جستجوی مقالات مرتبط با کلیدواژه « biotic stress » در نشریات گروه « گیاهپزشکی »

Silicon is the most common soil element which has beneficial effects to enhance the tolerance to biotic and abiotic stresses in plants. The addition of silicon to plant nutrient solution decreases sodium concentration, increases plant growth, has positive effects on plant reproduction, and increases mechanical resistance.  Also, silicon affects absorption and translocation of several macro- as well as micronutrient elements and imposes the formation of precipitates under cuticle reduces plant transpiration, and causes resistance to stresses such as side effects of excessive phosphorus and heavy metals (high concentration of manganese and aluminum) or salinity. Furthermore, silicon salts can significantly reduce the diseases in broad bean by reducing the percentage of root colonization and plant death, as well as decreasing root rot compared to controls. Silicon salts such as sodium and potassium silicate cause significant reduction in growth, asexual organ reproduction, and dry weight of hyphae, and prevent cysts' germination in some plant pathogens such as Phytophthora species. The application of silicon salts before and after inoculation of sterilized soil with Phytophthora pistaciae significantly reduces the disease by reducing the percentage of colonized roots and the broad bean's mortality. In this study, in vivo activities of sodium and potassium silicate in controlling Rhizoctonia solani were evaluated.

Studying the effect of sodium silicate (0.5 mM) and potassium silicate (2 mM) to increase the resistance of broad bean against R. solani a factorial experiment in a completely randomized design with salt treatments before and after inoculation was conducted. The level of catalase, peroxidase, polyphenol oxidase, proline, total protein, and carbohydrates in plants, as well as pH and the electrical conductivity of soil were examined.

The results showed that silicon salts might enhance broad bean resistance to R. solani by increasing the level of catalase, peroxidase, polyphenol oxidase, and total protein and decreasing proline. None of the salts had any effects on the level of the plants' carbohydrate content and pH, and the electrical conductivity of soil. As a result, controlling the pathogen is not directly affected by soil pH.

Due to the results, it can be concluded that the role of silicon salts in promoting broad been tolerance could be due to increasing the activities of the antioxidant enzymes which in turn reduced the oxidative damages of reactive oxygen species produced under disease stress.

Abstract In order to evaluate the effect of Fusarium verticillioides on seed yield, catalase (CAT) activity on polyacrylamide gel and quantum yield of maize line, a factorial experiment based on randomized complete block design with five replications during 2017 growing season at the Payame Noor University, Mamaghan branch was performed. The experimental factors were two maize lines (B73 and MO17) and two levels of F. verticillioides (control and fusarium contamination). The results indicated that Fusarium verticillioides reduced seed yield, but enhanced CAT acivity in two maize lines. Further more, minimum fluorescence (Fo) in MO17 decreased, and increased in B73. Water splitting complex at donor side of PSII (FV/Fo) in B73 was increased, but was decreased in MO17. The level of maximum fluorescence (FM) in both line decreased. The energy necessary for closing reaction centers in PSII (Sm) and number of the QA reduction during fluorescence from Fo until FM (N) in MO17 were increased, but were decreased in B73. The results of this study revealed++ using from the chlorophyll a fluorescence can be a rapid and non-destructive method for evaluation of the maize reactions to injures caused by fusarium fungi infections.

Silicon is the most common element in soil that has beneficial effects in enhancing tolerance to biotic and abiotic stresses in plants. The addition of silicon to plant nutrient solution causes decreasing sodium concentration, increasing plant growth, having positive effects on plant reproduction and increasing mechanical resistance. Silicon also affects absorption and translocation of several macro- as well as micronutrient elements and imposes the formation of precipitates under the cuticle, reduces plant transpiration and causes resistance to stresses such as side effects of excessive phosphorus and heavy metals (high concentration of manganese and aluminium) or salinity. Silicon salts such as sodium and potassium silicate causes significant reduction in growth, asexual organ reproduction and dry weight of hyphae, and also prevent the germination of cysts in some plant pathogens such as Phytophthora species. Application of silicon salts before and after inoculation of sterilized soil with Phytophthora pistaciae significantly reduces the disease by reducing the percentage of colonized roots and the mortality of the broad bean. In this study the in vivo activities of sodium and potassium silicate in controlling P. pistaciae and Rhizoctonia solani as a control were evaluated.
Material and To study the effect of sodium silicate (0.25, 0.5 and 0.7 mM) and potassium silicate (1, 2 and 4 mM) to increase the resistance of broad bean as a test plant against P. pistaciae and R. solani a factorial experiment in a completely randomized design with salt treatments before and after inoculation was conducted. In the case of R. solani as a control only 5.0 mM of sodium silicate and 2 mM of potassium silicate were applied. The level of catalase, peroxidase, polyphenol oxidase, proline, total protein and carbohydrates in plants as well as pH and the electrical conductivity of soil were examined.
The results showed that silicon salts may enhance broad bean resistance to P. pistaciae and R. solani by increasing the level of catalase, peroxidase, polyphenol oxidase and total protein and decreasing proline. None of the salts had any effects on the level of carbohydrate content of the plants and pH and the electrical conductivity of soil.
According to the results, it can be concluded that the role of silicon salts in promoting broad been tolerance could be due to increasing the activities of the antioxidant enzymes which in turn reduced the oxidative damages of reactive oxygen species produced under disease stress.