S. Zare Dehabadi; Z. Asrar
Volume 24, Issue 4 , February 2009, , Pages 530-540
Abstract
The conditions used for spearmints growth in this work have been adequate for testing range of tolerance and adaptation to excess zinc. For studying oxidative changes, antioxidanic responses and metal accumulation in Spearmint (Mentha spicata L.) in reply to zinc, plants remained in a controlled environment ...
Read More
The conditions used for spearmints growth in this work have been adequate for testing range of tolerance and adaptation to excess zinc. For studying oxidative changes, antioxidanic responses and metal accumulation in Spearmint (Mentha spicata L.) in reply to zinc, plants remained in a controlled environment for 12 weeks in nutrient solutions that contained different doses of zinc. This study showed that Zinc as heavy metal induced oxidative stress as evidenced by an increase in lipid peroxidation (malondialdehyde and other aldehydes). Under Zn treatments, phenolic compounds such as flavonoids and anthocyanins were increased significantly compared to control plants. The total protein content in leaves increased significantly by increment concentration of Zn but decreased with higher Zn supply. Lipid peroxidation (MDA) was increased only in the highest concentration of zinc. High levels of Zn decreased the shoot to root translocation of Zn and Fe which caused accumulation of these metals in root. In general, the results of this investigation proved high antioxidanic capacity in spearmint plants.
F. Ghanati; Z. Ahmadi; P. Abdolmaleki
Volume 22, Issue 4 , February 2007, , Pages 315-331
Abstract
The increase of atmospheric pollutants and depletion of ozone, are subsequently the main causes for the increase of ultraviolet radiation on the earth. In the present research the effect of ultraviolet C (100-280 nm) on the content of some of the biochemical compounds and growth parameters of Aloe vera ...
Read More
The increase of atmospheric pollutants and depletion of ozone, are subsequently the main causes for the increase of ultraviolet radiation on the earth. In the present research the effect of ultraviolet C (100-280 nm) on the content of some of the biochemical compounds and growth parameters of Aloe vera L. were examined. According to the results, exposure to ultraviolet C decreased both longitudinal and expansion growth, as well as the size of mesophyll layers of aloe leaves, but increased the thickness of cuticle layer. The histochemical methods also showed that phenolic compounds in the cell walls of those plants which were exposed to ultraviolet irradiation were deposited more esterified to the wall polysaccharides rather than being polymerized compared to those of the non-exposed plants. The content of the ultraviolet-absorbing compounds (i.e., anthocyanins and flavonoids) of UV-exposed plants were also changed. Increase of flavonoids and anthocyanins in these plants, may be related to defensive strategy of these compounds against irradiation.
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 ...
Read More
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.
R. Khavari-nejad; A. Asadi
Abstract
Plants produce a diverse array of secondary metabolites. These compounds may be synthesized during normal growth and development and accumulating only in response to pathogen attack or stress. Interest in these molecules stems from their medicinal properties, antimicrobial activity and their likely role ...
Read More
Plants produce a diverse array of secondary metabolites. These compounds may be synthesized during normal growth and development and accumulating only in response to pathogen attack or stress. Interest in these molecules stems from their medicinal properties, antimicrobial activity and their likely role as determinats of plant disease resistance. Daisy (Bellis perennis L.) accumulates secondary compounds (triterpenoid saponins and anthocyanins) in response to SA and pathogens. The results of the research indicates that the amount of secondary compounds (saponins and anthocyanins) in treated plants with SA were more than in the control plants. The amount of compounds in infected plants and without SA was more than in the control plants. When infected plants were treated with SA, an increase of compounds was shown in plants. The peaks observed in HPLC and their comparision with compounds standard confirms the results mentioned above. It is concluded that SA have significantly reduced disease severity and increase the amount of secondary compounds in infected and non-infected Daisy plants.
