فهرست مطالب m. pahlavan yali

Induced resistance in plants can be manipulated using the application of elicitors. In this study, the effects of Salicylic Acid (SA), chitosan, γ-Aminobutyric Acid (GABA), Serenad Aso (Bacillus subtilis QST713), and combined application of these elicitors were studied on the resistance of canola to cabbage aphid, Brevicoryne brassicae L. (Hemiptera: Aphididae). The number of B. brassicae attracted to canola plants treated with different inducers was significantly lower compared to the control in the field experiments. The lowest population density of aphid was observed on plants treated with SA+GABA and SA+chitosan. Moreover, the highest amounts of glucosinolates in canola leaves were recorded in SA+GABA treatment. The contents of sugar, lipid, and glycogen of B. brassicae were lowest when fed on the plants treated with SA integrated with GABA or chitosan. Furthermore, the activity of catalase, esterase, peroxidase and glutathione S-transferase enzymes was the lowest in SA+GABA and SA+chitosan. These findings suggest that exogenous application of SA integrated with GABA or chitosan on canola plants are successful in suppressing the B. brassicae population and can be considered in integrated management programs against this and other aphids.

Greenhouse whitefly, Trialeurodes vaporariorum Westwood (Hemiptera: Aleyrodidae), is a serious pest of a wide range of plants, such as common bean, cucumber, tomato, pepper, lettuce, etc, in both field and greenhouse production. It typically feeds on the underside of leaves, sucking phloem sap from the plant, which causes both direct damage, by overall weakening the plant and reducing yield, and indirect damage, by excreting honeydew, on which sooty mold grows, as well as transmission of several plant viruses. The widespread use of insecticides to control T. vaporariorum has resulted in developing resistance to the insecticides and affected human’s health and safety. The utilization of plant extract and elicitors is an environmentally safe method that is used in the control recently. Therefore, alternative control strategies are required to minimize the harmful effects of insecticides. In order to control this pest, environmentally friendly methods, especially of plant origin are recently considered by researchers. For this regard, the effect of some organic compounds including methanolic and n-hexanic extract of walnut’s husk or dill’s seeds and salicylic acid, individually and in combination with spirotetramat on population density of greenhouse whitefly’s nymphs and some secondary compounds of bean plant were investigated.
Seeds of common bean, Phaseolus vulgaris L. (Berloty cultivar) were sown and grown in 15-cm-plastic pots in a greenhouse at 25 ± 3°C, 50 ± 10% RH, and a natural photoperiod. For the experiments, potted bean plants at 6-8 leaf stage, highly infested with T. vaporariorum nymphs, were sprayed with 12 different treatments, including: (1) spirotetramat (SP), (2) methanolic extract of walnut husk (MW), (3) n-hexanic extract of walnut husk (NW), (4) methanolic extract of dill seed (MD), (5) n-hexanic extract of dill seed (ND, (6) salicylic acid (SA), (7) spirotetramat in combination with salicylic acid (SP+SA), (8) spirotetramat in combination with methanolic extract of dill seed (SP+MD), (9) spirotetramat in combination with methanolic extract of walnut husk (SP+MW), (10) spirotetramat in combination with n-hexanic extract of dill seed (SP+ND), (11) spirotetramat in combination with n-hexanic extract of walnut husk (SP+NW), and (12) water as a control (CO). After five days, the population density of T. vaporariorum nymphs on bean plants leaves was recorded. Furthermore, the effects of tested treatments on the total phenol and flavonoid contents of bean plants were evaluated. For this reason, dried leaves (5 g) from each treatment were used for the preparation of extracts. The total phenolic of the extracts were determined using the Folin - Ciocalteu reagent. Sample and standard readings were made using a spectrophotometer (Lambda 45-UV/Visible) at 765 nm against the reagent blank. Furthermore, the aluminum chloride colorimetric method was used for determination of the total flavonoid content of treatments. For total flavonoid determination, quercetin was used to make the standard calibration curve. The absorbance was read using a spectrophotometer (Lambda 45-UV/Visible) in the wavelengths of 415 nm. Data were analyzed by one-way ANOVA using SPSS 23.0 software. Comparison of means for nymph density using SNK (Student-Newman-Keuls) multi-range test and comparison of means for secondary chemical compositions using Tukey's test at probability level five Percentage occurred.
Results showed that the population density of greenhouse whitefly and the secondary metabolites of plant were significantly affected by the tested treatments. The lowest number of whitefly’s nymphs was on spirotetramat and spirotetramat in combination with methanolic extract of dill seed and the highest number was on control. Total phenolic contents ranged from 58.96 to 114.07 mg g-1 dry weight on different treatments, which the highest and lowest amount of it was obtained in spirotetramat in combination with methanolic extract of dill seed and spirotetramat in combination with n-hexanic extract of walnut husk, respectively. The highest amount of total flavonoid content of bean plants was in spirotetramat in combination with salicylic acid. The results of the present study showed that the density of greenhouse whitefly population in spirotetramate treatment was lower than other treatments but there was no significant difference with the combined treatments and methanolic extract of walnut husk. Also, all the treatments compared to the control significantly changed the population density of this pest and increased the amount of total phenolic compound in bean plant. Therefore, these compounds, especially the methanolic extract of walnut husk, can be used in integrated management programs of this pest.
This research could provide valuable information for control of T. vaporariorum in other plants like ornamental plants in the field and greenhouse and thus can be useful for the production of healthy and organic crops. So it can be used in the IPM programs of this pest.

Trustocytrides have received a great deal of attention in recent years for producing a significant amount of omega-3 fatty acids. However, their commercial and sustainable production from microalgae sources faces technical and economic limitations. In this study, the effect of temperature and different carbon and nitrogen sources in YEP calture on the growth and fatty acids profile in a newly isolated strain of Aurantiochytrium sp. SHY has been conducted. Glucose produced more biomass, but galactose was more suitable for lipid formation. Galactose promoted the highest production of fatty acids (36.4%), but the ratio of docosahexaenoic acid to fatty acids was 19.05% which was less than glycerol. With an increased glucose concentration, EPA is considerably higher and DHA is only slightly increased. This is the first study that has been carried out on this new isolate wherein a mixed carbon source was used in the culture media and the results showed the microorganism’s preferences for carbohydrate consumption is in the following pattern: glucose > galactose > fructose> sucrose. The meat extract was the most suitable nitrogen source for biomass development (7 g L-1), but the maximum DHA to fatty acids ratio (25%) was achieved when the microorganism consumed monosodium glutamate as a nitrogen source. The strain produced more biomass at 25°C, and lowering the temperature achieved a higher DHA formation. The results of this study show that if this strain is going to introduce as a good potential candidate for food industries and aquaculture, it needs more study in bioreactor that’s going on.

The cabbage aphid, Brevicorne brassicae L., is an important pest of canola in Iran. In this study, the behavioral response of B. brassicae was evaluated on leaves of five canola cultivars (Zarfam, Parade, Hyola401, Syn-3 and RG4403) at the laboratory condition. Development of rate and fecundity were the lowest on Zarfam and highest on RG4403 cultivars. The intrinsic rate of natural increase (rm), finite rate of increase (λ) and net reproductive rate (R0) were lowest on Zarfam (0.24±0.005 day-1, 1.27±0.013 day-1 and 15.8±1.09 33 female/ female, respectively) and highest on RG4403 (0.34±0.009 day-1, 1.40±0.006 day-1 and 72.4±3.47 female/female, respectively). There was no significant difference in generation time (T) of B. brassicae among the studied canola cultivars. The lowest and highest values of mean relative growth rate (MRGR) were observed on Zarfam (0.197 mg day-1) and RG4403 (0.243 mg day-1), respectively. Xylem feeding by the cabbage aphid on resistant canola cultivars was indicated by red color of honeydew on seedlings treated with safranin. The highest numbers of red honeydew spots were seen on Zarfam and the lowest on RG4403. In conclusion, RG4403 was the most suitable cultivar, and Zarfam was the less suitable cultivar among tested plants for B. brassicae.