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Tomato, like most species from tropical and subtropical regions, exhibits postharvest chilling injury (PCI) when stored at low temperatures. Because of its economic importance and the functional genomics tools available, we used tomato to investigate aspects of fruit PCI development. We asked two questions: First, are there spatial-temporal differences in the development of PCI that can be detected by magnetic resonance imaging (MRI)? Here, the aim was to use a non-invasive method to study PCI progression in vivo. At mature green and breaker, the pericarp, locular tissue and columella produced distinct D-values while in contrast, there was no such differentiation in riper fruit. Although the pericarp is where most PCI symptoms are visible, this tissue showed less dynamism upon cold exposure, compared to the inner tissues as detected by MRI. This suggests the occurrence of distinct, independently modulated mechanisms contributing to the development of PCI-symptomatology. Collectively our data showed that the MRI could detect fruit ripening, its attenuation by cold, and fruit tissue-specific responses to chilling stress. The second question we asked was if epigenetic modification of the tomato genome or transcriptome influences PCI response. We examined PCI severity in fruit injected with a demethylating agent, 5- azacytidine (AZA). Two tomato genotypes exposed to varying severities of cold-stress were studied. Results suggested that AZA was able to moderate PCI in 'Micro-Tom' after 3 weeks at 2.5°C, while different patterns were observed in 'Sun Cherry' across various cold treatments. The effects of AZA on PCI were complex, multilayered and highly context-dependent.

This paper describes an approach to estimate the photosynthetic capacity and derive the optimum fruit number for each individual tree, in order to achieve a defined fruit size, which is named as the fruit bearing capacity of the tree. The estimation of fruit bearing capacity was carried out considering the total leaf area per tree as measured with a 2-D LiDAR laser scanner, LALiDAR, and key carbon-related variables of the trees including leaf gas exchange, fruit growth and respiration, in two commercial apple orchards. The range between minLALiDAR and maxLALiDAR was found to be 2.4 m² on Pinova and 4.3 m² on RoHo 3615 at fully developed canopy. The daily C requirement of the growing fruit and the associated leaf area demand, necessary to meet the average daily fruit C requirements showed seasonal variation, with maximum values in the middle of the growing period. The estimated fruit bearing capacity ranged from 33-95 fruit tree-1 and 45-121 fruit tree-1 on the trees of Pinova and RoHo 3615, respectively. This finding demonstrates sub-optimal crop load at harvest time in both orchards, above or below the fruit bearing capacity for individual trees. In conclusion, the LiDAR measurements of the leaf area combined with a carbon balance model allows for the estimation of fruit bearing capacity for individual trees for precise crop load management. [ABSTRACT FROM AUTHOR]

In cherry production, the assimilate supply to the fruit is a crucial factor for growth and formation of quality parameters. The assimilate supply per fruit is limited by the relative growth capacity of trees, represented by the leaf area to fruit ratio (LA:F). In the present study, the required leaf area per fruit (LAdemand [cm2 fruit-1]) of two sweet cherry cultivars, 'Bellise' and 'Regina', was estimated in 2018 and 2019, based on measured and interpolated values of fruit growth and fruit respiration rates. LAdemand changed daily with an overall increase during fruit development, showing average values in stage III in 2018 and 2019 of 139 cm2 and 175 cm2 in 'Bellise', while 199 cm2 and 212 cm2 were found in 'Regina', respectively. Estimated LAdemand for both cultivars was compared with measurements in cherries grown on girdled branches. In both years, estimated values exceeded measured values. In both years, positive correlation between LA:F and fresh mass, soluble solids content, and coloration was observed. The data obtained can be applied to evaluate the tree’s crop load for precise management. [ABSTRACT FROM AUTHOR]

This study presents a mathematical model to describe respiration (O2 consumption and CO2 production) and transpiration rates of minimally processed pineapple (cut into slices) as a function of temperature, relative humidity (RH) and geometric configuration. To experimentally adjust suitable models for respiration and transpiration, minimally processed pineapple (Ananas comosus) was stored in slices of three types of configuration (a complete slice with 1 centimeter of thickness, a complete slice with 2 centimeter of thickness and a half slice with 1 centimeter of thickness) at different temperature and RH. To estimate respiration rates, two possible models were compared and the most suitable one was chosen: the O2 consumption and CO2 production were modeled by using a Michaelis-Menten enzyme kinetics and by using a first-order kinetics choosing the former. Throughout the different experiments, the respiration rates were higher by increasing the storage temperature. The transpiration data shows the weight loss is linear for all the samples during the entire storage time. Transpiration was represented by considering the mass transfer (of moisture) due the water activity gradient between the produce and the atmosphere surrounding it, and the water evaporated as a consequence of absorbing the respiratory heat generated in the cut fruits. Results shows a high goodness of fit between experimental data and estimated values with the respiration-transpiration models (R² adj > 0.88). [ABSTRACT FROM AUTHOR]

Custard apple, a tropical fruit, is underutilized because of its poor storability. Researchers have worked on various aspects for improving the storage life of fruits; still its storage life is limited to few days. So to counteract this, an experiment was conducted to study the effect of modified atmosphere packaging using three different kinds of films along with low temperature storage at 8, 12 and 15 °C and observations were recorded at weekly interval. The study indicated an increasing trend in the respiration rate and ethylene production rate as well, and the rate increased with increase in storage temperature and duration. The physiological loss in weight in packed fruits showed a drastic reduction. Titratable acidity increased as storage duration while ascorbic acid shown exact reverse trend. There was significant increase in reducing sugar and total sugar as duration increased but rate was low in 8° C fruits. [ABSTRACT FROM AUTHOR]

Banana is one of the most consumed tropical fruits around the world. It is marketed nearly all year-around and has a relatively short shelf life. Fruits are harvested mature green and treated with ethylene to stimulate ripening before distribution and sale. The fruits generally ripen within 4-5 days after ethylene treatment and sold primarily at yellow stage of ripening. After turning yellow the fruit becomes unsuitable for marketing in 1-3 days. Thus 1-2 days of improvement in the fruit shelf life could enhance the market value of banana. Previous studies conducted in our laboratory have demonstrated that both pre- and postharvest application of lysophosphatidylethanolamine (LPE) can retard aging and improve shelf life of various fruits. The objective of this study was to investigate the possibility of improving shelf life of banana fruit by a postharvest dip in LPE. For this purpose, whole fruits obtained from the market at ripeness stage of 2.5 (about 75% green) were dipped in solution of 500 ppm LPE for 30 minutes and observed for a period of five days at room temperature. Each treatment was applied to 50 uniform fruits. From each hand bought, an equal number of fruits were separated for LPE and control treatments to reduce the variability. Five days after dip treatment, the fruit treated with LPE were firmer and thicker as compared with the control. Starch breakdown was also delayed in the LPE-treated fruits. LPE treatment slowed the development of brown spots on the peel tissue. Both peel and pulp tissue of LPE-treated fruits had lower ion leakage compared with the control. Fruit peel slices treated with LPE for 3 hours also showed a decrease in ion leakage and respiration rate at 24 hours after treatment. Results of the present study indicate that a postharvest dip treatment with LPE may improve shelf life of banana fruit by 1-2 days. These results suggest that LPE may improve shelf life by maintaining membrane integrity, reducing respiration, and slowing the breakdown of starch and cell walls during ripening and senescence of banana fruit tissue. [ABSTRACT FROM AUTHOR]

MAP is a dynamic system where respiration of the packaged product and gas permeation through the packaging film takes place simultaneously. The desired level of O and CO in a package is achieved by matching film permeation rates for O and CO with respiration rate of the packaged product. A mathematical model for MAP of fresh fruits applying enzyme kinetics based respiration equation coupled with the Arrhenious type model was developed. The model was solved numerically using MATLAB programme. The model was used to determine the time to reach to the equilibrium concentration inside the MA package and the level of O and CO concentration at equilibrium state. The developed model for prediction of equilibrium O and CO concentration was validated using experimental data for MA packaging of apple, guava and litchi. [ABSTRACT FROM AUTHOR]

The changes in abscissic acid (ABA) and jasmonic acid (JA) contents during fruit development of dragon fruit (Hylocereus undaatus) were determined. Associated changes in respiration, 1-aminocyclopropane-1-carboxylic acid (ACC) contents, and sugar levels were also measured. ACC content and respiration rate were high at early fruit development stages and gradually decreased as the fruit matured and ripened. In the pulp, ABA content increased before the increase in glucose and fructose contents. JA contents in the peel and pulp were high at the immature stage and decreased toward maturation. The results indicate that dragon fruit is non-climacteric and that JA may have a role in cell division in the developing fruit while ABA may induce fruit maturation. [ABSTRACT FROM AUTHOR]

Jujube yield and fruit characteristics can be clearly modified by water deficit imposed during fruit maturation. One essential (cystine (Cys-cys)) and seven non-essential (4-hydroxyproline (p-Hyp), α- aminoadipic acid (AADA), ornithine (Orn), β-aminoisobutyric acid (BAIB), α-amino-n-butyric acid (AABA), cystathionine (Cysta), and homocystine (Hcys-cys)) amino acids were identified for the first time. Fruits from plants exposed to moderate water deficit during the maturation stage (T1) initiated the ripening phase earlier than control (T0) fruits and had an improved eating quality. Fruits subjected to severe water deficit (T2) showed changes in their physical characteristics and reached a more advanced degree of ripening than T0 and T1 fruits, with not only most of the fruit chemical characteristics that determine taste being improved but also the nutritional value. The decrease in the asparagine (Asn) content of the fruit as a result of severe water deficit is a positive aspect, which prevents acrylamide formation during heat-processing of the fruit. [ABSTRACT FROM AUTHOR]

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The respiratory behavior of fresh-cut melon under modified atmosphere packaging at various temperatures was characterized to assess the potential for shelf life extension through low-oxygen and to generate information for the development of appropriate packaging conditions. Cantaloupe melon (Cucumis melo var. cantalupensis 'Olympic Gold') cubes were packaged and stored at 0, 5, 10, and 15 °C. Packages attained gas equilibrium after 5 days at 10 °C, 6 days at 5 °C, and 10 days at 0 °C. In cubes stored at 15 °C, decay started before steady-state gas levels were reached. Respiration rates were measured and respiratory quotient calculated once steady-state O2 and CO2 partial pressures were achieved inside the packages. O2 uptake increased with temperature and O2 partial pressure (pO2 pkg), according to a Michaelis-Menten kinetics described by Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed. Respiratory parameters were modeled as an exponential function of temperature: Ro2 {[1.34 x 10-17 x e(0.131 x T) x pO2 pkg]/[1.15 x 10-24 x e (0.193 x T) x pO2 pkg]} (R² = 0.95), Q10 = 3.7, and Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed. A good fit to the experimental data was also obtained considering Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed. as constant: Ro2 = {[4.36 x 10-14 x e(0.102 x T) x pO2 pkg]/[0.358 + pO2 pkg]} (R² = 0.93), Q10 = 2.8, and Due to image rights restrictions, multiple line equation(s) cannot be graphically displayed. These results provide fundamental information to predict package permeability and steady-state pO2 pkg required to prevent anaerobic conditions and maximize shelf life of fresh-cut cantaloupe. The kinetics of respiration as a function of pO2 suggests that no significant reductions in respiration rate of fresh-cut cantaloupe can be achieved by lowering O2 levels. [ABSTRACT FROM AUTHOR]

This study, as a preliminary step toward the definition of a carbon budget model for pistachio trees (Pistacia vera L.), aimed at estimating and evaluating the dynamics of respiration of vegetative and reproductive organs of pistachio tree. Trials were performed in 2005 in a commercial orchard located in Sicily (370 m a.s.l.) on five bearing 20-year-old pistachio trees of cv. Bianca grafted onto Pistachio terebinthus L. Growth analyses and respiration measurements were done on vegetative (leaf) and reproductive (infructescence) organs during the entire growing season (April–September) at biweekly intervals. Results suggested that the respiration rates of pistachio reproductive and vegetative organs were related to their developmental stage. Both for leaf and for infructescence, the highest values were observed during the earlier stages of growth corresponding to the phases of most intense organ growth. The sensitivity of respiration activity to temperature changes, measured by Q10, showed an increase throughout the transition from immature to mature leaves, as well as during fruit development. The data collected were also used to estimate the seasonal carbon loss by respiration activity for a single leaf and a single infructescence. The amount of carbon lost by respiration was affected by short-term temperature patterns, organ developmental stage and tissue function. [ABSTRACT FROM PUBLISHER]

We estimated translocatory balance in fruit of the tropical tree Durio zibethinus Murray on the basis of a compartment model. Rates of fruit respiration, dry weight growth and translocation increased with time. Over the 8.2 weeks of fruit development, the relative distribution of translocation was 80% to dry weight growth and 20% to respiration. The ratio of respiration rate to translocation rate, which ranged from 14 to 32%, tended to decrease with time, whereas the ratio of dry weight growth rate to translocation rate, which ranged from 68 to 86%, tended to increase with time. The relationship between dry weight growth rate and translocation rate was fitted by a power function, where dry weight growth rate was statistically proportional to translocation rate. The relationship between respiration rate and translocation rate was formulated by a smooth curve, where respiration rate increased as translocation rate increased. Examination of these ratios with respect to the translocation rate indicated that the dry weight growth rate/translocation rate ratio increased slightly with increasing translocation rate, whereas the respiration rate/translocation rate ratio decreased with increasing translocation rate. A comparative analysis of these results with those obtained for Cinnamomum camphora (L.) J. Presl revealed a lower ratio of translocation to dry weight growth in D. zibethinus than in C. camphora, indicating that D. zibethinus fruits have a low translocatory efficiency. [ABSTRACT FROM AUTHOR]