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The effect of exogenous salicylic acid (SA) on the vase life of cut rose flowers was investigated. 'Yellow Island' roses were obtained from a commercial grower. The roses were pulse treated with SA (0, 50, 100, 150, 200 mg l-1) for 18 hours. Com­pared to the control treatment (DW), the greatest delay in senescence was obtained in cut roses treated with 150 mg l-1 SA. With this treatment, flower vase life was dou­bled. The physiological characteristics such as protein concentration, lipid peroxida- tion (MDA) level and enzyme activity such as lipoxygenase (LOX), superoxide dis- mutase (SOD) and peroxidase (POD) were measured only in the control (DW) and those kept in a solution of 150 mg l-1 salicylic acid (SA) for over 8 days of vase life. Degradation of protein and accumulation of MDA during vase life was shown to be suppressed by 150 mg l-1 SA. The activity of LOX and POD gradually increased with progressing flower senescence, while SOD activity declined. The flowers which had been pulsed with SA exhibited lower LOX and POD activity, and a higher activity of SOD. Overall, the results suggest that SA increases vase life by improving the anti- oxidant system and reducing oxidative stress damages during rose flower senescence.
The changes in the antioxidant enzymes activity, total protein and proline content and their correlations with freezing tolerance (FT) (expressed as LT₅₀) were investigated at 11 different olive cultivars at cold-acclimation (CA, in February) and non-acclimation (NA, in August) stages. Leaf samples were collected from each cultivar and were divided into two groups. The first group was immediately frozen in liquid nitrogen for further biochemical analysis. The second ones was subjected to different freezing temperatures (-5, -10, -15 and -20°C) for 10 h, in order to determine their FT. The unfrozen control samples were kept at 4°C. The results showed that Fishomi, Mission and Shengeh were the most freezing tolerant among other cultivars. In contrast, Zard, Manzanilla and Amigdalolia were the most sensitive ones. The cold acclimation enhanced the activities of superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), catalase (CAT), polyphenol oxidase (PPO) and total protein content. However, proline content and phenylalanine ammonia-lyase (PAL) activity did not change or even decreased slightly at CA stage, compare to those samples at NA stage. It was found that LT₅₀ to be closely correlated to POD, CAT, and PPO activity at CA and NA stages. Overall, higher leaf POD, CAT, and PPO activity could be used as important selection criteria in screening tolerant olive cultivars for cold zone climatic.
Despite the importance of calcium in many fruit species and the effects of calcium application, there is little or no reliable information on the effect of CaCl2 spray at different fruit development stages on the fruit mineral nutrient content during the growing season and at harvest. Therefore, this study has been conducted to evaluate the effect of calcium chloride (CaCl2, 15 g L-1) spray at different fruit development stages on the accumulation Ca and other macronutrients in cv. Hayward kiwifruit grown at two locations. In order to find the absorbality of Ca at different spraying times, fruits were harvested 7 days after a Ca treatment. Additionally, the mineral composition of kwifruit was determined at the stage of harvest ripeness. The results showed that the absorbality of Ca by kiwifruit from Ca spray decreased significantly with the progressing fruit development. The highest fruit Ca content was found when the fruit plants were sprayed at 35+80 DAFB and 35+80+120 DAFB, irrespectively of the location of an orchard. At a later Ca spraying application, the N content in kiwifruit significantly decreased, but the K and Mg content slightly increased. In contrast, the K/Ca, N/Ca, Mg/Ca and (K+Mg)/Ca ratios of CaCl2 sprayed fruits was lower than in the control and the ratio values were more balanced in the Ca treated fruit than in the control. Overall, three CaCl2 (15 g L-1) sprays could effectively improve the fruit quality by balancing the Ca ratio to other macronutrients. Therefore, Ca spray treatments could be a recommended treatment in growing cv. Hayward kiwifruit.
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