Food Technology
Rahman Yousefi; Mohammadreza Pourghayoumi; Seyyed Samih Marashi; Ali Ghasemi
Abstract
IntroductionDate palm (Phoenix dactylifera) is one of the most important horticultural products in arid and semi-arid regions of Iran. One of the factors affecting the quality and nutritional elements of date fruit- as an important and strategic fruit in the country, with high nutritional and health ...
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IntroductionDate palm (Phoenix dactylifera) is one of the most important horticultural products in arid and semi-arid regions of Iran. One of the factors affecting the quality and nutritional elements of date fruit- as an important and strategic fruit in the country, with high nutritional and health value- is the proper use of different nutritional elements during its growth and fruiting period. There are many reports of the negative effects of salinity on dates, both in the vegetative and reproductive growth stages. The osmotic effects limiting the absorption of water and nutrients, the specific effect of chlorine and sodium ions, nutritional imbalance and preventing the physiological processes and metabolism of nutrients and the use of high energy in osmotic regulation are some of the negative effects of salinity stress. Salinity stress negatively affected date fruit quality. Silicon is one of the essential nutrients that plays an important role in the growth and development of plants. Silicon reduces the adverse effects of abiotic stresses such as drought and salinity by affecting on the leaf and stem growth, and other plant mechanisms. Therefore, the aim of this study was to investigate the effect of foliar application of silicon on some qualitative characteristics and nutrient elements content of date fruit grown under high salinity soil. Materials and Methods This research was conducted in a randomized complete block design with 7 treatments and 3 replicates in two consecutive years. Silicon foliar spray treatments consisted of: control or no application of foliar spraying (T1), foliar spraying with a concentration of 0.1% in two stages (T2), foliar spraying with a concentration of 0.1% in three stages (T3), foliar spraying with a concentration of 0.2% in two stages (T4), foliar spraying with a concentration of 0.2% in three stages (T5), foliar spraying with a concentration of 0.3% in two stages (T6) and foliar spraying with a concentration of 0.3% in three stages (T7). The treatments were repeated in two consecutive years, and in each fruiting season, fruit quality characteristics including total soluble solids (TSS), acidity (TA), pH and total sugar content were measured. Total sugar was measured according to Iran's national standard method No. 2685 (ISIRI, 2007). The concentrations of potassium, calcium, iron and zinc were also measured at the end of the second year of the experiment. Fruit quality characteristics and concentration of fruit nutrients were measured and statistically analyzed. Results and DiscussionFoliar application of silicon fertilizer significantly increased the TSS of ‘Barhee’ date fruits while it decreased the pH of fruit juice. The lowest amount of total soluble solids was observed in T1 treatment at the rate of 63.69% and the highest amounts of fruit soluble solids were recorded in T5 and T6 treatments with values of 70.07% and 68.59% respectively. Fruit acidity and total sugar were not affected significantly by foliar application of silicon. The application of silicon significantly increased the contents of potassium, calcium, iron and zinc in date fruit, but it had no significant effect on the concentration of phosphorus in the fruit. The highest concentration of fruit potassium was observed in the T6 treatment (spraying with 0.3% silicon solution in two stages) at the amount of 1.54%. The lowest values of potassium concentration were observed in T3, T2 and T1 treatments with values of 0.89%, 1.01% and 1.06% respectively. Overall, Foliar application of silicon fertilizer can improve the quality characteristics and nutrient concentration of date fruit under salinity stress conditions. Among all the treatments, foliar application of silicon fertilizer with a concentration of 0.3% in two stages (three weeks before pollination and at the end of the Hababook stage) improved quality characteristics and the nutrient elements of ‘Barhee’ date fruit under high salinity soil.
