الفهرس 
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Abstract
Experimental work:- This investigation aimed to study the effect of potassium sulphate and Salicylic acid (SA) used as separately or in combination on the quality of ’’Balady’’ orange fruits during storage in room temperature. Orange fruits were collected at maturity stage from the orchard of Pomology Department, Faculty of Agriculture, Assiut University throughout two successive seasons of 2015 and 2016. Harvested fruits were brought directly to the laboratory in the same Faculty The fruits were subjected to the following treatments:- 1- Control (untreated) T1. 2- Potassium sulphate (48%) T2. 3- Salicylic acid 4 mM/l T3. 4- Potassium Sulphate (48%) and SA (4 mM/l) T4. Some physical and chemical properties were measured as follows:- A - Physical properties:- Fruit weight (g), Weight loss (%), pulp weight (g) and Fruit juice content %. B - Chemical properties: - Total soluble solids percentage (T.S.S %), total acidity %, T.S.S/acid ratio, reducing and total sugars and ascorbic acid content (mg/100ml). The results could be summarized as follows:- A- Physical properties:- 1- Weight loss :- Generally, the weight loss % significantly increased with the prolonging of storage period in the two successive seasons. At the end of storage the highest values of weight loss% were found in control fruit while the lowest values were recorded by SA treatment in the two tested seasons, respectively. 2- pulp weight :- The percentage of fruit pulp in untreated orange fruits and fruits treated with potassium sulfate (pre-harvest) or salicylic acid gradually decreased during the period of storage in both seasons. The treatment of salicylic acid significantly reduced the percentage of loss in the pulp weight in the two successive seasons, compared to control. At the end of the storage period (after 50 days) using salicylic acid alone had the highest effect on reduction the loss of the fruit pulp weight. On the other hand the highest value of pulp weight loss% was found in control fruit. 3- Juice content %:- Gradually and significantly reduction of juice content % in Balady orange fruit was with found progress the storage period during both investigated seasons. At the end of storage period the lowest value of juice content % were found in the untreated fruits during 2015 and 2016 seasons, In addition the highest juice percentage were recorded in orange fruits treated with SA+K followed by SA alone. B - Chemical properties:- 1- T.S.S% :- T.S.S content significantly increased with extending the storage period and reached its maximum values at the end of storage. Moreover the highest values of T.S.S percentage were recorded in the untreated fruits (control), while the lowest values were measured in the treated fruits with SA during both 2015 and 2016 seasons. This could be due to the higher water loss percentage of control fruits as compared with other treatments. 2- Total acidity %:- Same trend during both seasons was found, which the content of acidity gradually decreased with storage period progress and reached its minimum values at the end of storage. All treatments significantly increased the acidity content comparing with control, so the untreated fruits had the lowest values of acidity at the end of storage period during both 2015 and 2016 seasons. The treated fruit with (SA+K) contained the highest acidity percentage in the first season while the fruits treated with SA had the highest acidity content in the second one. 3- TSS/Acid Ratio:- With the prolonging of storage period increasing the percentage of TSS% and reduction the acidity % led to increasing TSS/ acid ratio. At the end of storage in the both seasons the highest reduction of TSS/acid ratio was noted by T3 and the highest values were obtained by control in the both seasons and there were significantly differences between all treatments and control in the two successive seasons. 4- Ascorbic acid content (mg/100ml):- Ascorbic acid content of fruits by all treatments gradually decreased with prolonging the storage period during both tested seasons. Significant differences were found between the treatments and control in both successive seasons (2015 and 2016). Were found at the end of storage period, the lowest values of ascorbic acid % were found in control fruits while the highest values were recorded by SA+ K treatment during both seasons. 5- Reducing sugar %:- The percentage of reducing sugars gradually increased in all treatments during the two experimental seasons (2015-2016) under the storage conditions at room temperature. The highest values of reducing sugar were recorded in the fruits treated with potassium sulfate at the end of storage period, while the lowest values were found in the fruits treated with salicylic acid. 6- Total Sugars %:- The percentage of total sugars increased gradually in all treatments with the progress of storage period during the two experimental seasons (2015-2016). The highest values of total sugar were measured in the fruits treated with potassium sulfate at the end of storage period, while the lowest values were found in the fruits treated with salicylic acid. Recommendation:- This study proved that the possibility of storing the orange fruits still about 50 days at room temperature by spraying it by potassium sulfate (before harvest) combination with the use of salicylic acid (after harvest) or used of salicylic acid (after harvest) alone with maintain the fruit quality during storage at room temperature.