primordia under different thermal regimes. ATP/ADP ratio may influence the primordia capacity to ... more primordia under different thermal regimes. ATP/ADP ratio may influence the primordia capacity to compete with neighbouring tissues. To evaluate variations of the ATP/ADP ratio in peach primordia, peach (Prunus persica cv. flamecrest) trees were exposed to three different thermal regimes: T1: 3 °C for 34 days + 8 °C for 26 days + 10 °C for 30 days; T2: 3 °C for 60 days + 10 °C for 30 days; T3: 18 °C for 90 days. Endodormancy and short-distance paradormancy were broken after 34 days according to the 'single-node cutting' test. In T1 vegetative primordia, ATP/ADP ratio increased 14% between days 30 and 60, and additional 75% between days 60 and 90. T2 vegetative primordia showed an ATP/ADP increase of 64% between days 30 and 60. Endodormancy and short distance paradormancy release appears as a prerequisite for an increase in ATP/ADP ratio but temperature following the onset of endodormancy release affects the rate of ATP/ADP upsurge. ATP/ADP ratio increased 290% throughout the experiment in T1 floral primordia, and 306% in T2 floral primordia. In T1 and T2, ATP/ADP levels were higher in vegetative primordia but increased at a higher rate in floral primordia. ATP/ADP ratio did not change in T3 vegetative primordia and decreased in T3 floral primordia throughout the experiment. This may explain the metabolic incapacity of cold-deprived primordia to develop. We conclude that the ATP/ADP ratio may be utilized to determine the growing capacity of vegetative and floral primordia in peach trees.
Purpose of the review: Although the majority of 1-methylcyclopropene (1-MCP) research and develop... more Purpose of the review: Although the majority of 1-methylcyclopropene (1-MCP) research and development has been on apple, an increasingly significant body of work is accumulating for a wide variety of fruit species. The objective of this paper is to create a snapshot of the current state-of-the-art, provide an estimate of the potential benefits for the use of 1-MCP in tree fruit crops where development is still in progress, and evaluate factors that can influence successful application. Importantly, this review summarises the perspectives of an international panel of recognised experts on the potential benefits of 1-MCP on a crop-by-crop basis. Main findings: The use of 1-MCP for improving the storability and quality of horticultural products is truly global. Currently, 27 countries use 1-MCP as the formulation SmartFresh™ on 25 different commodities, 18 of which are tree fruits. The survey indicates that postharvest experts anticipate "good, very good or excellent potential benefit" for 15 of the current 18 registrations, with apple and persimmon ranking highest. Little or no potential for benefit is envisioned for most of the fruit crops for which no registrations currently exist. Achieving consistent results, especially among those commodities not as well suited to 1-MCP use as apple fruit, will be a function of cultivar choice, preharvest factors, fruit maturity, treatment conditions, pathology, and interaction of 1-MCP and the postharvest environment. The findings illustrate that many aspects of the influence of 1-MCP on various commodities remain to be clarified before 1-MCP is fully adopted on a commercial scale. Directions for future research: There is no doubt that the commercial impact of 1-MCP will increase as further research is carried out. Nevertheless, ample investigation is needed to determine the influence of preharvest factors and harvest conditions on fruit response to 1-MCP, as well as its influence in any disease-control program. 1-MCP sprayable formulations applied during the growing season have potential as an orchard management tool to ameliorate preharvest problems (eg, abscission) in addition to improving postharvest fruit quality. Testing the effectiveness of 1-MCP on new crops as a complement to low temperature storage and modified atmospheres must be carried out to evaluate the feasibility and limitations of these technologies on a commercial scale. The influence of 1-MCP on consumer acceptance does not seem to be a problem for apples, but could represent a stumbling block for other tree fruit crops and merits further research.
Different dormancy-breaking pretreatments were assessed in order to improve germination of caper ... more Different dormancy-breaking pretreatments were assessed in order to improve germination of caper ( Cuppuris spinosa L. ) seeds. High germination percentages were obtained using concentrated sulfuric acid, followed by either a 90&n soaking procedure in a 100 ppm gibberellin (GA,,+7) solution, or adding 0.2% potassium nitrate to the test substrate. Results obtained by means of a surgical treatment clearly suggest that the dormancy of the caper seed is imposed by its covering structures. * Corresponding author. 0304-4238/95/$09.50 0 1995 Elsevier Science B.V. All rights reserved SSDIO304-4238(95)00779-2
Sweet cherry (Prunus avium L.) is a fruit of increasing economic importance though it is less sig... more Sweet cherry (Prunus avium L.) is a fruit of increasing economic importance though it is less significant than other stone fruit species such as peach. Cherry has received little attention concerning nitrogen (N) uptake and dynamics in mature trees. The aim of this work was to determine N uptake and partitioning as influenced by the timing of fertilizer application in 7-year-old sweet cherry trees cultivated in a cold region (Los Antiguos, Santa Cruz, Argentina; 71 • 38 W, 46 • 32 S). Nitrogen (95 kg ha −1 ) was applied as ammonium nitrate to a soil with 'Bing' sweet cherry trees grafted onto Prunus mahaleb rootstocks. Fertilization was split into two equal applications per treatment, involving either the commercial fertilizer ammonium nitrate or the same fertilizer labelled with 15 N isotope (10% atom.). Treatments consisted of one early spring (full bloom, October 2005) or one summer (late January 2006, 15 days after harvest) application of 15 N ammonium nitrate to three replicate trees. Fruit were harvested in early January and leaves were collected at both full canopy and leaf fall. All trees were excavated in winter (August, 2006). Trees were partitioned into their components: trunk, branches (current-season shoots, 1-year-old and over-1-year-old branches), buds of the same age, small roots (less than 1 mm thick), large roots, leaves (sampled in February and April), and fruit (collected at harvest). Those components were dried and analysed for total N and 15 N content. Total N per tree and N content derived from the fertilizer did not differ between treatments. Summer postharvest 15 N application partitioned not only to structural components (trunk and roots) but also to buds and leaves. Uptake efficiency was significantly (p = 0.0113) higher in the spring than in the summer application (65.7% vs. 37.44%). Nevertheless, 52.5% of N applied in spring was lost due to harvest and summer pruning. This emphasizes the importance of the postharvest N fertilization which increases N accumulation in both reserve organs and buds though, according to our data, it is less efficiently used. The extent of nitrogen uptake, efficiency of use and partitioning in the following growing seasons are still open questions that deserve further research.
Wooden bin-stored 'Bartlett' pears (Pyrus communis L.) were hydrocooled (HC) or forced-air cooled... more Wooden bin-stored 'Bartlett' pears (Pyrus communis L.) were hydrocooled (HC) or forced-air cooled (FAC) and immediately treated or not with 1-methylcyclopropene (1-MCP) for 24 h. 1-MCP gas concentrations used were 0, 0.3 or 0.6 L L −1 (called 0, 0.3 and 0.6, respectively). Fruit were subsequently kept at 20 • C for 20 d or stored at −0.5 • C and 95% RH for 60, 90, 120 or 150 d. After cold storage, fruit were kept at 20 • C for up to 16 d for further ripening. In another experiment, pears stored in wooden bins (W) or plastic bins (P) were all hydrocooled, treated or not with 0.5 L L −1 1-MCP (called 0.5 and 0, respectively), stored at −0.5 • C and 95% RH for 0, 30, 60, 90 or 120 d, and transferred to 20 • C for further ripening. In FAC pears, increasing 1-MCP concentrations usually resulted in delayed increases in ethylene production and lower ethylene production rates, as well as delayed softening. In contrast, HC-0.3 pear firmness did not differ from that of HC-0 fruit after cold storage. Generally, HC-0.3 pears displayed higher ethylene production and lower firmness values than FAC-0.3 pears after a 7-d exposure to 20 • C, regardless the length of cold storage. FAC-0.6 pears always showed lower ethylene production rates and higher flesh firmness values than HC-0.6 fruit. Soluble solids concentration was not consistently affected by 1-MCP. FAC-0.3 and HC-0.6 fruit showed higher titratable acidity values than HC-0 fruit after 0, 60, 120 and 150 d of cold storage plus 7 d at 20 • C. Effectiveness of 1-MCP treatments on HC pears was influenced by the bin material; P-0.5 pears were firmer than W-0.5 pears after 7 d at 20 • C, regardless the length of the cold storage. HC-0.5 fruit exposed to −0.5 • C for 90 d reached eating quality (firmness ≤23 N) by day 7 if placed in W, and by day 21 when stored in P. Results and previous evidence suggest that wet wooden bin material may represent a major though unpredictable source of 1-MCP sorption that could bind a significant percentage of the 1-MCP applied. When used at relatively low doses 1-MCP partial removal by wet wooden bins can compromise the application effectiveness for controlling ethylene action.
The terms 'soft fruit' have been used to refer to different commodities including strawberries, b... more The terms 'soft fruit' have been used to refer to different commodities including strawberries, blueberries and several species of the genus Rubus. Most work in 'soft fruit' ripening regulation has been done on strawberry. Auxin has been shown to be a repressor of several ripening-associated genes which led to hypothesize that reduction in auxin levels in the receptacle could activate those genes. Despite that, some evidence suggest that that is only part of the story and that other factors are also involved in the regulation of 'soft fruits' ripening process. Softening is one of the most dramatic changes observed in 'soft fruit' ripening. Early reports on strawberry stated that the average molecular size of hemicelluloses greatly declines during ripening. In contrast, later work showed that pectin size is reduced while only slight depolymerization occurs in hemicellulosic polymers. Pectin metabolism has recently shown to be a major modification accompanying softening in species of the genus Rubus. Contrarywise, a reduction in glucan content and downshifts in hemicellulose molecular size are the main changes observed in blueberry. Extension of 'soft fruit' postharvest life has been an ongoing challenge. Strategies to reduce 'soft fruit' losses include selection of firmer genotypes and optimum postharvest handling procedures. A single postharvest technique is unlikely to fully control postharvest losses but new tools such as UV radiation, heat treatments or chitosan coatings may be added to the overall management plan (cooling conditions, modified atmospheres) to further delay softening and prevent decay losses. Biotechnology may be useful to address some of the concerns about bramble quality attributes (e.g. increased fruit firmness, improved flavor) and engineered resistance may be a sustainable method to control Botrytis cinerea.
52 Introduction The Prunoideae, a subfamily of Rosaceae, includes several species producing edibl... more 52 Introduction The Prunoideae, a subfamily of Rosaceae, includes several species producing edible drupes with economic importance. In 2001, worldwide annual production of Prunoideae exceeded 28.3 million metric tons, including almost 13.5 million tons of nectarines and peaches (Prunus persica (L.) Batsch), 9 million tons of plums (Prunus domestica L.), 2.7 million tons of apricots (Prunus armeniaca L.), 1.8 million tons of sour and sweet cherries (Prunus cerasus L. and Prunus avium L. respectively) and 1.3 million tons of almonds (Prunus amygdalus Batsch = Prunus dulcis (Miller) D.A. Webb) (Table 1) 1 . Prunus species are characterized by developing only one ovary in which two ovules typically form; one of them degenerates soon after anthesis. The fruit is a drupe where the mature stony endocarp together with the seed forms a propagation unit comparable to a botanical seed surrounded by its protective testa.Breeding practices in Prunus must address the challenges resulting from the...
Abstract A full-length cDNA clone named PsARF/XYL was obtained from Prunus salicina Lindl., and d... more Abstract A full-length cDNA clone named PsARF/XYL was obtained from Prunus salicina Lindl., and determined to encode a putative α-l-arabinofuranosidase/β-d-xylosidase belonging to glycoside hydrolase (GH, EC 3.2.1.-) family 3. Two related PsARF/XYL cDNAs were amplified, one from a fully-spliced transcript (PsARF/XYLa) and another one from an intron-retained transcript (PsARF/XYLb). The protein deduced from PsARF/XYLb is a truncated peptide at C-terminus that conserves the active-site amino acid sequence. High levels of PsARF/XYLa and PsARF/XYLb transcripts are detectable in several plant tissues. PsARF/XYLb transcripts accumulate progressively during the phase of exponential fruit growth but they become barely noticeable during on-tree ripening, or after a 6-h exposure of preclimacteric full-size plums to ethylene. In contrast, PsARF/XYLa is expressed throughout fruit development, and transcript accumulation parallels the climacteric rise in ethylene production during ripening. PsAR...
Preclimacteric European pears (Pyrus communis L. cv. "Bartlett") were untreated or treated with 0... more Preclimacteric European pears (Pyrus communis L. cv. "Bartlett") were untreated or treated with 0.4 l l −1 1-methylcyclopropene (1-MCP) for 10 h at 20 • C and then kept at 20 • C, or stored at 1 • C for 30 or 60 days before transfer to 20 • C. Other lots were treated with 0.4, 0.8, 1.2, or 1.6 l l −1 1-MCP after 30 or 60 days of storage at 1 • C. 1-MCP-treated pears kept at 20 • C had lower ethylene production and slower softening than untreated fruit. Treated fruit were more than 75 N firmer than control fruit after a 6 day storage period. Fruit color changes were also delayed by 1-MCP treatment. However, additional color sorting may be necessary to reduce variability in response of fruit to 1-MCP in commercial situations. 1-MCP-treated fruit had lower total glycosidase (␣and -d-galactosidase, ␣-l-arabinofuranosidase, -d-xylosidase, and -d-glucosidase) activities. When 1-MCP was applied to fruit prior to cold storage (CS) at 1 • C, the synergistic interaction of cold and 1-MCP resulted in an extended postharvest life after transfer to room temperature, with concomitant delayed ethylene and respiratory level increases, retarded color development and retention of firmness. In contrast, application of 0.4-1.6 l l −1 1-MCP after 30 or 60 days of cold storage did not affect most ripening indices. These findings point to the experimental and commercial utility of 1-MCP in "Bartlett" pear postharvest management.
Tomato fruit show physiological disorders when exposed to temperatures at or above 30°C. It has b... more Tomato fruit show physiological disorders when exposed to temperatures at or above 30°C. It has been suggested that the cz-and p-galactosidases ((Y-and /I-Gal), as well as the endop-mannanase could play roles during fruit ripening. Their pattern of activities was followed in detached tomato fruit, and the degree of inhibition of the activity at high temperatures was evaluated. The potential resumption of the enzyme activity when fruits were transferred to a room-temperature environment was also studied. Mature-green fruits were incubated at: (a) 36°C for 2 days, (b) 40°C for 2 days, or (c) 40°C for 2 days +36"C for another 2 days. After heat treatments, fruits were transferred to a 21°C dark environment. Control fruit were stored at 21°C. In the control fruit, activity was higher for a-Gal than for &Gal and revealed slightly increasing patterns toward the red-ripe stage. Endo-jl-mannanase activity was not detected in mature-green tomatoes but appeared at the breaker stage and rose rapidly, reaching constant values at the red-ripe stage. The firmness and enzymatic activities of fruits initially treated at 36°C for 2 days were similar to those of the control group. Galactosidase activity decreased in tomatoes incubated at 40°C for 2 days; and in those whose heat treatment was extended another 2 days at 36°C the aand &Gal reached a minimum of l/S and l/25, respectively, of the initial activity on the fourth day. The activity of the endo-fi-mannanase could be detected only 6 days after the fruit had been transferred to a 21°C environment and increased slowly up to 24% of that attained by the control group. a-Gal showed a low rate of recovery but B-Gal activity recovered after 16 days at 21°C. Results could be associated with an active role of these enzymes on the fruit softening process. * Corresponding author. Fax: +54 (I) 522-8395. 0925-.5214/%/$15.00 Copyright 0 1996 Elsevier Science B.V. All rights reserved HI SO925-5214(96)00014-2 G.O. So-i et al. / Posthamest Biology and Technology 9 (I 996) 49-63
Transient (1 h) treatment of breaker tomatoes (Lycopersicon esculentum Mill. cv. Bonanza) with ex... more Transient (1 h) treatment of breaker tomatoes (Lycopersicon esculentum Mill. cv. Bonanza) with exogenous GA 3 or IAA at a high concentration (20 mM) resulted in a two-to four-fold increase compared with the control in ethylene biosynthesis during a 9-day experiment. This sharp increase in ethylene emission is characteristic of a stress response. Both phytohormones promoted the activity of 1-aminocyclopropane-1-carboxylate synthase that probably accounts for most of the enhanced ethylene synthesis. GA 3 and IAA also stimulated total ␣and -galactosidase and ␣-L-arabinofuranosidase activity but showed some potential to delay ripening parameters, among them, fruit softening, chlorophyll loss, and total carotenoid synthesis. GA 3 -or IAA-treated fruit did not respond to exogenous 100 ppm C 2 H 4 with an increase of autocatalytic ethylene production. Moreover, GA 3 or IAA applied alone showed a faster increase in ethylene biosynthesis than that achieved by exogenous C 2 H 4 . The combination of GA 3 and C 2 H 4 -supplemented atmosphere did not result in synergistic effects on glycosidase activity except for a few cases. IAA-treated fruit exposed to C 2 H 4 -supplemented atmosphere did not promote additional glycosidase activity but rather seemed to have antagonistic effects on -galactosidase during the first few days of the experiment. Glycosidase response to GA 3 and IAA treatments did not correlate with changes in tomato pericarp firmness, thus suggesting that some isoforms may have no role in tomato fruit softening.
Antioxidante en berries y otros frutos y factores que afectan su acumulación. Antioxidants in berries and another fruits, and factors that affect their accumulation
primordia under different thermal regimes. ATP/ADP ratio may influence the primordia capacity to ... more primordia under different thermal regimes. ATP/ADP ratio may influence the primordia capacity to compete with neighbouring tissues. To evaluate variations of the ATP/ADP ratio in peach primordia, peach (Prunus persica cv. flamecrest) trees were exposed to three different thermal regimes: T1: 3 °C for 34 days + 8 °C for 26 days + 10 °C for 30 days; T2: 3 °C for 60 days + 10 °C for 30 days; T3: 18 °C for 90 days. Endodormancy and short-distance paradormancy were broken after 34 days according to the 'single-node cutting' test. In T1 vegetative primordia, ATP/ADP ratio increased 14% between days 30 and 60, and additional 75% between days 60 and 90. T2 vegetative primordia showed an ATP/ADP increase of 64% between days 30 and 60. Endodormancy and short distance paradormancy release appears as a prerequisite for an increase in ATP/ADP ratio but temperature following the onset of endodormancy release affects the rate of ATP/ADP upsurge. ATP/ADP ratio increased 290% throughout the experiment in T1 floral primordia, and 306% in T2 floral primordia. In T1 and T2, ATP/ADP levels were higher in vegetative primordia but increased at a higher rate in floral primordia. ATP/ADP ratio did not change in T3 vegetative primordia and decreased in T3 floral primordia throughout the experiment. This may explain the metabolic incapacity of cold-deprived primordia to develop. We conclude that the ATP/ADP ratio may be utilized to determine the growing capacity of vegetative and floral primordia in peach trees.
Purpose of the review: Although the majority of 1-methylcyclopropene (1-MCP) research and develop... more Purpose of the review: Although the majority of 1-methylcyclopropene (1-MCP) research and development has been on apple, an increasingly significant body of work is accumulating for a wide variety of fruit species. The objective of this paper is to create a snapshot of the current state-of-the-art, provide an estimate of the potential benefits for the use of 1-MCP in tree fruit crops where development is still in progress, and evaluate factors that can influence successful application. Importantly, this review summarises the perspectives of an international panel of recognised experts on the potential benefits of 1-MCP on a crop-by-crop basis. Main findings: The use of 1-MCP for improving the storability and quality of horticultural products is truly global. Currently, 27 countries use 1-MCP as the formulation SmartFresh™ on 25 different commodities, 18 of which are tree fruits. The survey indicates that postharvest experts anticipate "good, very good or excellent potential benefit" for 15 of the current 18 registrations, with apple and persimmon ranking highest. Little or no potential for benefit is envisioned for most of the fruit crops for which no registrations currently exist. Achieving consistent results, especially among those commodities not as well suited to 1-MCP use as apple fruit, will be a function of cultivar choice, preharvest factors, fruit maturity, treatment conditions, pathology, and interaction of 1-MCP and the postharvest environment. The findings illustrate that many aspects of the influence of 1-MCP on various commodities remain to be clarified before 1-MCP is fully adopted on a commercial scale. Directions for future research: There is no doubt that the commercial impact of 1-MCP will increase as further research is carried out. Nevertheless, ample investigation is needed to determine the influence of preharvest factors and harvest conditions on fruit response to 1-MCP, as well as its influence in any disease-control program. 1-MCP sprayable formulations applied during the growing season have potential as an orchard management tool to ameliorate preharvest problems (eg, abscission) in addition to improving postharvest fruit quality. Testing the effectiveness of 1-MCP on new crops as a complement to low temperature storage and modified atmospheres must be carried out to evaluate the feasibility and limitations of these technologies on a commercial scale. The influence of 1-MCP on consumer acceptance does not seem to be a problem for apples, but could represent a stumbling block for other tree fruit crops and merits further research.
Different dormancy-breaking pretreatments were assessed in order to improve germination of caper ... more Different dormancy-breaking pretreatments were assessed in order to improve germination of caper ( Cuppuris spinosa L. ) seeds. High germination percentages were obtained using concentrated sulfuric acid, followed by either a 90&n soaking procedure in a 100 ppm gibberellin (GA,,+7) solution, or adding 0.2% potassium nitrate to the test substrate. Results obtained by means of a surgical treatment clearly suggest that the dormancy of the caper seed is imposed by its covering structures. * Corresponding author. 0304-4238/95/$09.50 0 1995 Elsevier Science B.V. All rights reserved SSDIO304-4238(95)00779-2
Sweet cherry (Prunus avium L.) is a fruit of increasing economic importance though it is less sig... more Sweet cherry (Prunus avium L.) is a fruit of increasing economic importance though it is less significant than other stone fruit species such as peach. Cherry has received little attention concerning nitrogen (N) uptake and dynamics in mature trees. The aim of this work was to determine N uptake and partitioning as influenced by the timing of fertilizer application in 7-year-old sweet cherry trees cultivated in a cold region (Los Antiguos, Santa Cruz, Argentina; 71 • 38 W, 46 • 32 S). Nitrogen (95 kg ha −1 ) was applied as ammonium nitrate to a soil with 'Bing' sweet cherry trees grafted onto Prunus mahaleb rootstocks. Fertilization was split into two equal applications per treatment, involving either the commercial fertilizer ammonium nitrate or the same fertilizer labelled with 15 N isotope (10% atom.). Treatments consisted of one early spring (full bloom, October 2005) or one summer (late January 2006, 15 days after harvest) application of 15 N ammonium nitrate to three replicate trees. Fruit were harvested in early January and leaves were collected at both full canopy and leaf fall. All trees were excavated in winter (August, 2006). Trees were partitioned into their components: trunk, branches (current-season shoots, 1-year-old and over-1-year-old branches), buds of the same age, small roots (less than 1 mm thick), large roots, leaves (sampled in February and April), and fruit (collected at harvest). Those components were dried and analysed for total N and 15 N content. Total N per tree and N content derived from the fertilizer did not differ between treatments. Summer postharvest 15 N application partitioned not only to structural components (trunk and roots) but also to buds and leaves. Uptake efficiency was significantly (p = 0.0113) higher in the spring than in the summer application (65.7% vs. 37.44%). Nevertheless, 52.5% of N applied in spring was lost due to harvest and summer pruning. This emphasizes the importance of the postharvest N fertilization which increases N accumulation in both reserve organs and buds though, according to our data, it is less efficiently used. The extent of nitrogen uptake, efficiency of use and partitioning in the following growing seasons are still open questions that deserve further research.
Wooden bin-stored 'Bartlett' pears (Pyrus communis L.) were hydrocooled (HC) or forced-air cooled... more Wooden bin-stored 'Bartlett' pears (Pyrus communis L.) were hydrocooled (HC) or forced-air cooled (FAC) and immediately treated or not with 1-methylcyclopropene (1-MCP) for 24 h. 1-MCP gas concentrations used were 0, 0.3 or 0.6 L L −1 (called 0, 0.3 and 0.6, respectively). Fruit were subsequently kept at 20 • C for 20 d or stored at −0.5 • C and 95% RH for 60, 90, 120 or 150 d. After cold storage, fruit were kept at 20 • C for up to 16 d for further ripening. In another experiment, pears stored in wooden bins (W) or plastic bins (P) were all hydrocooled, treated or not with 0.5 L L −1 1-MCP (called 0.5 and 0, respectively), stored at −0.5 • C and 95% RH for 0, 30, 60, 90 or 120 d, and transferred to 20 • C for further ripening. In FAC pears, increasing 1-MCP concentrations usually resulted in delayed increases in ethylene production and lower ethylene production rates, as well as delayed softening. In contrast, HC-0.3 pear firmness did not differ from that of HC-0 fruit after cold storage. Generally, HC-0.3 pears displayed higher ethylene production and lower firmness values than FAC-0.3 pears after a 7-d exposure to 20 • C, regardless the length of cold storage. FAC-0.6 pears always showed lower ethylene production rates and higher flesh firmness values than HC-0.6 fruit. Soluble solids concentration was not consistently affected by 1-MCP. FAC-0.3 and HC-0.6 fruit showed higher titratable acidity values than HC-0 fruit after 0, 60, 120 and 150 d of cold storage plus 7 d at 20 • C. Effectiveness of 1-MCP treatments on HC pears was influenced by the bin material; P-0.5 pears were firmer than W-0.5 pears after 7 d at 20 • C, regardless the length of the cold storage. HC-0.5 fruit exposed to −0.5 • C for 90 d reached eating quality (firmness ≤23 N) by day 7 if placed in W, and by day 21 when stored in P. Results and previous evidence suggest that wet wooden bin material may represent a major though unpredictable source of 1-MCP sorption that could bind a significant percentage of the 1-MCP applied. When used at relatively low doses 1-MCP partial removal by wet wooden bins can compromise the application effectiveness for controlling ethylene action.
The terms 'soft fruit' have been used to refer to different commodities including strawberries, b... more The terms 'soft fruit' have been used to refer to different commodities including strawberries, blueberries and several species of the genus Rubus. Most work in 'soft fruit' ripening regulation has been done on strawberry. Auxin has been shown to be a repressor of several ripening-associated genes which led to hypothesize that reduction in auxin levels in the receptacle could activate those genes. Despite that, some evidence suggest that that is only part of the story and that other factors are also involved in the regulation of 'soft fruits' ripening process. Softening is one of the most dramatic changes observed in 'soft fruit' ripening. Early reports on strawberry stated that the average molecular size of hemicelluloses greatly declines during ripening. In contrast, later work showed that pectin size is reduced while only slight depolymerization occurs in hemicellulosic polymers. Pectin metabolism has recently shown to be a major modification accompanying softening in species of the genus Rubus. Contrarywise, a reduction in glucan content and downshifts in hemicellulose molecular size are the main changes observed in blueberry. Extension of 'soft fruit' postharvest life has been an ongoing challenge. Strategies to reduce 'soft fruit' losses include selection of firmer genotypes and optimum postharvest handling procedures. A single postharvest technique is unlikely to fully control postharvest losses but new tools such as UV radiation, heat treatments or chitosan coatings may be added to the overall management plan (cooling conditions, modified atmospheres) to further delay softening and prevent decay losses. Biotechnology may be useful to address some of the concerns about bramble quality attributes (e.g. increased fruit firmness, improved flavor) and engineered resistance may be a sustainable method to control Botrytis cinerea.
52 Introduction The Prunoideae, a subfamily of Rosaceae, includes several species producing edibl... more 52 Introduction The Prunoideae, a subfamily of Rosaceae, includes several species producing edible drupes with economic importance. In 2001, worldwide annual production of Prunoideae exceeded 28.3 million metric tons, including almost 13.5 million tons of nectarines and peaches (Prunus persica (L.) Batsch), 9 million tons of plums (Prunus domestica L.), 2.7 million tons of apricots (Prunus armeniaca L.), 1.8 million tons of sour and sweet cherries (Prunus cerasus L. and Prunus avium L. respectively) and 1.3 million tons of almonds (Prunus amygdalus Batsch = Prunus dulcis (Miller) D.A. Webb) (Table 1) 1 . Prunus species are characterized by developing only one ovary in which two ovules typically form; one of them degenerates soon after anthesis. The fruit is a drupe where the mature stony endocarp together with the seed forms a propagation unit comparable to a botanical seed surrounded by its protective testa.Breeding practices in Prunus must address the challenges resulting from the...
Abstract A full-length cDNA clone named PsARF/XYL was obtained from Prunus salicina Lindl., and d... more Abstract A full-length cDNA clone named PsARF/XYL was obtained from Prunus salicina Lindl., and determined to encode a putative α-l-arabinofuranosidase/β-d-xylosidase belonging to glycoside hydrolase (GH, EC 3.2.1.-) family 3. Two related PsARF/XYL cDNAs were amplified, one from a fully-spliced transcript (PsARF/XYLa) and another one from an intron-retained transcript (PsARF/XYLb). The protein deduced from PsARF/XYLb is a truncated peptide at C-terminus that conserves the active-site amino acid sequence. High levels of PsARF/XYLa and PsARF/XYLb transcripts are detectable in several plant tissues. PsARF/XYLb transcripts accumulate progressively during the phase of exponential fruit growth but they become barely noticeable during on-tree ripening, or after a 6-h exposure of preclimacteric full-size plums to ethylene. In contrast, PsARF/XYLa is expressed throughout fruit development, and transcript accumulation parallels the climacteric rise in ethylene production during ripening. PsAR...
Preclimacteric European pears (Pyrus communis L. cv. "Bartlett") were untreated or treated with 0... more Preclimacteric European pears (Pyrus communis L. cv. "Bartlett") were untreated or treated with 0.4 l l −1 1-methylcyclopropene (1-MCP) for 10 h at 20 • C and then kept at 20 • C, or stored at 1 • C for 30 or 60 days before transfer to 20 • C. Other lots were treated with 0.4, 0.8, 1.2, or 1.6 l l −1 1-MCP after 30 or 60 days of storage at 1 • C. 1-MCP-treated pears kept at 20 • C had lower ethylene production and slower softening than untreated fruit. Treated fruit were more than 75 N firmer than control fruit after a 6 day storage period. Fruit color changes were also delayed by 1-MCP treatment. However, additional color sorting may be necessary to reduce variability in response of fruit to 1-MCP in commercial situations. 1-MCP-treated fruit had lower total glycosidase (␣and -d-galactosidase, ␣-l-arabinofuranosidase, -d-xylosidase, and -d-glucosidase) activities. When 1-MCP was applied to fruit prior to cold storage (CS) at 1 • C, the synergistic interaction of cold and 1-MCP resulted in an extended postharvest life after transfer to room temperature, with concomitant delayed ethylene and respiratory level increases, retarded color development and retention of firmness. In contrast, application of 0.4-1.6 l l −1 1-MCP after 30 or 60 days of cold storage did not affect most ripening indices. These findings point to the experimental and commercial utility of 1-MCP in "Bartlett" pear postharvest management.
Tomato fruit show physiological disorders when exposed to temperatures at or above 30°C. It has b... more Tomato fruit show physiological disorders when exposed to temperatures at or above 30°C. It has been suggested that the cz-and p-galactosidases ((Y-and /I-Gal), as well as the endop-mannanase could play roles during fruit ripening. Their pattern of activities was followed in detached tomato fruit, and the degree of inhibition of the activity at high temperatures was evaluated. The potential resumption of the enzyme activity when fruits were transferred to a room-temperature environment was also studied. Mature-green fruits were incubated at: (a) 36°C for 2 days, (b) 40°C for 2 days, or (c) 40°C for 2 days +36"C for another 2 days. After heat treatments, fruits were transferred to a 21°C dark environment. Control fruit were stored at 21°C. In the control fruit, activity was higher for a-Gal than for &Gal and revealed slightly increasing patterns toward the red-ripe stage. Endo-jl-mannanase activity was not detected in mature-green tomatoes but appeared at the breaker stage and rose rapidly, reaching constant values at the red-ripe stage. The firmness and enzymatic activities of fruits initially treated at 36°C for 2 days were similar to those of the control group. Galactosidase activity decreased in tomatoes incubated at 40°C for 2 days; and in those whose heat treatment was extended another 2 days at 36°C the aand &Gal reached a minimum of l/S and l/25, respectively, of the initial activity on the fourth day. The activity of the endo-fi-mannanase could be detected only 6 days after the fruit had been transferred to a 21°C environment and increased slowly up to 24% of that attained by the control group. a-Gal showed a low rate of recovery but B-Gal activity recovered after 16 days at 21°C. Results could be associated with an active role of these enzymes on the fruit softening process. * Corresponding author. Fax: +54 (I) 522-8395. 0925-.5214/%/$15.00 Copyright 0 1996 Elsevier Science B.V. All rights reserved HI SO925-5214(96)00014-2 G.O. So-i et al. / Posthamest Biology and Technology 9 (I 996) 49-63
Transient (1 h) treatment of breaker tomatoes (Lycopersicon esculentum Mill. cv. Bonanza) with ex... more Transient (1 h) treatment of breaker tomatoes (Lycopersicon esculentum Mill. cv. Bonanza) with exogenous GA 3 or IAA at a high concentration (20 mM) resulted in a two-to four-fold increase compared with the control in ethylene biosynthesis during a 9-day experiment. This sharp increase in ethylene emission is characteristic of a stress response. Both phytohormones promoted the activity of 1-aminocyclopropane-1-carboxylate synthase that probably accounts for most of the enhanced ethylene synthesis. GA 3 and IAA also stimulated total ␣and -galactosidase and ␣-L-arabinofuranosidase activity but showed some potential to delay ripening parameters, among them, fruit softening, chlorophyll loss, and total carotenoid synthesis. GA 3 -or IAA-treated fruit did not respond to exogenous 100 ppm C 2 H 4 with an increase of autocatalytic ethylene production. Moreover, GA 3 or IAA applied alone showed a faster increase in ethylene biosynthesis than that achieved by exogenous C 2 H 4 . The combination of GA 3 and C 2 H 4 -supplemented atmosphere did not result in synergistic effects on glycosidase activity except for a few cases. IAA-treated fruit exposed to C 2 H 4 -supplemented atmosphere did not promote additional glycosidase activity but rather seemed to have antagonistic effects on -galactosidase during the first few days of the experiment. Glycosidase response to GA 3 and IAA treatments did not correlate with changes in tomato pericarp firmness, thus suggesting that some isoforms may have no role in tomato fruit softening.
Antioxidante en berries y otros frutos y factores que afectan su acumulación. Antioxidants in berries and another fruits, and factors that affect their accumulation
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