Ali Salehi Sardoei; Mehdi Sharifani; Mostafa Khoshhal Sarmast; Mahmoud Ghasemnejad
Abstract
Citrus species are comprised of susceptible plants that can barely tolerate freezing temperatures. To determine the relationship between cold stress tolerance (LT50) and some important physiological traits, four commercial citrus cultivars of citrus species were studied. These were Citrus unshiu, Citrus ...
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Citrus species are comprised of susceptible plants that can barely tolerate freezing temperatures. To determine the relationship between cold stress tolerance (LT50) and some important physiological traits, four commercial citrus cultivars of citrus species were studied. These were Citrus unshiu, Citrus sinensis var. ‘Thomson navel’, Citrus paradisi var. ‘Star Ru by’ and Citrus limon var. ‘Lisbon’. Assessments of cold-stress tolerance were carried out at 4, -4 and -8 °C. Ultimately, the results showed that the Japanese mandarin and ‘Thomson navel’ had the highest stress tolerance (LT50). Citrus unshiu tolerated cold stress up to -8.4 LT50. The correlation coefficient demonstrated that significant, positive correlations were observed between several pairs of attributes, i.e. LT50 and total flavonoids, chlorophyll a and chlorophyll b, carotenoids and chlorophyll a, chlorophyll b and total chlorophyll, relative moisture content and malondialdehyde, as well as glycine betaine and catalase. According to the regression coefficient, a change of one unit in lipid peroxidation caused a decrease of 1.9238 units and 5.9615 units in LT50 at +4 and -4 °C, respectively. While commercial citrus cultivars were selected for cold-tolerance and other traits, the efficiency of cold-tolerance correlated more with carotenoid content, chlorophyll content and lipid peroxidation, considering the assessments at particular temperatures.
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.
Reza Partiya; Reza Fotouhi Ghazvini; Reza Fifaei; Mahmood Ghasemnezhad
Abstract
Hypoxia is a potential threat to various horticultural cropsin lands prone to flooding. Citrus is mostly known as a sub-tropical crop that is often exposed to environmental stresses. In order to evaluate response of six different citrus genotypes, including sour orange, rough lemon, Trifoliate orange, ...
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Hypoxia is a potential threat to various horticultural cropsin lands prone to flooding. Citrus is mostly known as a sub-tropical crop that is often exposed to environmental stresses. In order to evaluate response of six different citrus genotypes, including sour orange, rough lemon, Trifoliate orange, Troyer citrange and two local genotypes labeled; CRC1 and CRC2 to flooding conditions, an experiment was carried out in factorial experiment based on a completely randomized design with two treatments including flooded and control plants and three replications. Flooding stress significantly decreased leaf chlorophyll content, and plant total fresh and dry weights (P≤ 0.05). Flooding caused a significant increase in foliar concentration of proline in CRC1 and CRC2 (P≤ 0.05). Guaiacol peroxidase activity was significantly increased in Trifoliate orange. CRC2 and sour orange showed a significant increase in superoxide dismutase activity (P≤ 0.05). The longest survival period in continuous flooding condition was observed in Troyer citrange and Trifoliate orange (more than 60 days); while sour orange was the most sensitive genotype (less than 30 days). The best thriving genotype at the end of recovery period was Troyer citrange, while sour orange showed the least ability to re-establish. The results suggest that among the studied genotypes, Troyer citrange and Trifoliate orange are able to resist for longer periods of flooding exposure. Troyer citrange had the highest capacity to re-establish after being flooded to their critical surviving point. Furthermore, CRC2 tolerated anoxic condition and recovered more successfully than the other sensitive genotypes.
Hossein Meighani; Mahmood Ghasemnezhad; Davood Bakhshi
Abstract
The pomegranate fruit is a good source of bioactive compounds. The present study has investigated the biochemical and sensory characteristics of the arils of four Iranian commercial pomegranate cultivars namely Malase Shirine Saveh (MSS), Malase Torshe Saveh (MTS), Alak Shirine Saveh (ASS) and Agha Mohammad ...
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The pomegranate fruit is a good source of bioactive compounds. The present study has investigated the biochemical and sensory characteristics of the arils of four Iranian commercial pomegranate cultivars namely Malase Shirine Saveh (MSS), Malase Torshe Saveh (MTS), Alak Shirine Saveh (ASS) and Agha Mohammad Ali (AMA) for several developmental and ripening stages during 45–180 days after fruit set (DAFS). The results showed that the total soluble solids (TSS), individual and total anthocyanin concentrations, and color parameters including chroma and a* values significantly increased, in contrast, the total phenolic concentration and color parameters (L* and hue angle) gradually decreased during developmental stages. Six anthocyanin pigments were found responsible for the red color of pomegranate juice. The quantity and the quality of the anthocyanin pigments were different among the cultivars and the various developmental stages. The predominant anthocyanin pigment at all developmental stages in all cultivars was cyanidin 3,5-diglucosides. The maximum total phenolic concentration was recorded at 45 DAFS for all cultivars. The highest antioxidant activity was recorded at 45 DAFS, and gradually decreased until 135 DAFS. Similar decrease was observed in total phenolic and flavonoid concentrations. Notably, increasing of antioxidant activity at the late-developmental stage was due to induction of the flavonoids and anthocyanins accumulation.
Hossein Meighani; Mahmood Ghasemnezhad; Davood Bakshi
Abstract
Aril browning threatens production, consumption, and exports of pomegranates, because affected fruit cannot be externally distinguished from healthy fruit. This study compared the mineral, biochemical composition, and related enzyme activities in affected brown arils with healthy ones in ‘Malase ...
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Aril browning threatens production, consumption, and exports of pomegranates, because affected fruit cannot be externally distinguished from healthy fruit. This study compared the mineral, biochemical composition, and related enzyme activities in affected brown arils with healthy ones in ‘Malase Saveh’ pomegranates. The results indicated that concentrations of Cu in the aril and K, Mg, and Mn in the peel were higher in the healthy fruit than in the affected fruit. The total soluble solids, titratable acidity, total phenolics, total flavonoids, total anthocyanins, antioxidant activity, and color parameters (L*, a*, b*, hue, and chroma) decreased in the browned arils of pomegranates, whereas fruit respiration rate and acidity, peroxidase (POD), and polyphenol oxidase (PPO) enzyme activity were higher in the browned arils. No difference was found for phenylalanine ammonia lyase (PAL) activity. There were positive correlations between total anthocyanins and both color values and total phenols, and a negative correlation between PPO and POD activities was observed. Overall, the nutritional and functional value of the affected fruit is anticipated to be far less than that of the healthy fruit.