NIR spectrophotometer of 400–1700 nm. Models developed using partial least squares 2-discriminant analysis (PLS2-DA) correctly classified between 86 and 96% of samples by post-harvest storage time using the handheld instrument, and between 66 and 89% in the case of the diode-array spectrophotometer. Classification models based on pre-harvest irrigation treatment classified 57–84% of the samples correctly, due to the similarity in physical–chemical properties of fruits in both irrigation strategies. These results showed that NIRS could be used to monitor changes in nectarine quality parameters during pre- and post-harvest as an essential tool for decision-making both in-field and on-line.

FRUIT FLESH FIRMNESS IN TWO PLUM CULTIVARS: COMPARISON OF TWO PENETROMETERS

Plums (Prunus domestica L.) of cultivars 'Opal' and 'Victoria' were sampled at commercial harvest time in the experimental field at Bioforsk Ullensvang, south-western Norway. Samples were taken from the south-facing side of trees 1-1.5 m above ground, brought to the laboratory and graded into three different degrees of fruit development (1 = less coloured, 3 = best coloured) based on a combination of their surface ground and blush colour. Colour (LDF), weight, size and soluble solids content (TSS) were measured in representative fruit samples. Fruit flesh firmnesses were measured using two different penetrometers; Durofel (Copa-Technologie S.A., Paris, France), a hand-held shore-type penetrometer equipped with a plunger connected to a sensor that measures specifically the elasticity of the outer fruit skin when the plunger is pressed against the fruit, and PNR 10 (Sommer & Runge KG, Berlin, Germany) equipped with a plunger penetrating into the fruit surface by means of its own weight (115 g) over a 15 s period. Both cultivars showed highly significant differences in amount of colour, but only minor differences in fruit weight and size between the three groups. TSS increased significantly from group 1 to group 3, for 'Opal' more distinct than for 'Victoria'. The resulting firmness measurements were compared by means of regression analysis. In 'Opal' group 2 and 3 and in all three groups of 'Victoria' the measures from the two penetrometer types fitted significantly to a regression line; a quadratic better than a linear one, indicating that the two penetrometers measured slightly different properties of the fruit skin and outer fruit flesh.

Influence of within-tree and environmental factors on fruit quality of cactus pear (Opuntia ficus-indica) in Italy

Introduction . Opuntia ficus-indica fruit quality was studied, in the main sites for cactus pear cultivation in Italy, with the ultimate goal of understanding the main sources of variability and increasing crop value. Materials and methods. A first study was carried out in 2006 on mature Opuntia ficus-indica trees, cvs. Gialla and Rossa, grown in ten commercial orchards located in the main sites for their cultivation in Italy. Trees were managed to produce an out-of-season crop in October, through the removal of the spring flush at bloom time, during the first week of June. Trees had a similar crop [(52 ± 10) kg of fruits·tree–1 ], and no more than six fruits were left on each of the fruiting cladodes. At commercial harvest time, indicated by the peel colour breakage, 75 fruits in each orchard and 750 fruits for each site were picked, analysed and evaluated by a consumer panel. A second experiment was carried out in 2006 on 8-year-old O. ficus-indica trees, cv. Gialla, grown in a commercial orchard. Within-tree factors, such as fruit position within the canopy, number of fruits per tree and per cladode, and cladode dry weight were studied. Results and discussion. Fruit weight, shape and total soluble solid content significantly changed with the environmental conditions, i.e., site and altitude, while flesh percent, pH and total titratable acidity did not. Cultivars had a significant influence only on fruit weight and seed content. Fruit weight changed greatly within the tree, while total soluble solid content and flesh percent variability was much reduced. Fruit weight decreased with fruit number per tree and both fruit weight and total soluble solid content decreased with more than six fruits per cladode. Light interception and cladode dry weight were the main sources of fruit dry weight variability and sugar content, while cladode surface area was poorly related to fruit quality. The role of cultivars in determining fruit quality did not change with site and, moreover, the sensory analysis was unable to discriminate for cultivar and environment.

Endoreduplication in cucumber (Cucumis sativus) seeds during development, after processing and storage, and during germination

AbstractFlow cytometry was used to study endoreduplication in developing, stored and germinating seeds of cucumber (Cucumis sativus). Fruits growing in a commercial seed production field were collected every 7 days, starting 14 days after pollination (DAP) up to 63 DAP (commercial harvest time). Seeds were isolated and the proportion of nuclei with different DNA contents in the whole seeds and in the embryos was analysed. Germination capacity of fresh and dried seeds at 25°C was established. In addition, the same analyses were performed on the seeds after processing (fermentation, drying and cleaning), following 1 and 2 years of storage, and after imbibition for 3, 6 and 12 h. In the young developing seeds, endoreduplication up to 128C occurred but this decreased to 8C by maturity. The proportion of endosperm nuclei was the highest at 21 DAP (30%) and then decreased to below 14% at harvest and 8% after processing. In the mature processed seeds, the majority of embryo nuclei (about 80%) contained 2C DNA; however, about 2% of endoreduplicated (8C) nuclei were still present. Seeds did not show any germination capacity up to 21 DAP; then it gradually increased to reach 100% as early as 49 DAP, 2 weeks before commercial harvest time. The relationship between seed maturity, germination and cell cycle status is discussed. The mean C‐value of the seed cells as well as the (4C + 8C + 16C)/2C ratio are recommended as markers of cucumber seed maturity and the advancement of germination/priming (the stage of germination sensu stricto).

Eficácia do tratamento de avg no controle da queda e maturação dos frutos de maçã, cultivar imperial gala

O objetivo deste trabalho foi avaliar o efeito de concentrações e épocas de aplicação do AVG no controle da queda pré-colheita, no retardamento da maturação e na qualidade de maçãs cv. Imperial Gala. Testaram-se 4 épocas de aplicação (45; 30; 15 e 7 Dias Antes do início do Ponto de Colheita presumido da testemunha - DAPC) e 4 concentrações (0; 90; 124 e 62 + 62 g.ha-1), em dois anos, 2003 e 2004. A degradação do amido, a queda da firmeza da polpa, o aumento do teor de sólidos solúveis totais (SST) e as mudanças da cor dos frutos tratados com AVG foram retardados em relação aos frutos não-tratados. Conforme esperado, AVG retardou o ponto de colheita comercial em 7 a 16 dias e a queda pré-colheita dos frutos em até 30 dias. Os efeitos do AVG no retardamento da maturação foram dependentes da concentração e da época de aplicação. Aplicações de AVG mais próximas do ponto de colheita comercial, 7 DAPC, foram mais efetivas no controle de queda de frutos pré-colheita e no retardamento da perda de firmeza do que aplicações mais precoces (30 ou 45 DAPC). Doses de 124 e 90 g.ha-1 de AVG são igualmente efetivas quando aplicadas 7 ou 15 dias antes do ponto de colheita comercial. O retardamento da maturação e o controle da queda pré-colheita foi tanto maior quanto maior a dose e mais próximo do ponto de colheita comercial foi a aplicação do AVG. Os resultados demonstram que é possível manejar a intensidade de retardamento da colheita alterando a época de aplicação entre 7 e 30 DAPC e a dose de AVG entre 90 a 124 g.ha-1.