Volume 0, Issue 0 (ARTICLES IN PRESS 2024)
Abstract
Entomopathogenic fungi, Beauveria bassiana and Metarhizium anisopliae are important and effective biocontrol agents against arthropod pests. Compared to chemical insecticides, insect pests do not easily develop resistance against these fungi. In this study, the mortality and phenol-oxidase activity of the Helicoverpa armigera 3rd instar larvae were evaluated after exposure to the B. bassiana and M. anisopliae. The LC50 values for B. bassiana and M. anisopliae were 0.795 ×106, and 5.972 ×107 spore ml-1, respectively. LC30 and LC10 of either entomopathogenic fungi were injected into body of larves, then, 24 and 48 hours after injection, their hemolymph was extracted. After 24 h the highest and lowest phenol-oxidase activity was observed in LC30 of M. anisopliae, and LC10 of B. bassiana, respectively. After 48 h of infection, phenol-oxidase activity increased in all treatments. At the LC30 of M. anisopliae, the highest phenol-oxidase activity was recorded, and other treatments also showed a significant difference compared to the control. Five types of hemocytes including prohemocytes, plasmatocytes, granulocytes, onocytoids, and spherulocytes were identified in the hemolymph of larvae. The highest total hemocytes count (THC) was recorded in LC30 M. anisopliae at 9 h after initial infection. Our results showed that both fungi have the ability to affect phenol-oxidase enzyme activity. These microbial insecticides exhibited high potential for controlling the pest.
Volume 0, Issue 0 (ARTICLES IN PRESS 2024)
Abstract
Polycyclic aromatic hydrocarbons (PAHs), a class of organic pollutants, have been observed to exert deleterious effects on plant growth and various physiological processes. In this study, the effect of different concentrations of phenanthrene (0, 25, 50, 75, and 100 ppm) on growth parameters, photosynthetic pigments, some antioxidant enzymes, and some biochemical compounds of the maize plant were investigated. The experiments were conducted as pot cultures of plants under controlled conditions using a completely randomized design (CRD) with three replications for each treatment. Increasing phenanthrene concentration reduced all studied growth parameters and significantly increased photosynthetic pigment contents. Phenanthrene led to the increase in catalase, peroxidase, and superoxide dismutase activities in the roots but in shoots, only the peroxidase activity was increased. Moreover, higher phenanthrene concentrations were associated with elevated levels of malondialdehyde and hydrogen peroxide, coupled with a marked reduction in soluble sugar content in both shoot and root tissues (p<0.05). Also, increase in phenanthrene concentration in the shoots decreased the total phenol and flavonoid contents compared to anthocyanin. Phenanthrene treatment led to a significant reduction in the concentrations of lauric acid, meric acid, palmitic acid, and oleic acid in maize shoots. In conclusion, it seems that high concentrations of phenanthrene induce oxidative stress in the maize, and plants improve their enzymatic antioxidant system to moderate the stress condition. In addition, damage of cell membranes by phenanthrene leads to weakening of plants root system as well as disordering in water and nutrient uptake and finally reduction in the plant growth.
Dr Mohammad Ali Motafakkerazad, Dr Ahmad Assadzadeh, Mr. Mahdi Sheykhmaollayi,
Volume 19, Issue 1 (Spring 2019 2019)
Abstract
Income distribution is of crucial importance for policymakers from the social justice viewpoint. In recent years, financial tools and intermediaries have been developed in the global economy. Thus, investigating the impact of financial development on the income inequality has attracted the attention of economic researchers. Financial development affects income distribution through both channels of economic growth (directly) and increasing access to financial services (indirectly). Many studies have been conducted regarding the effects of financial development on income distribution in Iran with different methods and indicators, and even contradictory results. This study analyzes the effect of financial development on income inequality using various indicators and the structural vector auto-regression (SVAR) approach. The findings confirm the direct effect of financial development on income inequality, or the inequality-narrowing hypothesis, though they have no decisive implication on the indirect effects of financial development on income inequality, or the inequality-broadening hypothesis.
