Fruit Quality Indices Research Articles

Changes in the sugar-acid ratio in apple fruits depending on the applied storage technology

Physiological-biochemical changes that occur during the post-harvest period lead to the deterioration of the quality of agricultural products. The main biochemical indices of fruit quality, which determine their taste and consistency, are sugars and organic acids. As the apples ripen, the total amount of sugars increases and the acidity decreases. The taste of the fruits is determined not only by the absolute content of organic acids and sugars, but mainly by their ratio in the fruit. The fruits treated post-harvest with the Fitomag preparation were characterized at the time of release from storage by a more harmonious taste, compared to the control fruits. The sugar-acid ratio can be used as a diagnostic indicator of quality, by monitoring the biochemical content of fruits in storage.

Effects of green manure planting mode on the quality of Korla fragrant pears (Pyrus sinkiangensis Yu).

In this study, a three-year experiment on the fragrant pear orchard was conducted to investigate the effects of different varieties of green manure on the Korla fragrant pear fruit quality, with a view to finding a suitable green manure planting mode for Korla fragrant pear orchard. Green manures were planted in spaces among rows of pear trees, and then smashed and pressed into the soil as fertilisers by the agricultural machinery equipment in their full bloom period. In the experiment, four planting modes of green manure had been set for comparison: SA: Leguminosae green manures alfalfa (Medicago sativa L.), SP: Poaceae green manures oats (Avena sativa L.), ST: Cruciferae green manures oilseed rape (Brassica napus L.), and S: orchard authigenic green manures (Chenopodium album L., Mulgedium tataricum (L) DC., and Phragmites australis (Cav.) Trin. ex Steud.). Apart from that, eleven fruit quality indicators were analyzed to evaluating the effects of different green manure planting mode on the quality of fragrant pear. According to analysis of variance (ANOVA) results, there were significant differences among four planting modes in terms of nine fruit quality indicators (P<0.05). In addition, the correlation analysis (CA) results revealed that there were different degrees of correlations among quality indicators. On this basis, repeated information among indicators was eliminated by principal component analysis (PCA), thus simplifying and recombining the three principal components. All in all, these three principal components reflect appearance traits, internal nutritive value and taste of fruits, respectively. Specifically, SA significantly improved the internal quality and nutritive value of fruits, SP improved the physical traits of fruits, and ST significantly improved the taste of fruits. Based on the PCA results, a comprehensive evaluation model of fruit quality was constructed. The are comprehensive fruit quality scores:SA>SP>ST>S.

The Alteration of Tomato Chloroplast Vesiculation Positively Affects Whole-Plant Source-Sink Relations and Fruit Metabolism under Stress Conditions.

Changes in climate conditions can negatively affect the productivity of crop plants. They can induce chloroplast degradation (senescence), which leads to decreased source capacity, as well as decreased whole-plant carbon/nitrogen assimilation and allocation. The importance, contribution and mechanisms of action regulating source-tissue capacity under stress conditions in tomato (Solanum lycopersicum) are not well understood. We hypothesized that delaying chloroplast degradation by altering the activity of the tomato chloroplast vesiculation (CV) under stress would lead to more efficient use of carbon and nitrogen and to higher yields. Tomato CV is upregulated under stress conditions. Specific induction of CV in leaves at the fruit development stage resulted in stress-induced senescence and negatively affected fruit yield, without any positive effects on fruit quality. Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated protein 9 (CRISPR/CAS9) knockout CV plants, generated using a near-isogenic tomato line with enhanced sink capacity, exhibited stress tolerance at both the vegetative and the reproductive stages, leading to enhanced fruit quantity, quality and harvest index. Detailed metabolic and transcriptomic network analysis of sink tissue revealed that the l-glutamine and l-arginine biosynthesis pathways are associated with stress-response conditions and also identified putative novel genes involved in tomato fruit quality under stress. Our results are the first to demonstrate the feasibility of delayed stress-induced senescence as a stress-tolerance trait in a fleshy fruit crop, to highlight the involvement of the CV pathway in the regulation of source strength under stress and to identify genes and metabolic pathways involved in increased tomato sink capacity under stress conditions.

Changes in Fruit Quality and Sugar Components of Wild Actinidia eriantha of Different Varieties (Lines) at the Ripening Stage

In order to better understand the changes in fruit quality and soluble sugar components in wild Actinidia eriantha at the soft ripening stage, this study explored the fruit quality indexes, soluble sugar components, sucrose metabolism-related enzyme activities and the expression of sucrose metabolism-related enzyme genes in wild A. eriantha germplasm resources. The results showed that the fruit quality of wild A. eriantha at the soft ripening stage was quite different, and the coefficient of variation of fructose content was the largest, followed by sucrose and glucose. Principal component analysis and systematic clustering analysis showed that the comprehensive performance of fruit quality indexes of M28 and M10 was the most prominent. The accumulation and composition of soluble sugar components in different wild A. eriantha varieties (lines) were not consistent. The activities of sucrose metabolism enzymes among wild A. eriantha varieties (lines) were different to some extent. The sucrose metabolism-related enzyme genes among wild A. eriantha germplasm resources had different expression patterns. The results will contribute to understanding the fruit quality changes and the mechanism of sugar metabolism in wild A. eriantha at the soft ripening stage, and lay a foundation for the protection and utilization of wild A. eriantha germplasm resources.

Optimizing the postharvest supply chain of imported fresh produce with physics-based digital twins

In the postharvest chain of fresh horticultural produce, it is often challenging to quantify how much potential measures improve the supply chain. This study compares and quantifies the impact of the different measures in preserving the quality of fresh produce in the cold chain. We employed physics-based digital twins of fresh produce. This digital twin is the virtual representation of fresh produce that can calculate the temperature distribution within the fruit and link these to quality decay based on the measured air temperature data. In this study, 95 shipments were monitored in the cold chain for four fruits (cucumber, eggplant, strawberry, and raspberry) imported from Spain to Switzerland. Using these temperature data as inputs for the digital twins, their hygrothermal response and physiological evolution to evaluate different optimization strategies were simulated. We showed that shortening the time length of shipment by one day at the distribution center resulted in 18% higher fruit quality index for cucumber and eggplant and 60% higher for berries. Lowering the shipment temperature by 5 °C extended the shelf life of strawberry on average by 36% and raspberry by 73%. Lowering the shelf temperature in retail stores by 5 °C prolonged the shelf life of the four fruits, on average, by about 40%, but the reduction is very fruit-dependent. For every 10% increase in relative humidity in the surroundings of unpacked fruit from during transport and at the distribution center by adjusting hygrothermal climate control, mass loss was reduced by 20% for all the studied fruits. Finally, evaporative cooling at the retail stores, which could be done by dry misting, extended the shelf life by more than 60%, due to the induced temperature reduction. Taking advantage of this digital twin's capability to evaluate the different scenarios, we can quantify the impact of cold chain optimizations more efficiently and cost-effectively in the design phase.

The Effect of Harvest Date and Storage Conditions on the Quality of Remontant Strawberry Cultivars Grown in a Gutter System under Covers

The storage characteristics of three remontant strawberry cultivars San Andreas®, Albion® and Murano® were studied in 2018–2020. The short-term storage conditions (7 days) of strawberries used in the study significantly affected fruit quality indicators. The highest quality of stored strawberries was provided by controlled atmosphere (CA) conditions, as evidenced by the typically highest fruit firmness and the lowest natural loss of strawberry weight. The modified atmosphere packaging (MAP) conditions obtained in the Xtend® bags provided a similar good storage effect for strawberries. Strawberries stored in MAP bags had the lowest respiratory intensity, and their firmness and the percentage of rotten fruit were the same as those stored in a controlled atmosphere. In addition, MAP bags were effective in reducing the weight loss of stored strawberries. The quality of strawberries stored in a conventional air storage (AA) was slightly lower compared to the fruit stored in a controlled and modified atmosphere. This was due to their lower firmness and significantly higher respiration intensity and higher weight loss. In addition, the percentage of rotten fruit, although low, has always been the highest among AA strawberries. The quality of the strawberries also depended on the date of fruit harvest. Strawberries harvested later, compared to those collected earlier, were generally characterized by higher firmness, lower acidity and lower respiration intensity.

Physics-driven digital twins to quantify the impact of pre- and postharvest variability on the end quality evolution of orange fruit

Currently, there are differences in the quality loss between individual fruit upon arrival at retail. These differences in fruit quality stem from pre-harvest biological variability between individual fruit at harvest and postharvest variations in hygrothermal conditions between refrigerated shipments. The impact of these pre-harvest biological and postharvest variability on the final quality of each fruit that reaches the consumers remains largely uncharted. In this study, we addressed this knowledge gap by developing physics-based digital twins of orange fruit to unveil how pre-harvest and postharvest variability affect the final fruit quality upon arrival at retail. Markov chain Monte Carlo method was used to generate a realistic 'virtual' population of 1000 individual orange fruits at harvest. Afterwards, the impact of pre-harvest biological variability and variations in hygrothermal conditions between shipments on several orange quality metrics, including mass loss, fruit quality index (FQI), remaining shelf life (RSL), chilling injury severity (CI), total soluble solids (TSS), color, and Mediterranean fruit fly (MFF) mortality was quantified. Results showed that pre-harvest biological variability causes variations in mass loss of oranges at retail by up to 1.2%, FQI by up to 5% and RSL by more than 2 days. The postharvest variability between shipments causes high variations in mass loss of oranges at retail by up to 4%, FQI by more than 20%, RSL up to 3 days, and CI up to 5%. The study also revealed that compared to pre-harvest biological variability, postharvest variability between shipments could increase the variations in RSL of oranges at retail by 75%, FQI by 50%, and mass loss by ∼10%. This work helps improve our understanding of the variability in the end fruit quality upon arrival at retail.

Effects of Harvest Maturity on the Fruit Quality of Different Flesh-Type Peach Stored at Near-Freezing Point Temperature.

To investigate the peach fruit flesh types (soft-melting, hard-melting, stonyhard and non-melting) and harvest maturity level suitable for near-freezing temperature storage (NFTS), eight peach cultivars that had four flesh types were used as test materials. Changes in fruit respiration intensity and ethylene release rates, as well as the differences in quality indexes, such as soluble solids content (SSC), firmness, color difference, pigment content, soluble sugar and organic acid component content, of three fruit maturity levels (70%, 80% and 90% maturity) under NFTS conditions were analyzed and compared. The fruit quality indexes of peach having different maturity levels and flesh types changed little during NFTS. The SSC and total sugar content of hard-melting and stonyhard peach fruit were higher than those of other flesh types during NFTS. Those fruit maintained greater firmness at the end of the storage period. The differences in respiration intensity and ethylene release rate were small, but for fruit coloring, hard-melting fruit performed better than stonyhard fruit. The 80%, compared with the 90%, maturity stage maintained more fruit moisture, had less fruit mass loss and maintained a greater edible firmness. It effectively impeded the fruit senescence process and was the most suitable maturity for NFTS. Thus, the hard-melting peach maintained the highest commercial value and desirable storage characteristics under NFTS conditions, and its 80% maturity level was the most suitable for NFTS.

Zeolites and Biochar Modulate Olive Fruit and Oil Polyphenolic Profile.

Soil degradation processes and climate change threaten the sustainability of Mediterranean rainfed olive orchards, with repercussions on crop yield and quality of olives, olive oil and olive by-products. Using soil amendments can enhance soil fertility for sustained environmental quality and plant performance. For two years, we evaluated, under rainfed conditions, the effects of a fertilizer compound (FC) and its combination with zeolites (ZL) and biochar (BC) amendments on soil moisture, yield, fruit and oil polyphenols and quality indices. The polyphenolic composition was strongly influenced by treatments, although no effects were observed on crop yield. ZL improved soil moisture (average increase of 26.3% compared to FC), fruit fatty acid composition (increase of 12.4% in oleic/linoleic ratio in 2018) and oil quality, BC enhanced the concentrations of polyphenols with high nutritional value (average annual increase of 25.6, 84.8 and 11.6% for 3,4-dihydroxyphenylglycol, oleuropein and rutin, respectively). In contrast, olive oil from FC fruits showed the poorest quality, with oxidation and hydrolytic breakdown signals. The applied soil amendments appear to be a promising sustainable strategy to implement in olive rainfed orchards.

Systematic analysis of the sugar accumulation mechanism in sucrose- and hexose- accumulating cherry tomato fruits

BackgroundSugar content is an important indicator of fruit quality. Except for a few wild tomato species that accumulate sucrose in the fruits, most cultivated tomato species accumulate hexose. Although several studies have focused on wild sucrose-accumulating tomato, the sucrose accumulation mechanism is still unclear.ResultsHere, two homozygous inbred cherry tomato lines (‘TB0023’ and ‘TB0278’, which accumulated sucrose and hexose, respectively) were selected to analyze the sugar accumulation mechanism. Carbohydrate analysis, cytological observation, gene expression and enzyme activity analysis and proteomics methods were used in this study. The results indicated that glucose and fructose were absolutely dominant in the soluble sugar content of hexose-accumulating cherry tomato fruit, while sucrose and a certain proportion of hexose were the main forms of soluble sugar in sucrose-accumulating cherry tomato fruit. The phloem unloading pathway of the hexose-accumulating cherry tomato fruit switched from symplastic to apoplastic during fruit development, and the sucrose-accumulating cherry tomato probably had a mixed unloading pathway involving the symplastic and apoplastic. High activity of acid invertase (AI), sucrose phosphate synthase (SPS), sucrose synthase (SS) and sugar transporters LeSUT1, SlSWEET2a and SlSWEET12c were important factors for hexose accumulation in the hexose-accumulating cherry tomato fruit, while LeSUT2, SPS, SS, SlSWEET1b, SlSWEET5b, SlSWEET11b, SlSWEET7a, SlSWEET14 were responsible for solute sugar accumulation in the sucrose-accumulating cherry tomato.ConclusionsThis study provides detailed evidence for elucidation of the tomato sugar accumulation mechanism from the perspective of cell structure, physiology and molecular biology, providing a theoretical basis for the improvement of tomato quality and aiding the utilization of tomato genetic resources.

Dynamic Changes of Fruit Physiological Quality and Sugar Components during Fruit Growth and Development of Actinidia eriantha

‘Ganlv 1’ is a new cultivar of Actinidia eriantha selected from the wild natural population, which has the advantages of moderate taste, high yield, easy peeling and high ascorbic acid (AsA) content. In this study, ‘Ganlv 1’ was used to explore the changes in fruit quality, soluble sugar components, sucrose metabolism-related enzymes activities and sucrose metabolism-related enzyme genes’ expression during the fruit’s development. The results showed that, except for AsA, the changes in the fruit quality index and fruit growth and development during the development of ‘Ganlv 1’ basically exhibited the same trend. The fruit shape index was different in the different development stages of the fruit, and tended to be stable with fruit growth and development. The dynamic changes of the dry matter content indicated that the best time for fruit harvest was about 160 days after full bloom. The main sugar components in the fruit were fructose, glucose and sucrose, and sucrose and glucose were the main sugars in the soft-ripening stage. The trend of sucrose accumulation, the activities of the sucrose metabolism-related enzymes and the expression of the sucrose metabolism-related genes indicated that 130–145 days after full bloom (DAFB) might be the critical period of sucrose metabolism. The results are of great significance for clarifying the developmental characteristics and dynamic changes in the sugar components in A. eriantha fruits, and lay a foundation for further studying of the mechanism of sugar metabolism in A. eriantha.

The effect of biofertilizer “Bio Mix 1” on morpho-biological features of vegetable crops in greenhouse conditions

Research was carried out in the greenhouse of the Scientific Center of Vegetable-Melon and Industrial Crops in the period of 2018-2019. The effect of organic fertilizer “Bio mix 1” of Indian origin on morpho-biological features of plants, yield capacity, quality indicators of fruits and seeds of tomato, sweet pepper and cucumber has been studied. The results of the studies showed that in all studied crops “Bio mix 1” fertilizer promoted the plant growth, development and yield capacity, besides, the quality indicators of fruits and seeds were improved.

The study of portioned varieties of pumpkin and the possibility of using them in breeding

Growing in different ecological conditions, pumpkin varieties acquire new economic characteristics, which indicates agroecological differentiation of pumpkin. Under growing conditions in the Ararat Plain, we studied 8 portion varieties of pumpkin, which differed in the timing of the onset of phenophases, the timing of the receipt of products and yield indicators, and quality indicators of fruits. According to the growing season, the varieties were divided into early-ripening varieties - Syunik, Saporik and Veronez, mid-ripening - Volzhskaya gray 92, Children’s delicacy, Konfetka, Prikubanskaya and late-ripening - Gribovskaya winter. The yield data of variety samples were analyzed: the most productive were the Muscat varieties Saporik and Prikubanskaya with high taste qualities of fruits - 23.2±1.1 and 30.6±1.1 t/ha. Among the large-fruited pumpkins, varieties Detskaya delikatesnaya and Syunik stood out, which were distinguished by high palatability and yield - 25.3±1.0 and 23.0±1.4 t/ha, respectively. The varieties Saporik, Syunik, Detskaya delikatesnaya and Konfetka stood out for the high content of total carotenoids, in which this indicator was 16.05, 10.50, 15.22 and 18.25 mg/%, respectively.

Evaluating the Influence of Deficit Irrigation on Fruit Yield and Quality Indices of Tomatoes Grown in Sandy Loam and Silty Loam Soils

The most important biotic stress factor impacting tomato crop biophysical, biochemical, physiological, and morphological features is water stress. A pot experiment was undertaken in a greenhouse to study the drought responsiveness of tomato (Solanum lycopersicum) yield and quality indices in sandy loam and silty loam soils. For both sandy loam and silty loam soils, the water supply levels were 70–100% FC, 60–70% FC, 50–60% FC, and 40–50% FC of ETo (crop evapotranspiration) from the vegetative stage to the fruit ripening stage, calculated using the Hargreaves–Samani (HS) model compared to the time-domain reflectometer (TDR) values calibrated using volumetric water content (VWC). The experiment was conducted as a 2 × 4 factorial experiment, arranged in a completely randomized block design, with four treatments replicated four times. In this study, we examined how sandy loam and silty loam soils at different % FC affect the total marketable yield and quality components of tomatoes, concentrating on total soluble solids (Brix), fruit firmness, dry fruit mass, pH, titratable acid (TA), ascorbic acid (Vit. C), and carotenoid composition. Lycopene and β-Carotene were estimated using the UV spectroscopy method, with absorption spectra bands centered at 451 nm, 472 nm, 485 nm, and 502 nm. The results revealed that even though there were some limitations, TDR-based soil moisture content values had a strong positive correlation with HS-based evapotranspiration, with R2 = 0.8, indicating an improvement whereby TDR can solely be used to estimate soil water content. Tomato plants subjected to 40–50% FC (ETo) water stress in both sandy loam and silty loam soils recorded the highest total soluble solids, titratable acidity, ascorbic acid content, and β-carotene content at an absorption peak of 482 nm, and lycopene content at an absorption peak of 472 nm, with lower fruit firmness, fruit juice content, and fruit juice pH, and a reduced marketable yield. Similarly, tomato plants subjected to 60–70% FC throughout the growing season achieved good fruit firmness, percent juice content, total soluble solids, titratable acidity, ascorbic acid content, and chlorophyll content (SPAD), with minimum fruit juice pH and high marketable yield in both soil textural types. It is concluded that subjecting tomato plants to 60–70% FC (ETo) has a constructive impact on the marketable yield quality indices of tomatoes.

Effects of Biodegradable Liquid Film on the Soil and Fruit Quality of Vitis Franco-american L. Hutai-8 Berries

Biodegradable liquid mulch film (LF), which can be degraded naturally without harming the environment, is a new type of covering material that provides an environmentally friendly alternative to plastic mulch film (PF). In this study, the effects of LF and PF (ploughing (CK) used as a control) on the soil and fruit quality of Hutai-8 were evaluated through an experiment, and several soil physicochemical properties and indicators of fruit quality were measured. In-row mulching significantly increased the content of total potassium, available phosphorus, and available potassium in the topsoil (0–20 cm), the ripeness of the grape berries, and the content of phenolics in the skin. The effects were consistent between the two years. The effect of LF was more pronounced in the same year, indicating that LF is an effective alternative to PF. Therefore, LF can be used as an environmentally friendly substitute for PF to improve soil and fruit quality and incorporated into cultivation management plans. Correlation analysis revealed that the content of reducing sugars, flavonoids, total phenols, flavan-3-ols, and anthocyanins, as well as fruit ripeness, increased as the content of total potassium, available phosphorus, and available potassium in the soil increased.

Prediction and optimization of fruit quality of peach based on artificial neural network

Mineral nutrition is the material basis for growth and quality improvement of fruit trees. In this study, artificial neural networks (ANNs) and Multiple linear regression (MLR) models were used to study the influence of mineral nutrient elements in fruits on the peach fruit quality. The results showed that four established ANN models of the fruit quality with the Log-sigmoid transfer function and the Levenberg-Marquardt back-propagation training function can obtain the highest accuracy (R2 =0.9243, 0.9260, 0.9536, and 0.9644 respectively). The results of the sensitivity and redundancy analysis indicated that the nitrogen, phosphorus, potassium, magnesium, and iron content in fruits had the greatest contribution to these fruit quality indicators of the peach, which was of great significance to the fertilization of peach orchards and the improvement of peach fruit quality.

Effect of Individual and Selected Combined Treatments With Saline Solutions and Spent Engine Oil on the Processing Attributes and Functional Quality of Tomato (Solanum lycopersicon L.) Fruit: In Memory of Professor Leila Ben Jaballah Radhouane (1958-2021).

The results showed that soil electrical conductivity, (EC2: 7 dS/m) increased soluble solids, lycopene content, total phenolic content, hydrophilic and lipophilic radical scavenging activities (HRSA and LRSA) by 14.2, 149, 20, 46.4, and 19.0%, respectively, compared with control. Under 0.5% spent engine oil (SEO), flavonoid content decreased by 21.7% compared with the control. HRSA and LRSA of fruits subjected to EC2/SEO1 treatment were, respectively, 45.9 and 35.5% lower than control. The a*/b* ratio was positively and significantly (P < 0.01) correlated with β-carotene (R = 0.78), lycopene (R = 0.68), total vitamin C (R = 0.71), α-tocopherol (R = 0.83), γ-tocopherol (R = 0.66), HRSA (R = 0.93), LRSA (R = 0.80), and soluble solids (R = 0.84) suggesting that it may be a promising indicator of fruit quality in areas affected by such constraints. The research revealed that combined stresses induce responses markedly different from those of individual treatments, which strain the need to focus on how the interaction between stresses may affect the functional quality of tomato fruits.

Study on the Application of Electronic Nose Technology in the Detection for the Artificial Ripening of Crab Apples

Ripening agents can accelerate the ripening of fruits and maintain a similar appearance to naturally ripe fruits, but the fruit flavor and quality will be changed compared to naturally ripe fruits. To find an efficient detection method to distinguish whether crab apples were artificial ripened, the naturally ripe and artificially ripe fruits were detected and analyzed using the electronic nose (e-nose) technique in this study. The fruit quality indexes of samples were determined by the traditional method as a reference. Significant differences were found between naturally ripe and artificially ripe fruits based on the analysis of soluble sugar content, titratable acidity content, sugar–acid ratio, soluble protein content, and soluble solids content. In addition, principal component analysis (PCA), linear discriminant analysis (LDA), support vector machine (SVM), and random forest (RF) analyses were performed on the electrical signals generated by the electronic nose sensor, respectively. The results showed that the RF is the best recognition algorithm for distinguishing which crab apples were naturally ripe or artificially ripe; the average recognition accuracy is 98.3%. On the other hand, the prediction models between the e-nose response data and fruit quality indexes were constructed by partial least squares regression (PLSR), which showed that the feature value of e-nose response curves extracted by wavelet transform was highly correlated with the quality indexes of fruits, the determination coefficients (R2) of regression models were higher than 0.91. The results demonstrated that the detection technology with an electronic nose could be used to test whether the fruit of the crab apple was artificially ripe, which is an economical and efficient method.

Effects of water stress on quality and sugar metabolism in ‘Gala’ apple fruit

Sugar plays an important role in apple fruit development, appearance and quality as well as contributing to a plant's water stress response. Trehalose and the trehalose biosynthetic metabolic pathways are part of the sugar signaling system in plants, which are important regulator of water stress response in apple. The effect of water stress treatments applied to apple trees and the corresponding effects of ABA on developmental fruit quality were examined for indicators of fruit quality during fruit development. The results indicated that the severe water stress treatment (W2) occurring after the last stage of fruit cell division caused a decrease in the color and size of fruit. The moderate water stress (W1) occurring after the last stage of fruit cell enlargement (S2) caused an increase in the content of fructose and sorbitol while the apple fruit shape was not affected. These changes in sugar are related to the activity of sugar metabolic enzymes. While the enzymatic activity of vacuolar acid invertase (vAINV) was higher, that of sucrose-phosphate synthase (SPS) was lower in water stress treated fruit throughout the developmental period. This indicates that enhanced sucrose degradation and reduced sucrose synthesis leads to an overall reduced sucrose content during times of drought. Thus, water stress reduced sucrose content. Whereas the content of endogenous trehalose and ABA were the highest in water stress treated fruit. A moderate water stress (W1) imposed on apple trees via water restriction (60%–65% of field capacity) after the fruit cell enlargement phase of fruit development yielded sweeter fruit of higher economic value.

Modulation of Phytochemicals and Essential Trace Elements in Fruits of Different Tomato Cultivars by the Endophytic Fungus Penicillium pinophilum EU0013.

The present study investigated the effects of the endophytic fungus, Penicillium pinophilum EU0013 on fruit phytochemical indices and essential trace elements in five tomato cultivars. In a completely randomized design, inoculated and uninoculated seedlings of tomato cultivars (Momotaro, Rodeo, Anaya, Reika, and Cherry) were raised for sixteen weeks in a greenhouse. Fruit fresh weights and root colonization by P. pinophilum were significantly higher in the Rodeo cultivar than in the other cultivars tested. Significant effects of the cultivar, inoculation, and interaction on fruit dry weights were‍ ‍observed with higher values in Anaya inoculated with P. pinophilum. Cultivar and inoculation effects were significant for ascorbic acid and soluble sugars in four cultivars, with increases being observed due to the P. pinophilum inoculation. Lycopene levels increased in Rodeo and decreased in Anaya, while β-carotene levels increased in four cultivars due to the inoculation. Manganese concentrations were significantly increased in Cherry, while iron concentrations were increased in Reika and Cherry. Increases due to the inoculation were observed for gibberellic acids (GA1 and GA4) in Reika and Anaya, whereas decreases were detected in Cherry and Rodeo. Similar results were obtained for abscisic acids (ABA) with increases in Reika and Anaya due to the inoculation. P. pinophilum EU0013 demonstrated the ability to improve the nutritive value of tomato fruits via modulations to phytochemicals in addition to increases in Mn and Fe concentrations, particularly in Cherry and Rodeo. Cultivar responses to the P. pinophilum inoculation are a factor that need to be considered for its use in increasing fruit quality indices in tomato.