Postharvest physiology
Mahshid Ghafouri; Farhang Razavi; Masud Arghavani; Ebrahim Abedi Gheshlaghi
Abstract
Introduction Nowadays, the application of chemical compounds is limited due to their harmful effects on human and the environment health. The benefits of seaweeds as sources of organic matter and fertilizer nutrients have been known to agriculture for centuries, especially in coastal areas extracts ...
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Introduction Nowadays, the application of chemical compounds is limited due to their harmful effects on human and the environment health. The benefits of seaweeds as sources of organic matter and fertilizer nutrients have been known to agriculture for centuries, especially in coastal areas extracts of these seaweeds have been used for decades as foliar- and soil-applied treatments in crop production systems due to the presence of a number of plant growth-stimulating compounds. Unlike chemical fertilizers, extracts derived from seaweeds are biodegradable, non-toxic and non-hazardous to humans, animals and birds. Therefore, it is required to find a safe compound that is utilized in the postharvest technology of fruit and vegetables. Pre-harvest application of nutrient solutions such as seaweed increases the quality and quantity of crop and also enhance their storage life and marketability. Various researchers reported that aqueous extracts of seaweed increased the yield and quality of tangerine and orange, strawberry, grape, apple, and watermelon fruit. Thus, the aim of the current study was to investigate the effect of pre-harvest foliar application of Seaweed extract on quality and quantity values, antioxidant properties, and storage life of kiwifruits.Material and Methods This experiment was carried out on 10-year-old kiwifruit vines, in a commercial orchard located in Gilan Province. Vines were selected with uniform size in terms of growth, yield and fruit load, then sprayed with seaweed extract at four levels of 0, 1, 2 and 3 g.l-1 as a foliar spray and control vines only received water. Foliar spraying was performed in three stages, (110, 125 and 140 days after full bloom stage) and Tween 20 was used as a surfactant. This experiment was designed as factorial based on randomized complete block design with three replications. The fruits were harvested in November with soluble solids content (TSS) of 6.5-6.2% and then transferred to the post-harvest physiology laboratory of the University of Zanjan. The treated fruits were stored for 90 days at 1 ° C with 90% RH. Sampling was done at harvest time and after 30, 60 and 90 days of storage and some quantity and quality traits such as weight loss, tissue firmness, TSS, ascorbic acid, total phenol and flavonoids, antioxidant capacity and the activity of superoxide dismutase (SOD) and phenylalanine ammonia-lyase (PAL) enzymes were evaluated.Results and Discussion The ANOVA results showed that seaweed extract, storage time, and interaction of seaweed extract × storage time had a significant effect (p≤0.01) on evaluated traits. All treatments maintained the antioxidant capacity, total phenol and flavonoids content and PAL activity at a higher level compared with control. The amount of fruit tissue firmness, TA and ascorbic acid decreased by increasing the storage time, and at the third month of storage, the lowest amount was observed in the control fruit. Also, comparing the interaction of the mean of treatments and storage time showed that pH, weight loss, TA, TSS, antioxidant capacity, total phenol, flavonoids and PAL enzyme activity increased by increasing the storage time. At the end of the storage time, the highest level of TSS, weight loss and pH were observed in the control fruit. The lowest antioxidant capacity (48.14 %) was observed in the control treatment at harvest time and the highest antioxidant capacity was observed in 3 levels of brown algae extract treatment at the end of storage period. Comparison of means showed that at the first 30 days of storage, the highest PAL enzyme activity was observed in the treatment of 3 g / l of brown algae. PAL enzyme activity significantly increased after the experiment. At the end of storage period, the lowest PAL enzyme activity was observed in control fruit. Treatment of 3 g / l brown algae had higher PAL activity. PAL, as a key enzyme in phenylpropanoid metabolism, catalyzes the conversion of phenylalanine to trans-cinnamic acid, which is the first step in the biosynthesis of phenylpropanoids and leads to the production of secondary metabolites such as lignin, phytolaxoids, and flavonoids. The direct and positive relationship of this enzyme with the synthesis of phenols and flavonoids has been discovered in the fruits of blood orange, strawberry and blueberry. The results of the comparison of the mean showed that the total phenol and flavonoids increased by increasing the storage time. The lowest phenol (23 mg GAE.100 g-1 FW) was observed in control fruit at harvest and the highest (8.88 mg GAE.100 g-1 FW) content of total phenol was observed in 3 levels of brown algae extract at the third month of storage. Plants release phenolic compounds in response to some messenger compounds that play an important defense role. Studies show that there is a positive relationship between total phenol content and their antioxidant activity. Flavonoids are also polyphenolic compounds and are the most important secondary compounds of plants. Under oxidative stress, in plants, the activity of propanoid pathway increases, especially the pathway of flavonoids biosynthesis. Flavonoid compounds are abundant in plants and show antioxidant activity. Seaweed extract enhances the antioxidant capacity of the fruit and thereby inhibits oxygen-free radicals Treatment of 3 g/l seaweed extract had the best effect among the treatments applied in maintaining firmness, fruit weight loss, TA, antioxidant capacity, total phenol and flavonoids and PAL enzyme activity. All three levels of seaweed extract increased the amount of total phenol, flavonoids and antioxidant capacity all over the storage time, but no significant difference was observed among the treatments levels. Based on the results, the application of 3 g/l seaweed extract effectively increased the antioxidant capacity and PAL enzyme activity during 90 days of storage time. As a result, seaweed extract treatment had positive effects on maintaining the quality and increasing the shelf life of kiwifruit during 90 days of storage.ConclusionSeaweed extract is one of the natural compounds and compatible with human health and nature has medicinal and nutritional value that can increase the shelf life and maintain fruit quality in the postharvest period. In summary, foliar application of seaweed extract has a significant effect on fruit firmness, total soluble solids, total acid, vitamin C, phenol and total flavonoids, total antioxidant activity and the enzyme phenylalanine ammonialyase. The appropriate treatment for kiwifruit cultivar ‘Hayward’ is introduced. Among the applied treatments, 3 g/l of seaweed extract had the best effect on firmness (40.40%), fruit weight loss percentage (41.87%), titratable acid (25.37%), vitamin C (33.26%), antioxidant capacity (26.70%), total phenol (81.17%), total flavonoids (103.67%) and PAL enzyme activity (153.75%) compared to the control in 90 days of storage.
Ebrahim Abedi Gheshlaghi; Vali Rabiei; Malek Ghasemi; Javad Fattahi Moghadam; Farhang Razavi
Abstract
Introduction: It is important to understand the structural events associated with flower morphogenesis in horticultural plants, because it has many aspects of practical horticultural significance. Information about different stages of flower initiation and development is important for better management ...
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Introduction: It is important to understand the structural events associated with flower morphogenesis in horticultural plants, because it has many aspects of practical horticultural significance. Information about different stages of flower initiation and development is important for better management of the vineyardsand fruit set. Knowledge of floral ontogeny in kiwifruit is also important for the establishment of breeding programs and for the understanding of the evolutionary processes involved in the development of the floral organs. The main objective of this study was documentation of the differentiation stages of flower buds for better understanding of morphological and external changes in (Actinidiadeliciosa[A. Chev.] C.F. Liang &A.R. Ferguson var.deliciosa) cvs.Hayward (female) and Tomuri (male).
Materials and Methods: The experiment was carried out over two years in a mature 'Hayward' and ‘Tomuri’ kiwifruit vineyard at the Citrus and Subtropical Research Center of Iran (Ramsar city). Pistillate and staminate flowers development was followed from the stage of undifferentiated primordia, present in the axils of leaf primordia in dormant buds since mid-March to early June 2015 and 2016. Equally buds in diameter and size from sixth to twentieth buds on one-year old cane of Hayward and Tomuri selected at 5 to 7 days intervals. They were sampled and fixed in a solution of formalin, ethanol 70%, glacial acetic acid (2:5:1 FAA) then stored in refrigerator. Fifteen buds of each sample dissected under a Nikon SMZ645 stereo zoom microscope. The very dense pubescence within the buds was removed manually without damaging the axillary flower primordia. The remaining pubescence was removed using dissecting needles. Various stages of flower differentiation were explained with principal growth stage 5 of BBCH scale.
Results and Discussion: The first signs of the flower on Tomuri were observed 2 days before bud swelling stage (01), on the March 12th, about one month before bud break in 2015. While in the Hayward variety the first signs of the flower primordia were observed on the March 21th of 2015 (9 days later). At the beginning of bud swelling (01), flower primordia begin to differentiation and at advanced bud swelling stage (03), bracts and sepals initiated. As development proceeded, different parts of flowers initiated acropetally. Lateral flowers were formed in the bud break (07), before initiation of petals. In advanced budburst stage (09) stamen primordia appear almost immediately after petal initiation, as two whorls in 'Hayward' and as three whorls in the Tomuri cultivar. Stigma initiated in the open cluster stage (10) in Hayward cultivar about 24-25 days after bud swell stage. The process of differentiation of buds and reproductive organs in the second year was the same as the first year with the exception that differentiation began earlier than that in the first year. Climatic conditions were affected flower development and in the second year primordia differentiation began earlier two days in Tomuri and six days in Hayward than those in the first year. The advanced budburst stage (09) in Tomuri 9 days and in the Hayward 10 days was occurred earlier than that in the first year. Unlike other tree fruits, flower induction in the kiwifruit occurred about 6 months before flower initiation. Flower primordia differentiation initiated shortly before bud break stage and approximately two months before full bloom. Flower initiation and differentiation time may be partly estimated with external changes of buds development. According to cultivar, chilling and heat requirements and climatic conditions during the research, flower initiation and differentiation period have fluctuation. A reason for the difference between the development stages and different varieties can be caused by the chilling and heat requirements. The more heat requirement, the longer reproductive meristem differentiation period.
Conclusion: An understanding of the flower initiation and development is very important for the research and management of fruit trees. A knowing of flower initiation and differentiation can be developed corrective vineyard management and practices in crisis period and prepared breeding programs. Tomuri initiated and developed their floral organs earlier than those in Hayward. Different external changes in the bud may be partly used to estimate of flower development status. The results showed that flower initiation and differentiation in buds coincided with the beginning of development and elongation of bud in the early of spring.
Ebrahim Abedi Gheshlaghi; Reza Fifaei; Davoud Javadi Mojaddad
Abstract
'Flying dragon' is one of the citrus rootstocks that are considered to be a promised dwarfing rootstock in the world. This experiment was conducted in the Astara research station for study of qualitative and quantitative characteristics of 4 mandarin cultivars (Unshiu, Clementine, Page, and Yunesi) budded ...
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'Flying dragon' is one of the citrus rootstocks that are considered to be a promised dwarfing rootstock in the world. This experiment was conducted in the Astara research station for study of qualitative and quantitative characteristics of 4 mandarin cultivars (Unshiu, Clementine, Page, and Yunesi) budded on 'Flying dragon'. This experiment was carried out with four cultivars in randomized complete bloke design (RCBD) with three replications. Qualitative and quantitative characteristics of fruits, as well as vegetative traits were recorded and analyzed for 3, 6 and 1 years, respectively. The highest yield was observed on Yunesi cultivar in the final year of experiments and the lowest yield was on Unshiu cultivar in the fifth year. TSS/TA and means of fruit weight were affected by interaction of year and cultivar. The highest means of fruit weight was on Yunesi in the years of 85 and the highest TSS/TA was in years of 88 on Clementine cultivar. The highest alternate bearing index obtained in years of 88 on the Unshiu cultivar and the lowest that was on the Page cultivar. The highest yield efficiency, cumulative yield and plant height were observed on Yunesi cultivar, and the highest width and canopy of tree were on Unshiu cultivar. The lowest yield and tree size were on Page cultivar.
