Phytoallexins

Abstract Aloe vera gel and extract has many biological and physiological properties and is used in various pharmaceutical, food, cosmetic and health industries. In this study, in order to determine the amounts of total tannin, total phenol, total flavonoid and antioxidant of Aloe vera L. hydroalcoholic extract, an experiment was conducted in a completely randomized design with three replications in 2019.
This research was conducted in a greenhouse located in Dehshak village of Mashhad city, Razavi Khorasan province. A methanolic extract was prepared from the gel of yellow patience leaves. The amount of phenol and flavonoid was measured by spectrometry and the antioxidant activity of the gel extract was measured using DPHH free radical. According to the results obtained from determining the amounts of secondary metabolites and antioxidant activity, the amount of total phenol in the hydroalcoholic extract of yellow patience gel is 90.04 microequivalent grams of gallic acid per milligram dry weight of the gel, the total flavonoid content is 66.25 microequivalent grams. Quercetin per mg dry weight of the gel and total tannin content was 87.43 microequivalent grams of catechin per mg dry weight of the gel. The measurement of antioxidant activity in three methods, DPPH, FRAP and BCB, had a significant positive correlation with total phenol, total flavonoid and total tannin content. The results of this study showed that yellow patience gel has high antioxidant activity and also has a direct relationship with the amount of phenolic and flavonoid compounds.

Abstract Extracts obtained from plants, which are mainly extracted from natural sources and different parts of plants, have been considered as a natural and efficient alternative to replace chemical pesticides. In this study, Eucalyptus camaldolensis and Thyme vulgaris plants were selected as plant sources to extract active and effective compounds from them by using an aqueous solvent. The purpose of this extraction was to investigate the effect of different concentrations of aqueous extract formulation on the mortality rate of 3rd instar larvae of the cotton bollworm (Helicoverpa armigera) in a laboratory environment. The results of this study showed that the use of different concentrations of aqueous extracts of eucalyptus and thyme produced statistically significant differences in the mortality rate of 3rd instar cotton bollworm larvae within 24 hours (p≤0.05). In the study of the lethality of the concentrations of 60%, 70%, 80% and 90% of aqueous extracts of eucalyptus and thyme, the results indicated that the concentrations of 80% and 90% caused the greatest losses to the 3rd larval instar of cotton bollworm H. armigera after 24 They created hours, which were equal to 25.00% and 25.00% for eucalyptus aqueous extract, respectively. While the concentration of 60% and 70% caused the lowest losses (20.00%), and for thyme aqueous extract it was equal to 25.00% and 25.00%, respectively, and the concentration of 60% and 70% caused the lowest losses (20.00%). As a result, aqueous extract formulations of eucalyptus and thyme showed similar toxic effects on cotton bollworm pest.

Abstract In this research we assess the effects of the galbanum, Ferula gummosa essential oil against oviposition deterrence and egg hatching rate of Ephestia kuehniella and its parasitoid, Habrobracon hebetor. For this purpose, essential oil was obtained from resins of F. gummosa, and subjected to hydro distillation using a modified Clevenger-type apparatus. The test was assessed at 27±1°C and 60±5% RH, in dark conditions. In both insects, considerable differences in oviposition detternce and egg hatching rate were noted with different concentrations. The results showed that with the increase in the concentration of essential oil, the oviposition deterrence of adult female insects of E. kuehniella and its parasitoid, H. hebetor, first was increased and then decreased. A decrease in egg hatching rate of the moth and its parasitoid was observed as concentrations of the oil were increased. Data probit analysis showed that LC50 of the one and two days E. kuehniella eggs and H. hebetor eggs that were laid on treated larvae of E. kuehniella were 257.613, 176.172 and 3.787 µL/L air, respectively. Results demonstrated that eggs of H. hebetor are so susceptible to this essential oil. The present study demonstrated that the essential oil of the galbanum has effect on E. kuehniella and its parasitoid. Therefore, after supplementary experiments and due to its high oil yield, the possibility of the application of this essential oil as a potential grain protectant can be provided against E. kuehniella.

Abstract The cabbage aphid was developed quicker and stronger resistance to increased application of insecticide than any other pest. In this research, according to the desired effect and harmless essential oils insecticidal activity of sublethal doses, LC10 and LC20 of plant essential oil of Ferula gommosa was studied on fertility life parameters and nymph production deterrence of B. brassicae aphid. The research was conducted in 25±1ºC, 60±5% RH and 16:8 (L:D) photoperiods in germinator. To study sublethal effects of essential oils, 15 fertilized aphids with same age were treated with sublethal concentrations and then fertility life table parameters were calculated and compared with control treatment. The results of bioassay experiments showed that two plant essential oils affected the cabbage aphid. Value of LC10, LC20 and LC50 for F. gommosa were 0.98, 1.86 and 6.31 μl/L air, respectively. The effect of sublethal doses of essential oil on the fertility life table parameters was significantly different from control. The highest effect on the reproductive and birth rates was recorded for LC20 and LC10 of F. gommosa, respectivily. Also treatment of LC20 and LC10 of F. gommosa was decreased the mean generation time and increased the doubling time, respectively. Regarding the nymph production deterrent, there was not significant difference between tested essential oils. The overall results showed that the Galbanum, Ferula gummosa essential oil has a high potential in controlling the cabbage aphid, B. brassicae especially in sublethal concentrations.

Abstract The use of plant pesticides in pest management seems necessary due to the widespread use of chemical pesticides, which has led to environmental damage. Plant extracts are mainly obtained from natural sources of different parts of plants. Therefore, their use in pest management has been considered as a natural and effective alternative to chemical pesticides. In this research, eucalyptus and thyme plants were selected as plant sources to extract active and effective compounds, and plant extracts were extracted using 70% ethanol solvent, and the mortality rate of 3rd instar larvae of the cotton bollworm, (Helicoverpa armigera) was determined concentrations of ethanol extract formulation was determined in laboratory conditions. The results showed that different concentrations of eucalyptus and thyme ethanol extract formulations have a statistically significant difference in the mortality rate of 3rd instar larvae of the cotton bollworm during 24 hours (p≤0.05). In the study of the lethality of concentrations of 20% and 30% and 40% and 50% of the ethanol extracts of eucalyptus and thyme, the results indicated that the concentrations of 30% and 40% and 50% caused the highest losses to the 3rd instar larvae of the cotton bollworm H. armigera After 24 hours, they created 79.993% and 77.493% and 91.243%, respectively. While 20% concentration caused the lowest losses (57.500%). Therefore, the formulation of ethanol extract of eucalyptus has more toxicity for cotton bollworm pest.

Abstract Medicinal plants are important sources of medicinal compounds that have been used in the treatment of many diseases since ancient times. In order to investigate the effect of salicylic acid on the quantitative and qualitative characteristics of marjoram medicinal plant under salinity stress conditions, a factorial experiment was conducted in the form of a completely randomized design with three replications in pots during the year 2015-2016 in the Agricultural and Natural Resources Research Greenhouse. West Azerbaijan was implemented. The first factor is salinity stress at four levels (0 (distilled water), 50, 75 and 100 mM caused by sodium chloride salt) and the second factor is salicylic acid at four levels (0, 0.5, 1 and 1.5 mM). The studied traits included plant height, thousand seed weight, seed and biological yield, essential oil percentage and yield, proline content, malondialdehyde content and antioxidant enzymes. The results showed that the traits evaluated in the present study were affected by the simple effects of salicylic acid and salinity stress. The research results showed that salinity stress decreased plant height, thousand seed weight, seed and biological yield, proline content, essential oil percentage, essential oil yield and antioxidant enzymes content. Also, the use of salicylic acid improved the mentioned traits. The use of salicylic acid increased the activity of the aforementioned antioxidant enzymes and the accumulation of proline. The use of 1.5 mM salicylic acid can be recommended to improve and increase the morphological and physiological characteristics of marjoram medicinal plant.

Abstract Keluss is a member of the umbelliferous family and a car plant with medicinal properties, which is on the verge of extinction in recent years due to improper exploitation and uprooting and bud picking before seeding. This species grows in cold and mountainous bioclimates and is used in traditional medicine for the treatment of various diseases such as cardiovascular diseases, treatment of gastric and respiratory ulcers, and intestinal inflammation. For this purpose, an experiment was conducted to investigate the characteristics of the biological agent and the active ingredients of Keluss medicinal plant in the greenhouse of Shahid University Medicinal Plants Research Center in 2022. Greenhouse experiment included fertilizer treatments (no fertilizer application, chemical fertilizer with nitrogen source and nitrous biofertilizer) in three replicates in the form of pot culture with cocopeat + percolite + peat moss. According to the results of the present research, growth indicators such as dry weight of shoot, plant height, soluble compounds, secondary metabolites and DPPH level were affected by fertilizer treatment. Nitrozist biofertilizer increases physiological traits such as total phenol (2.55 mg/g FW), flavonoid content in three wavelengths and carbohydrate content (4.4 mg/g FW) and antioxidant capacity (28.63%) became Keluss. The application of nitrogenous biofertilizer and the combination of chemical fertilizer treatment of 80 kg per hectare combined with biofertilizer also had a positive effect on root characteristics, flavonoid content and antioxidant capacity of leaves of Keluss medicinal plant.

Abstract Root-knot nematodes (RKNs) are one of the most important plant parasitic nematodes in the world that damage a wide range of plants. Due to the heavy costs of using nematicides and their adverse environmental effects, today there is an increased desire to find eco-friendly control methods. In the current study, the effect of adding crushed masses of plant organs of thyme (Thymus vulgaris), French marigold (Tagetes patula), fennel (Foeniculum vulgare), balango shirazi (Lallemantia royleana) and chamomile (Matricaria chamomillae) to the soil of seedlings tomatoes infected with the RKN, Meloidogyne javanica were studied under greenhouse. After nematode sampling and propagation, nematode inoculum (10 second instar larvae per gram soil) and plant dry mass (zero, 5, 10, 25 and 50 g/kg of soil) were added to the soil and homogenized. The soil was transferred to pots and then tomato cv. Super Chief seedlings were cultivated. The plants were kept in the greenhouse at a temperature of 27±2 °C and natural light (May and June) for two months. After that, the test was stopped and nematode activity was studied by recording the number of galls and egg masses in each root and the nematode reproduction factor. As results, the residue of the tested plants caused a significant (P≤0.05) decrease in the activity of M. javanica on tomato roots. The highest suppression of the nematode was observed on marigold, fennel, thyme, balango shirazi and chamomile, respectively. As a conclusion, the use of some plant residues improves the soil and reduces the activity of RKNs.