Postharvest physiology
Majid Rahemi; Mohammad Hassan Nazaran; Samira Abolghasemi; Sahar Sedaghat; Maryam Zare
Abstract
Introduction
Low temperature storage is the most important method used to preserve harvested products. Keeping products at low temperatures, above the freezing point up to 10 degrees Celsius, can cause frost damage in fruits and vegetables, especially tropical and subtropical products. The use of heat ...
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Introduction
Low temperature storage is the most important method used to preserve harvested products. Keeping products at low temperatures, above the freezing point up to 10 degrees Celsius, can cause frost damage in fruits and vegetables, especially tropical and subtropical products. The use of heat treatments as safe, organic and alternative physical methods is increasing, these treatments are used to maintain the quality after harvesting and also to prevent frostbite of garden products. Also, one of the recommended methods to reduce fruit waste is to increase the calcium concentration of the fruit by using calcium solutions. Calcium is one of the most important mineral elements that is involved in determining the quality of the fruit and its shelf life. Studies conducted on the use of nano fertilizers in some species of fruit trees has shown their potential role in improving the yield of the product and the physical and chemical properties of the fruitThis study was conducted to investigate the effect of postharvest treatments of calcium chloride and nano chelated calcium fertilizers on chilling injury and physiological characteristics of local orange fruits stored at 2 ±0.5° C and 85% relative humidity for 60 to 120 days.
Materials and Methods
In this research, orange fruits of the local cultivar Citrus sinensis at the stage of commercial maturity based on the taste index (10TSS/TA⋍) were prepared from Darab city of Fars province and transferred to the Physiology Laboratory of Horticultural Sciences Department of Shiraz University. Then the fruits were disinfected with 2% sodium hypochlorite and washed with distilled water. Treatments included calcium chloride and nano chelated calcium fertilizers at different concentrations of zero, 3 and 6 dissolved in cold water (20°C) and hot water at 45 °C for 25 and 15 min, respectively. Sampling was done on days 60 and 120. To simulate shelf life conditions, before measuring the parameters, the fruits were kept at laboratory temperature for two days. In this research, the changes in fruit tissue firmness, freezing index, weight loss percentage, soluble solids, total acidity, ascorbic acid, ion leakage, potassium ion leakage, malondialdehyde, calcium content of fruit skin and flesh, fruit color, catalase enzymes and peroxidase were measured. Data analysis was done using SAS software version 4.9 and comparison of averages was done by LSD test at 5% probability level.
Results and Discussion
There was a significant difference between nano chelated calcium and calcium chloride in calcium enrichment in pulp and fruit skin Calcium chloride and nano chelated calcium treatments dissolved in hot water reduced weight loss, soluble solids content, acidity, ascorbic acid, ion leakage and malondialdehyde and the activity of the antioxidant enzymes catalase and peroxidase. Nano chelated calcium increased calcium content by 44% in fruit skin and up to 41% in fruit pulp compared to calcium chloride. Nano chelated calcium 3 and 6 % showed more stability in fruit weight (159 and 400%, respectively) compared to calcium chloride after two months of storage. After 60 and 120 days of storage, the content of ascorbic acid in fruits treated with 6 nano chelated calcium was 73% higher than calcium chloride. Nano chelated calcium 3 % compared to calcium chloride prevented 39.6 of potassium ion leakage during 60 days of storage. The amount of ascorbic acid in the 3% and 6% nano calcium treatment and the tissue hardness in the 3% nano calcium chelate treatment after two months of storage were estimated to be higher than the control and calcium chloride. Calcium nano chelate 6% improved the calcium content of fruit flesh and skin due to increased permeability. Warm water pretreatment with calcium compounds is an efficient and recommendable treatment for the preservation of orange fruits in cold storage conditions due to the improvement and reduction of the severity of the increase in indicators related to the occurrence of frost damage in the skin of fruits.
Conclusion
One of the primary concerns during storage is the loss of fruit weight. Calcium nano chelate, in comparison to the control and calcium chloride treatments, exhibited the least weight loss over the two months of storage. This is attributed to the critical role of calcium in influencing the shelf life of fruits. It was observed that immersing fruits in calcium compounds dissolved in hot water and utilizing 6% nano chelated calcium had a significant positive impact on enhancing and preserving the quality of orange fruits during cold storage.
Maryam Zare; Barat Ali Fakheri; Sara Farokhzadeh
Abstract
Introduction: The recognition of salt tolerant plants is important as a result ofincreasing saline lands in Iran and world. Cultivation of plants in hydroponic environment is a reliable and economical method in order to select the salt tolerant plant. Salt stress can effect on plant growth and development ...
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Introduction: The recognition of salt tolerant plants is important as a result ofincreasing saline lands in Iran and world. Cultivation of plants in hydroponic environment is a reliable and economical method in order to select the salt tolerant plant. Salt stress can effect on plant growth and development by ion toxicity, ionic disturb the balance and osmotic potential. Lettuce is one of the most important vegetable crops. This plant is one of the most important leafy vegetables which is used for salad and fresh marketing, also some types of this vegetable is used in baked type. The aim of this study was to investigate the genetic diversity of lettuce genotypes undersalt stress in the hydroponic system.
Materials and Methods: To assess response of lettuce seedlings to salt stress, a factorial experiment was conducted in a completely randomized design with three replications at Biotechnology Research Institute for hydroponic cultivation of Zabol. In this experiment, the effects of three salinity levels (0, 2 and 4 dS/m) on morphological characteristics of 15 lettuce genotypes were evaluated. The seeds were sterilized for ten seconds in ethanol 96% and then 15% sodium hypochlorite solution for 50 seconds, then rinsed several times with distilled water, then disinfected seeds were cultured in plastic pots containing coco peat and perlite. After …days plants were transferred to hydroponic system containing Hoagland solution. Collected data were analyzed and means comparisons were made using LSD by SAS software.
Results and Discussion: The results showed that salinity has a significant effect on seedling growth of lettuce genotypes (p≤0.01). significant difference between salinity levels and genotype were observed for all traits. Interaction of genotype and salinity for all the traits except root length, plant length and leaf were significant at 1%. Based on the results, the greatest root length was belong to Esfahan Varzaneh leafy lettuce and Romaine lettuce long green Teresa genotype, respectivly. Increasing salinity led to significant reduction (p≤0.01) in the plant length lettuce in all genotypes. Root and plant fresh weight lettuce genotypes were significantly (p≤0.01) influenced by different levels of salinity. The greatest amount in root and plant fresh weight lettuce genotypes were obtained in the control treatment and the lowest amount at the level of 4 dS/m. Root and plant dry weight lettuce genotypes were significantly (p≤0.01) influenced by the salinity. Root and plant dry weight decreased with increasing salinity. So that the greatest amount of root and plant dry weight lettuce genotypes were obtained in control treatment and the lowest amount at the level of 4 dS/m.. The results showed that root and plant length ,root fresh and dry weight, plant fresh and dry weight and leaf length and width reduced with increasing salinity. The clustering pattern the genotypes were grouped into 3 clusters based on their charachters at 4 dS/m salinity. The first cluster were placed in salt tolerant groups, while the other genotypes were clustered into moderately tolerant cluster. Romaine lettuce long green Teresa genotype was placed in salt-tolerant group and Lettuce Everest, Lettuce May Queen, Curly endive hair angel, Cabbage Milan Aubervilliers and Romaine lettuce long blonde Galaica were placed in salt-sensitive group.