Volume 8, Issue 4 (11-2010)
Abstract
Salvia leriifolia (Lamiaceae) is an endemic plant of Khorasan and Semnan provinces which has antinociceptive, anti-inflammatory, antidiabetic and antioxidant properties. In this research, antibacterial activity of of S. leriifolia leaf was investigated at different growth stages and the best harvesting time was determined. The leaves were harvested at vegetative (mid March), flowering (mid April) and ripening seed stages (late May). Different concentrations of metanolic extract(5,10,15 and 20 g/l) of leaves were applied on five different bacteria(Pseudomonas aeruginosa, Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli and Proteus mirabilis) according to dick diffusion method. Inhibition zones were measured after 24 hours. Inhibitory effect of extracts at different stages were compared together and with certain antibiotics (Penicillin, Ampicilin and Tetracaiclin). Statistical analysis was performed through the JMP software. Maximum antibacterial activity of leaves was coincident with flowering stage. In this stage, antibacterial activity of leaves was significantly higher than the vegetative and ripening seed stage. Inhibitory effect of leaf extract at flowering stage on some bacteria was higher than the antibiotics or similar with them. It seems that flowering stage (mid April) is the best time for obtaining the maximum antioxidant activity of leaf.
G Rabani, R Ezati,
Volume 15, Issue 1 (4-2015)
Abstract
Acid rain, which is a wet form of gaseous air pollutants, is formed when air pollutants such as SO2, NO2, CO2 in atmosphere combine with water vapor of clouds. With the addition of concentration of these pollutants the amount of acid rain is increases. Acid rain that is the mixture of sulphuric acid, nitric acid and carbonic acid lead to change in the soil like the decrease in pH, nutrient liberation, the increase of releasing in toxic metals and the decline in fertility of soil that these cases results negative effects on plants. In present work wheat plants irrigated and leaf spraied with four treatments of acid rain which contain sulphuric acid and nitric acid with pH= 2.5, 3.5, 4.5, 5.6 for a period of 32 days, whereas, control plants irrigated and leaf spraied by normal water at pH= 7.4 . According to the results control plants in whole of growth and physiological indexes were better than treatments of acid rain at pH= 2.5 and 3.5, also plants of acid rain treatment at pH= 4.5 and 5.6, were lower in other factors except photosynthetic rate, pigment content and carbohydrate content than control plants. Also acid rain at pH= 2.5 and 3.5 causes white spot in both surface of leaf and tip and border atrophy.
