ABSTRACT
Background: According to the importance of Stevia rebaudiana that it's sweetener steviol glycosides, has been introduced in recent year as a natural alternative for saccharose, the evaluation of bio-fertilizers effects on growth and development of stevia is necessary
Objective: In this research the effect of vermicompost and mycorrhiza on growth traits and steviosid [ST] content in Stevia rebaudiana was studied
Methods: This research was conducted in faculty of agriculture of Tarbiat Modarres University, Tehran, Iran, through a factorial experiment based on randomized complete block design with 12 treatments and 3 replications. The first factor was different levels of vermicompost [0, 10% and 20%] in basal medium including garden soil + 15% by weight Cow manure and also garden soil alone as a control treatment. Second factor was mycorrhiza fungi including inoculation Glomus mosseae and Piriformospora indica and treatment of non-inoculated plants.
Results: The bio-fertilizers had significant effect [P and le;0.01] on the studied parameters. The maximum amount of growth parameters [chlorophyll content, and fresh and dry weight of aerial parts and root] was obtained treatment of 20% of vermicompost and Glomus mosseae inoculation. The highest content of steviosid was obtained in end of vegetative growth stage and control treatment
Conclusion: Application of vermicompost significantly improved the chlorophyll content and growth traits and also the highest their amounts were obtained in combination treatment of vermicompost and mycorrhizal inoculation
ABSTRACT
Thymus daenensis is on e of the endemic aromatic species in Iran that its essential oil is used in food and pharmaceutical industries. In this study, the effects of plant growth stages and distillation methods on essential oil content and thymol percentage of this species were evaluated. The aerial parts of Th. daenensis were collected in three stages of plant growth from Tehran province of Iran. The plant materials were dried in shade and their essential oils were isolated by hydro-distillation in three replications. In addition, the essential oils of plant materials at full flowering stage were obtained by hydro-distillation, water and steam distillation and steam distillation. The essential oils were analyzed by capillary GC and GC/MS. The result showed that the different plant growth stages and distillation methods had significant effect on essential oil content. The highest essential oil content was obtained at full flowering stage [2.28% w/w]. Among distillation methods, the highest essential oil content was obtained by hydro-distillation [2.27%] that was significant difference with other distillation method. There was no significant difference between essential oil composition at different plant growth stages. Also, thymol, p-cymene and y-terpinene were the main components. The highest percentage of thymol was obtained by hydro-distillation. Generally, it can be concluded that harvesting of Th. daenensis at full flowering stage and extraction of its essential oil by hydro-distillation were more suitable for obtaining the higher oil content and thymol percentage
ABSTRACT
Taxol is used to treatment of variety cancers including ovarian, breast, lung, head and neck carcinomas and the AIDS-related Karposi's carcinoma, and was originally obtained from bark of taxus brevifolia. However the amount of extracted taxol from taxus is extremely low and cannot be considered as a suitable commercial source and it has led to studies for finding new sources of Taxol. In 1998, Angela Hoffman and her team reported that hazel could be as a taxol-producing species and it has been confirmed by recent studies. On the other hand, the genes and enzymes involved in taxol biosynthesis pathway in taxus sp. have been identified and characterized but because of very slow growth and difficult somatic embryogenesis, manipulation of taxus is restricted. Instead, hazel with widely contribution in the world, easy invitro culture and characterization of some genes involved in the pathways of MVA and DXP [such as HMGR, IPI and GGPP], makes possibility of manipulation of taxol biosynthesis pathway. In this paper we reviewed a summary of genetic and biotechnology studies on hazel
ABSTRACT
The study of allelopathic properties of plants is one of up-to-date biological and ecological methods, which can lead to discover the bio-herbicides and growth inhibitors. In order to study the allelopathic effects of harmal [Peganum harmala L] on seed germination and seedling growth on purslan [Portulaca oleracea L.] and black weed [Chenopodium album L.], these experiments were conducted. The aqueous extracts of harmal different organs including capsule, leaf, stem and root were applied at five concentration levels [0 as control, 1, 5, 10 and 15%] through a factorial experiment based on a completely randomized design with three replications. The results showed that different organ extracts had different negative effects on seed germination and seedling growth of the two species in such a way that capsules extracts had the highest inhibitory effect. With increasing extract concentrations of harmal, the seed germination and seedling growth of the two species was reduced significantly. The minimum amount of seed germination and growth of the seedlings were observed at 15% extracts concentration of capsules. Also, purslan seedlings appeared to be more sensitive to harmal extracts than black weed seedlings. The aqueous extracts of harmal different organs had inhibitory effects on seed germination and seedlings growth of purslan and black weed. Also, the highest inhibitory effects were related to capsule extracts