R. Kabiri; H. Farahbakhsh; F. Nasibi
Abstract
This research was aimed to evaluate the effect of drought stress, induced by polyethylene glycol (PEG6000), on physiological and biochemical parameters of black cumin (Nigella sativa L.). The traits were included: shoot dry weight, electrolyte leakage, relative water content, photosynthetic pigments ...
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This research was aimed to evaluate the effect of drought stress, induced by polyethylene glycol (PEG6000), on physiological and biochemical parameters of black cumin (Nigella sativa L.). The traits were included: shoot dry weight, electrolyte leakage, relative water content, photosynthetic pigments (chlorophyll a, b, total chlorophyll and carotenoids), malondialdehyde and other aldehyde's contents, anthocyanines, polyphenol compounds, flavonoids, phenylalanine ammonialayse activity, soluble sugar content and protein. An experiment was conducted as a completely randomized design with three replications under hydroponic culture at research laboratory of Shahid Bahonar University of Kerman in 2011. Treatments were four levels of drought stress (0, -0.2, -0.4 and -0.6 MPa). Results showed that drought stress caused a significant reduction in shoot dry weight, relative water content, photosynthetic pigments, anthocyanines, polyphenol compounds, flavonoids and protein and an increase in electrolyte leakage, malondialdehyde content, phenylalanine ammonialayse activity and soluble sugar. Based on the obtained results, it seems that this plant is sensitive to drought stress, and the application of exogenous protective compounds could increase the antioxidant capacity of plant against stress condition.
T. Heidari; Z. Asrar; F. Nasibi
Abstract
One of the methods employed to enhance plant secondary metabolite production is the use of abiotic elicitors in plants. In this research, the effect of heavy metal nickel as abiotic elicitors was studied on some physiological parameters in Hyoscyamus niger L. to investigate the use of unstressful concentration ...
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One of the methods employed to enhance plant secondary metabolite production is the use of abiotic elicitors in plants. In this research, the effect of heavy metal nickel as abiotic elicitors was studied on some physiological parameters in Hyoscyamus niger L. to investigate the use of unstressful concentration of this metal in order to increase secondary metabolite synthesis in later researches. This research was carried out in the Department of Biology of Shahid Bahonar University of Kerman in a complete randomized design with three treatments and three replicates. The seeds of Hyoscyamus germinated in germinator under gibberellin treatment and then were transfered to the pots of sand and peat. After 40 days of growth, the plants were treated with 50 and 100 µM nickel in hydroponics condition (nickel amounts were added to nutrient solution). According to the obtained results, photosynthetic pigments reduced under Ni treatment while hydrogen peroxide, lipid peroxidation and antioxidant enzymes activity increased. Investigation of Ni stress on main macromolecules such as protein, membrane lipids and chlorophyll showed that the effects of 50 and 100 µM Ni was same, while the PAL activity and polyphenols synthesis were the second responses of plants to stress obserevd in 100 µM concentrations. Therefore, it seems that the higher concentration of Ni (100 µM) was more effective for the increment of secondary metabolite in this plant.
F. Nasibi; Kh. Manuchehri Kalantari
Abstract
Ultraviolet spectrum of sunlight has high energy. It was divided into three bands A, B, and C, due to the wavelength. Plants protected themselves from this kind of radiation, by two mechanisms, enzymatic and non-enzymatic. These mechanisms can be used for medicinal plants. Many of the secondary metabolites ...
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Ultraviolet spectrum of sunlight has high energy. It was divided into three bands A, B, and C, due to the wavelength. Plants protected themselves from this kind of radiation, by two mechanisms, enzymatic and non-enzymatic. These mechanisms can be used for medicinal plants. Many of the secondary metabolites including flavonoids, anthocyanin and alkaloids are medicinally important and they as well have a vital role in scavenging of the free radical created by UV radiation. Therefore, UV radiation seems to be able to increase these compounds in plants. In this research the effect of UV-B and UV-C on the amounts of these compounds (flavonoids, anthocyanin and alkaloids ) in hyoscyamus niger and hyoscyamus muticus was studied. The seeds were collected from their habitat, sown in pots in growth cabinet at 21±1ºC and light period of 16/8 light /dark. After 3 weeks, these plants were treated with UV-B and UV-C for 30 minutes every day, during 2 weeks. After 2 weeks, plant materials were harvested and freezed using liquid nitrogen. The samples were used for determination these parameters. Flavonoids were measured by HPLC method. The amount of flavonoids increased in comparison to the control. Anthocyanins concentration were measured using spectrophotometer. The extinction coefficient was used to calculate the concentration. This compound was shown to increase 35% and 50% in UV-B and UV-C, respectively in comparison to the control. The calculation of reducing sugar showed that these sugars decreased in both species when treated either with UV-B or UV-C.
