Rouhollah - Karimi; Seyed Mehdi Mirbagheri; Maryam Davtalab
Abstract
Raisins are good sources of bioactive compounds with beneficial effects on human health. Mineral nutrition is one of the main viticultural practices affecting grape and raisin phytochemical compositions. In this study, the effect of preharvest foliar application of potassium (K2SO4; 0, 1.5 and 3%) and ...
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Raisins are good sources of bioactive compounds with beneficial effects on human health. Mineral nutrition is one of the main viticultural practices affecting grape and raisin phytochemical compositions. In this study, the effect of preharvest foliar application of potassium (K2SO4; 0, 1.5 and 3%) and iron (Fe-EDDHA; 0, 0.5 and 1%) was evaluated on some nutritional and biochemical properties of raisins produced from ripped ‘Red Sultana’ grape (Vitis vinifera L.). The experiment laid on a factorial arrangement of variables using a completely randomized block design. The highest soluble sugars of fructose and glucose were related to raisin produced from the vines treated with 3% potassium in combination with 0.5% iron fertilizers. However, 3% K2SO4-treated vines in combination with 1% Fe- EDDHA showed a considerable increase in raisin sucrose and also putrescine concentration. The raisin organic acids of succinic acid, fumaric acid, citric acid, and malic acid increased significantly in treated vines with both fertilizers at final doses; however, tartaric acid showed the highest amount in 3% potassium in combination with 0.5% iron treatments. The vines treated with a high level of potassium in combination with moderate level of iron produced raisin with the highest phenolic acids of kaempferol, quercetin, chlorogenic acid and resveratrol and also showed the lowest polyphenol oxidase activity. Furthermore, raisin cinnamic acid, rutin and catechin concentration showed a peak in vines sprayed with a high level of potassium and iron and also most anthocyanidins such as petunidin-3-glucoside, peonidin-3-glucoside, cyanidin-3-glucoside and delphinidin-3-glucoside reached their highest concentration by this treatment. Likewise, the highest antioxidant capacities (measured by FRAP, DPPH and ABTS methods) were achieved in 3% potassium–treated vines in combined with iron at a moderate level. In conclusion, results indicated that preharvest application of potassium and iron are highly effective to improve the Red Sultana raisin bioactive compositions.
Zohre Rohi Vishekaii; Ali Soleimani; Akbar Hasani; Mahmood Ghasemnezhad; Karamatollah Rezaei; Somaye Kalanaky
Abstract
Different sources of nitrogen fertilizers are being used in olive orchards, of which urea is widely used by olive growers. However, nano-chelated nitrogen (nano-N) is a newly found feature of the fertilizer with very little known information. In the current research, the impact of foliar spray of two ...
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Different sources of nitrogen fertilizers are being used in olive orchards, of which urea is widely used by olive growers. However, nano-chelated nitrogen (nano-N) is a newly found feature of the fertilizer with very little known information. In the current research, the impact of foliar spray of two nitrogen sources; urea (U) and nano-N on oil content and quality of olive cv. ‘Zard’ during two consecutive seasons were investigated. The olive trees were sprayed with 2.21 g (U1) and 2.95 g (U2), and 6 g nano-N1 and 8 g nano-N2 at several phenological stages of olive tree. The detailed observations showed that U1 significantly increased fruit yield. Monounsaturated fatty acid and the ratio of oleic acid to linoleic acid were increased by the nitrogen treatments, especially with nano-N2, whereas it decreased in the case of saturated fatty acid and polyunsaturated fatty acids. The application of both fertilizer sources improved the leaf mineral compositions as well as the oil quality such as free fatty acids, peroxide activity, K232 and K270 extinction coefficients, the chlorophyll and carotenoid pigments. Total phenolic content of the oil in olive trees sprayed with urea was lower than those treated with nano-N. In contrast, the oil antioxidant capacity was high in those trees treated with nano-N. Overall, the results showed that nano-fertilizer, especially nan-N2 treatment rather than urea, is an effective approach to improve oil quality.
Tahereh Raiesi; Bijan Moradi; Javad Fatahi Moghadam
Abstract
Kiwifruit requires a high quantity of nutrients that must be supplied through fertilization to obtain an optimum yield on a sustainable basis. This research was conducted to evaluate different fertilization methods including broadcast application (as control), deep placement of the fertilizer and fertigation, ...
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Kiwifruit requires a high quantity of nutrients that must be supplied through fertilization to obtain an optimum yield on a sustainable basis. This research was conducted to evaluate different fertilization methods including broadcast application (as control), deep placement of the fertilizer and fertigation, alone or in combination with foliar application and their effects on the yield, leaf mineral contents, and some quality properties of kiwifruit (A. deliciosa cv. Hayward). Results showed that fertilization methods had a significant effect on yield and the highest level of yield (76 Kg tree-1) was obtained in the combination of fertigation with foliar spray. In addition, foliar application significantly increased leaf mineral contents of kiwifruit in all treatments. Furthermore, the fertilization method had significant effects on phenol, ascorbic acid contents, and antioxidant capacity of fruits. The highest levels of antioxidant (70.9%), phenol (103.6 mg 100g-1), and ascorbic acid (54.2 mg 100 g-1) in fruits were recorded in ‘soil application’ method. Total soluble carbohydrate and starch contents of the fruits were reduced following foliar nutrition in all treatments. However, foliar nutrition significantly increased fruit crude protein. In conclusion, based on obtained results, fertilization method directly influenced the yield and leaf mineral status and indirectly influenced the fruit chemical composition of Hayward kiwifruit. In fact, the supplemental foliar application reduced some fruit quality attributes (lower antioxidant activity and carbohydrate content) but enhanced the yield of kiwifruit.
