To investigate the effects of night temperature on sugar accumulation in watermelon fruit, fruits were treated with higher nighttime temperature under a greenhouse. The minimum nighttime ambient temperature of the heating box (18 °C) was approximately equal to 6 °C higher than that of the control. The heat-treated fruit weighed at the end of heating treatment, 16 days after anthesis (DAA), was greater than that of control, but fruit weight at harvesting, 42 DAA, was almost the same in both treatments. Cells of all portions of the heat-treated fruit at 16 DAA were much larger than those of the control, and cells in the outermost rectangular parallelepipeds (RPs; 15-mm long samples that were serially collected from a 10-mm thick disk along a 10-mm wide strip removed at the maximum transverse diameter of the fruit) of the heat-treated fruit were 80 micrometer or more larger than those of the control. At 16 DAA, the number of RPs with sucrose contents of 2 g·L-1 or more were six and nine in control and heat-treated fruit, respectively. At 42 DAA, content in the outer RPs of the heat-treated fruit was greater than that in the outer RPs of the control. The number of RPs with sucrose contents of 40 g·L-1 or more was five in the control and 11 in heat-treated fruit. Mean sucrose, glucose, and fructose in fruit at 16 DAA did not differ in the treated fruit from the control. However, the sucrose content of heat-treated fruit was 32% higher than that of the control at 42 DAA. Glucose and fructose content were lower in heat-treated fruit than in the control.

The effect of water stress on sugar and organic acid content in different portions of 'Shiranuhi' mandarin fruit ([C. unshiu × C. sinensis] × C. reticulata) was investigated. Soluble solids (SS) was higher in water-stressed fruit than in control fruit in all fruit parts. The gradient of SS in the radial direction in both control and water-stressed fruit was consistently the greatest at the outer portion and the lowest at the central portion. Water stress caused a 9 to 34% increase in sucrose content in all fruit parts compared with control fruit. The radial difference in acidity was the greatest between the mid section and the stylar end, and acidity in the axial direction was higher in the outer than in the central and the middle portions from 216 days after anthesis in water-stressed fruit. Water stress caused a 31 to 84% increase in citric acid and a 0 to 35% decrease in malic acid content in all parts compared with control fruit. Overall, water stress had a negative effect on fruit quality due to increased acidity.

Two plant growth regulators (GA3 and 2, 4-D) were exogenously applied in different concentrations alone and their combinations on Blood Red sweet orange trees during full bloom. The experiment was performed at the Experimental Fruit Garden Sq # 9, Institute of Horticultural Sciences, University of Agriculture, Faisalabad; laid out according to RCBD with 13 treatments including control replicated thrice. A single tree was taken as treatment unit. Vegetative and reproductive behaviours of the treated trees were studied to evaluate the effect of exogenous application of plant growth regulators on leaf age, vegetative growth and final fruit set. The leaf drop was significantly reduced by all treatments compared with control. The mixture treatments at all concentrations retained maximum spring leaves ranging between 38.5% (20 mg L-1) - 58.38% (45 mg L-1). The control trees had negligible number of spring leaves (3.09%). Number of leaves per flush, flush length, number of male flowers and flower drop intensity had also significant differences among treatments but no linear trend could be determined. Bud drop, hermaphrodite flowers, fruit on old shoots and fruit on current shoots were not significantly affected by the treatments. The final fruit set was significantly affected by all GA3 treatments individually as well as in mixture with maximum fruit set of 32.32% in 45 mg L-1 GA3 treated trees compared with control. Fruit yield, in terms of number of fruit per tree as well as kg per tree was significantly affected by the treatments compared with control. There was positive correlation between number of fruit and weight of fruit per tree.

Effect of pre-storage treatment with hormic dose of UV-light and ripening on the changes in topography and fine structure of postharvest tomato fruit during storage was studied by scanning electron microscopy (SEM). Both ripening and UV-treatment induced significant structural modifications in tomato fruit surface. Flattening of cellular mounds associated with normal ripening process was more intense with UV-treatment, and the fruit surface was also more wrinkled with treatment. The formation of an operculum over broken trichomes was a common feature of ripened control fruit, while this structure was incompletely formed in the treated fruit. Surface of senescent control fruit was characterized by the presence of an amorphous epicuticular wax, which was quasi-absent on UV-treated fruit. Surface colonization of UV-treated fruit by Botrytis cinerea was also different from untreated control. Colonization was sparse on the treated fruit, although direct cuticle penetration as well as penetration through damaged trichomes was observed in both cases. Fewer adhesion structures (appressoria) were observed on UV-treated fruit than on non-irradiated control, suggesting that structural modification of the epicuticular wax induced by UV may be a factor affecting the ability of B. cinerea to attach to the treated fruit surface. This study shows that UV-treatment causes alteration in the amount of epicuticular wax and its ultrastructural arrangement, presumably due to changes in its chemical composition. These changes could affect light reflectance characteristics of the fruit surface, and possibly increase transpiration loss leading to changes in fruit appearance. Another consequence of UV-induced physical and chemical modifications of tomato fruit surface could be an improved ability of the tissue to resist infection by B. cinerea. However, the reduced colonization of the UV-treated fruit by the pathogen cannot be attributed solely to changes in surface topography.

Goldenberries (Physalis peruviana L.) were harvested at four different maturity stages: immature green (IG), mature green (MG), yellow (Y) and orange (OR). Fruit were treated or not with 1-methylcyclopropene (1-MCP) at 25°C for 20h and then kept at 20°C for 8d. 1-MCP gas concentrations used were 0, 0.5 or 5μLL⁻¹. Application of 1-MCP delayed the onset of the ethylene climacteric in IG and MG fruit in a dose-dependent fashion, and transiently decreased ethylene production in Y and OR fruit. 1-MCP application transitorily decreased the respiration rate in MG fruit and, to a lesser extent, in IG and Y fruit. In contrast, 1-MCP-treated OR fruit displayed higher respiration rates than control fruit throughout the experimental period. Fruit treated with 5μLL⁻¹ 1-MCP showed for 6d average CO₂ production levels approximately 41% higher than those of control fruit, with a respiration rate up to 76% higher on day 4. The hue angle was higher in 1-MCP-treated Y goldenberries than in control fruit for 8d but differences between MG treated and untreated fruit were recorded only at the end of the experiment. In contrast, no differences were detected in IG and OR fruit. 1-MCP-treated fruit were not consistently firmer than untreated fruit during storage. Also, 1-MCP had no effect on soluble solids or ascorbic acid contents. 1-MCP application did not prevent decay in OR fruit but reduced its incidence thus suggesting that it may influence pathogen infection and development in ripe goldenberries.

This study investigates the influence of a commercial product, Biopron®, consisting of the bacteria Azospirillum brasilense and Pantoea dispersa on sweet pepper fruits (Capsicum annuum L.) under limited N supply. When the N supply was reduced from 12 (control) to 7mmolL⁻¹, the concentration of total-N in the fruits was significantly reduced in both inoculated and non-inoculated plants. The N supply or inoculation did not affect the dry matter content or fruit firmness, but non-inoculated fruit with low N showed a decrease in pericarp thickness and a significant increase in the color parameter a * compared with the control. Under limited N, inoculation increased the concentration of citric, ascorbic and succinic acids in green fruit compared with non-inoculated fruit, which showed lower values than control fruit. At a later (yellow) stage of development, only succinic acid showed a response to inoculation. Fruit peroxidase (EC 1.11.1.7) activity in fruit of inoculated plants was lower than that observed for non-inoculated fruit grown at both high- and low-N. In contrast, in yellow fruit, total phenolic compounds were increased under N limitation, with no inoculation effect. Our study shows that the effect of plant associative bacteria is not directly related with the increased potential availability of nutrients for uptake, especially for fruit quality characteristics.

The potential of using Rhodotorula glutinis alone or in combination with hot water for the control of postharvest blue mold decay of pear fruit, and their effects on postharvest quality of fruit was investigated. Spore germination of Penicillium expansum was inhibited by hot (46°C) water. Both hot water for 10-20min and R. glutinis, as stand-alone treatments, reduced the incidence of blue mold decay, but complete control was not achieved by either treatment. However, a combination of hot water treatment and R. glutinis completely controlled decay of inoculated fruit. In addition, the combination of hot water treatment with R. glutinis on naturally infected, intact fruit, reduced decay from 66.7% in the control fruit to 13.3% after 15 days at 20°C, and from 46.7 to 6.7% after 4°C for 60 days followed by 20°C for 15 days. None of the treatments impaired fruit quality. The combination of hot water and R. glutinis could be an alternative to synthetic fungicides for the control of postharvest blue mold decay on pears.