جستجوی مقالات مرتبط با کلیدواژه « سرمازدگی » در نشریات گروه « زیست شناسی »

In order to investigate the effect of using salicylic acid, antifreeze and soybean oil, on the cold resistance of the flower of the sweet cherry tree cultivar "Siah Tak Daneh Mashhad", a factorial experiment in the form of a randomized complete block design with 3 factors (salicylic acid: zero, 1.5 and 3 mM), (natural antifreeze: zero, 2.5 and 5 per 1000) and (soybean oil: zero, 2.5 and 5 per 1000) and in 4 repetitions was conducted in a commercial garden located in Sarein city in 2018 and 2019. The results of the variance analysis of the data showed that the three-way effects of factors on proline are significant at the 5% probability level and on soluble carbohydrates and protein at the 1% probability level. The highest amount of proline (70.85% compared to the control) was observed in the treatment of salicylic acid foliar spraying 3 mM along with soybean oil (5/1000) and Thiofer antifreeze (5/1000 foliar treatment). The bilateral effects of salicylic acid and soybean oil on glycine betaine were different at the 1% probability level and on the activity of the catalase enzyme at the 5% probability level. The highest accumulation of glycine betaine (27.27% compared to the control) and also the highest activity of the antioxidant enzyme catalase (36.84% compared to the control) in salicylic acid (1.5 mM) foliar treatment with soybean oil (5 in 1000) were obtained. According to the observations of this research, it can be concluded that the use of salicylic acid foliar treatment (3 mM) along with soybean oil (5/1000) and 5/1000 foliar treatment of Thiofer natural antifreeze in flower buds. It is a suitable solution to increase the cold resistance indices of cherries against cold stress.

This study was conducted to investigate the frost status in the 11 commercial cultivars, three newly introduced cultivars and two genotypes of olives. After the occurrence of frost at the Tarom region of Zanjan province in February 2019, three trees from each cultivar were selected. Frost symptoms were recorded based on observational indices. Gas exchange traits (stomatal conductance, transpiration and photosynthesis rate), proline content, pigments and leaf nutrients were measured. Evaluation of frost severity based on observational indices revealed that there was a large difference between cultivars to frost tolerance. Principal component analysis differentiated susceptible cultivars and genotypes to frost. Zard, Grossane, Abou-Satl, Konservolia, Picual and Cornicabra cultivars were grouped as frost tolerant cultivars. Direh, Meshkat, Amin and Koroneiki cultivars were introduced as completely cold sensitive. Among the many evaluated traits for screening olive cultivars and genotypes, proline content and pigment (SPAD index) were identified in discrimination as the most important distinguishing traits of olive cultivars in terms of cold tolerance.

The optimum temperature storage of anthurium flowers is 12.5–20 ºC because they are very sensitive to chilling injury (CI). In this study, the effects of 0, 1, 5, 10, 15 and 20 mM γ-aminobutyric acid (GABA) treatment applied by preharvest spraying or postharvest stem-end dipping (15 min at 20 ºC) on CI of anthurium flowers (cv. Sirion) stored at 4 ºC for 21 days was investigated. CI symptoms were accompanied by spathe browning and increase in electrolyte leakage as well as malondialdehyde (MDA) content. GABA treatment at 1 and 5 mM by pre and postharvest treatment, respectively, delayed spathe browning and increases in electrolyte leakage and MDA accumulation. Also, GABA treatments delayed decrease in total anthocyanins leading to significantly higher total anthocyanins content in GABA treated anthurium cut flowers during storage at 4 ºC for 21. GABA treatment at 1 and 5 mM by pre and postharvest treatment, respectively, delayed decrease in spathe RWC. Also, glycine betaine (GB) content in anthurium cut flowers treated with GABA was significantly higher than control flowers during storage. These results showed that GABA treatment at 1 and 5 mM by pre and postharvest treatment, respectively, ameliorated chilling injury of anthurium cut flowers, which can be used as promising technology at commercial scale.

To develop an effective technique to reduce chilling injury (CI) in tomato fruit, the effects of treatments with 0, 3 and 6 µM brassinosteroids (BRs) on chilling injury, electrolyte leakage, contents of malondialdehyde, proline and total phenol and activities of phospholipase D (PLD), lipoxygenase (LOX) and phenylalanine ammonia-lyase (PAL), were investigated in tomato fruits stored at 1°C for 21 days. Treatments with BRs, especially at 6 µM, significantly ameliorated chilling injury, reduced electrolyte leakage and malondialdehyde content and increased proline content. PLD and LOX activities in fruits treated with BRs were significantly lower as compared with the control fruits. Also, fruits treated with BRs exhibited significantly higher PAL activity and total phenol content. These results suggest that that brassinosteroids has potential postharvest technology in ameliorating the chilling injury in tomato fruit.

Tomato fruit harvested at mature green stage and treated with salicylic acid at different concentration (0، 1 and 2 mM) and analyzed for chilling injury، electrolyte leakage، malondialdehyde، proline and total phenol contents and phospholipase D، lipoxygenase and phenylalanine ammonia-lyase activities during cold storage. Phospholipase D and lipoxygenase activities were significantly reduced by salicylic acid treatment. Compared with the control fruit، salicylic acid treatment alleviated chilling injury، reduced electrolyte leakage، malondialdehyde content and increased proline content. Salicylic acid application had no significant effect on total phenol content but phenylalanine ammonia-lyase activity was significantly reduced in treated fruits. Our result suggest that the reduce activity of PLD and LOX، by salicylic acid may be a chilling tolerance strategy in tomato fruit. Inhibition of PLD and LOX activity during low temperature storage could ameliorate chilling injury and oxidation damage and enhance membrane integrity in tomato fruit.