Azadeh Saffar Yazdi; Ali Ganjeali; Reza Farhoosh; Monireh Cheniany
Abstract
Introduction: Purslane (P. oleracea) is considered as valuable plant due to its high antioxidant compounds and important fatty acids such as omega-3 and 6. Phenolic and flavonoid compounds are one of the most important constituents in the purslane. Phenolics are a large group of natural plant compounds ...
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Introduction: Purslane (P. oleracea) is considered as valuable plant due to its high antioxidant compounds and important fatty acids such as omega-3 and 6. Phenolic and flavonoid compounds are one of the most important constituents in the purslane. Phenolics are a large group of natural plant compounds with antioxidant and Anti-inflammatory properties. Flavonoids, as a subset of phenolic compounds, have a wide range of effects on plants, including antioxidant activity and improve resistance to environmental stresses. Callus culture is one of the important strategies for the production secondary metabolites, which are difficult to produce chemically. Plant growth regulators including auxins and cytokinins play a crucial role in the stages of plant growth. Various combinations of these two hormones are used to make the desired changes in the cultures. Studies suggest that the accumulation of secondary metabolites can be increased by the application of different elicitors in medium. Researchers reported an increase in the content of secondary metabolites such as phenol and flavonoid compounds in calli treated with elicitors such as yeast extract. The purpose of this study was to determine the best explant, medium and hormonal treatment for calli induction of purslane. The effect of different levels of yeast extract on total phenol and flavonoid content and antioxidant capacity of purslane calluses was also investigated.
Materials and Methods: Seeds of purslane plant were cultivated in a solid 1/2MS medium for the preparation of sterile seedlings. The explants from sterile seedlings including to leaves, 1 cm stem specimens and terminal buds, were placed on MS and 1/2MS medium containing 0, 0.1, 0.3, and 0.5 mg L-1 BAP and NAA. After five months, calluses were evaluated for callogenesis and some morphological traits such as color, texture, and size, fresh and dry weight. This experiment was conducted based on completely randomized design with three replications. In the second experiment, the calluses obtained from the previous stage were transferred to MS medium with selected hormone treatment of the first experiment (0.5 mg L-1 NAA and BAP) and different levels of yeast extract (0, 125, 250, and 500 mg L-1). Total phenol and flavonoid contents of the calluses were determined by Folin-Ciocalteau and aluminum chloride methods, respectively. Furthermore, Ferric reducing antioxidant power (FRAP) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays were used to determine the antioxidant activities.
Results and Discussion: The results showed that 1/2MS medium was suitable for sterile seedling production from purslane seeds. Based on the present study, only stem explants in a medium containing BAP and NAA, produced durable calluses. The color of the resulting calluses were green and had a constant and firm texture. The highest callus percentage (90.46%), the size (21.6 mm), and fresh (1826.5 mg) and dry weight (75.33 mg) of calluses belong to MS medium containing 0.5 mg L-1 BAP and NAA. Results of the second experiment showed positive and significant effects of yeast extract on the total phenol, flavonoid contents and antioxidant activities. The highest content of total phenol (664.12 mg GAE 100g-1 DW), flavonoid (42.25 mg QE 100g-1 DW) and FRAP data (787 µmol Fe g-1 DW) were obtained from the calli treated with 500 mg l-1 yeast extract. The maximum DPPH IC50 (2.45 mg ml-1) was also observed in control. The formation of callus associated with plant species, hormonal composition, the stage of development, and the type of explants. Auxin and cytokinin as plant growth regulators are key factors for controlling cell division in tissue culture. In most studies, callus formation in purslane plant were induced in medium containing auxin and cytokinin. The presence of green calluses derived from purslane explants can be due to the formation of chloroplastids in the cells of the callus tissue that rapidly produce chloroplasts under light conditions. In the second experiment, increased phenolic and flavonoid compounds with yeast extract treatment probably resulted in increased antioxidant activity.
Conclusion: In the present study, 1/2MS medium is suitable for the production of sterile seedlings from purslane seeds. MS medium containing 0.5 mg l-1 BAP and NAA is the best treatment for calli induction from stem specimens. The concentration of 500 mg L-1 of yeast extract is introduced as the most effective concentration for increasing the phenolic and flavonoid content and antioxidant activity in the purslane calluses.
Zohreh Chenarani; Farhad Shokouhifar; Mojtaba Mamarabadi
Abstract
Introduction: Iran is the third producer of Melon (Cucumismelo L.) after China and Turkey in the World.Melon is one of the main crops in Khorasan province in the term of cultivation area. The cultivar of Khatooni, among many varieties of melon, can be considered as a breeding cultivar because of its ...
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Introduction: Iran is the third producer of Melon (Cucumismelo L.) after China and Turkey in the World.Melon is one of the main crops in Khorasan province in the term of cultivation area. The cultivar of Khatooni, among many varieties of melon, can be considered as a breeding cultivar because of its great qualitative traits including sweetness and flavor. This cultivar is also economically important and has many attractions for export. However, this cultivar is susceptible to some of plant diseases caused by different bacterial, viral and fungal pathogens which among them vascular wilt caused by Fusariumoxysporum f. sp. melonis (Leach &Currenu) Snyder & Hansen (FOM) is one of the most destructive soil-borne diseases in melon in Iran particularly in temperate and cold regions. The control of melon diseases has depended increasingly on the extensive use of toxic chemicals (pesticides). Many of these chemicals have been shown to be toxic to non-target microorganisms and animals and may be toxic to humans. Another problem with using chemicals to control plant pathogens is that a pathogen may become resistant to the chemicals.
The most promising control approaches are included conventional breeding and genetic engineering of disease-resistant plants. However, the conventional breeding method of melon is very complicated therefore; genetic engineering could be an effective and quick tool for producing new cultivars. In vitro direct regeneration is one of the most crucial step in gene transferring programs (20). In the present study, the effects of explant type and medium were considered in order to optimize the regeneration condition for melon (cv. Khatooni).
Material and Methods: The Khatoonicv.was provided by the Seed Bank of Plant Sciences Research Center from Ferdowsi University of Mashhad. The seeds were disinfected by NaClO in 1 % concentration, washed three times by distilled water and cultivated on MS medium (Murashigo and Skoog) for germination. The explant types were; lateral buds of cotyledon and the true leaves and hypocotyls. The selected media were: M1(0.1 mg.l-1 BAP (6-Benzyl amino purine)), M2 (0.25 mg.l-1 BAP), M3 (0.5 mg.l-1 BAP), M4 (0.75 mg.l-1 BAP),M5 (1 mg.l-1 BAP)and M6(including 0.5 mg.l-1 BAP and 0.01 mg.l-1 NAA (1-Naphthalene acetic acid))The experiment was repeated three times. The experimental –was conducted factorial based on completely randomized design and statistical analysis was performed using the SAS and JMP software. The corresponded graphs were drawn by Microsoft excel 2007.
Results and Discussion: The greatest amount of shoot regeneration in cotyledons was observed in M5 with 1 mg.l-1 BAP while minimum shoot regeneration was observed in M1with 0.1 mg.l-1 BAP. Cotyledon leaves showed the best regeneration efficiency among the other evaluated explants as it has also been reported by many other researchers (12, 8, 20, 21, and 2). The observations showed that in all BAP concentration, hypocotyls only formed callus tissue and did not produce any stem. In all three explants (true leaves, cotyledon and hypocotyls) rooting was observed in a treatment combination including 0.5 mg.l-1BAP and 0.01 mg.l-1 NAA 20 days after cultivation while no stem was formed at the same time. In three weeks after exposure , a weak root system was formed on the rooting mediumin without hormonetreatment . In MS medium enriched with 0.01 and 0.05 mg.l-1 NAA an appropriate root system was formed after 8 to 10 days. The medium containing 0.01mg.l-1 NAA was more appropriate for root regeneration (rooting).
Conclusion: Many studies have been shown that, the manipulation of different phytohormones ratio such as auxin and cytokinin in cultural medium is a suitable strategy to manage differentiation and organogenesis programs in plant (9). In the present study, the effects of explant type and medium were investigated in order to optimize the regeneration condition for melon (cv. Khatooni). As a result, in all BAP concentration, hypocotyls only formed callus tissue and did not produce any stem. However, by increasing of BAP hormone concentration in the cultivated media, shoot regeneration will also increase. The result of our study showed that, cotyledon leaves were more effective on shoot regeneration compared to the true leaves and hypocotyls as it has also been reported by other researchers.
Somayeh Hajian; Sadollah Alizadeh Ajirlo; Fariborz Zare Nahandi
Abstract
Micropropagation is a proper approach to rapid and large-scale propagation of rootstocks and rose cultivars for huge demand of flower market. Proliferation rate of shoot is decreased drastically following several subcultures. Growth regulators have remarkable effects on the key phase of proliferation ...
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Micropropagation is a proper approach to rapid and large-scale propagation of rootstocks and rose cultivars for huge demand of flower market. Proliferation rate of shoot is decreased drastically following several subcultures. Growth regulators have remarkable effects on the key phase of proliferation in micropropagation of this popular crop. In this research the effects of BAP and antiauxin of TIBA on quality and quantity of developed shoots in Rosa hybrida cv. Full House were studied. BAP and TIBA were applied at three concentrations of 0, 2.2 and 8.8 µmol in proliferation phase of micropropagation. The experiment was conducted based on factorial and completely randomized design with four replications. After two months, the percentage of proliferated explants, survived main and lateral shoot number, length of the main and lateral shoots, number of green leaves on the shoots, the average number of shoots with chlorotic and necrotic leaves, the average axillary shoot base diameter, fresh weight of shoots and number of shoots with necrotic tip were recorded. Analysis of variance indicated that BAP was ineffective on the number of the main shoot green leaves and decreasing number of shoots with necrotic tip, but enhanced other traits. The concentration of 8.8 µmol of BAP had greater effect than 2.2 µmol of this growth regulator on mentioned traits. The higher concentration of TIBA resulted to more shoot with necrotic tip. This antiauxin had anegative impact on shoot fresh weight, but the other parameters were not significantly affected.
