Agriculture and horticulture
Babak Bahreininejad; Fatemeh Sefidkon; M.H. Lebaschy; Zahra Jaberalansar
Abstract
Background and objectives: Awareness of changes in medicinal plant yield quantity and quality over time is one of the most important goals in agricultural management. Satureja mutica is one of the valuable medicinal species growing in Iran. This study was conducted to evaluate the effects of different ...
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Background and objectives: Awareness of changes in medicinal plant yield quantity and quality over time is one of the most important goals in agricultural management. Satureja mutica is one of the valuable medicinal species growing in Iran. This study was conducted to evaluate the effects of different planting beds on changes in vegetative characteristics and essential oil components over the years of growth in S. mutica under rainfed conditions.Methodology: The experiment was conducted in the form of split plots in a randomized complete block design for three years (2018-2020) in the rainy conditions of Feridounshahr city, Isfahan province. Planting beds as the main plot included cow manure (30 tons per hectare), wheat straw (10 tons per hectare), and control (without cow manure and wheat straw). After the preparation of the field, the seedlings were planted at the bottom of the wells created at a distance of 50 x 50 cm from each other. During the growing season and at the time of 50% flowering, the studied traits including total plant dry weight, leaf and stem dry weight, plant height, crown diameter per plant, canopy area per plant, and in each square meter of land and the number of stems per plant were measured. For essential oil extraction, the flowering branches of the plants were harvested at the full flowering stage. After drying in the shade, the essential oil was extracted by the water distillation method. After determining the yield of essential oils based on the dry weight of the plant, the essential oils were analyzed and identified by gas chromatography, and gas chromatography was connected to a mass spectrometer in the phytochemistry laboratory of the Research Institute of Forests and Rangelands. Considering that the plant is several years old and measurements are carried out every year on fixed plots, the design analysis was done on divided plots at the time of implementation. The SAS computer program was used to perform statistical calculations, and the LSD test was applied to compare the means. For essential oil extraction, the flowering branch of the plant was harvested at the full flowering stage. After drying in the shade, the essential oil was extracted by the water distillation method. After determining the yield of essential oils based on the dry weight of the plant, the essential oils were analyzed and identified by gas chromatography, and gas chromatography was connected to a mass spectrometer in the phytochemistry laboratory of the Research Institute of Forests and Pastures. The SAS computer program was used to perform statistical calculations, and the LSD test was used to compare the means.Results: The variance analysis of the data showed that the effects of bed, year, and their interaction effects on the measured traits were significant in many cases. Results showed that the highest values of plant height, crown diameter, canopy area, and number of stems per plant in the first year were seen in manure treatment. In the last year, they were in control. The highest rates of total dry weight, leaf dry weight, essential oil yield, and essential oil percentage were observed in control in the last year. These rates were 1427, 891, 42 kg ha-1, and 4.67%, respectively. The main essential oil components are thymol, carvacrol, p-cymene, and gamma-terpinene. These essential oil components are affected by the planting bed and the growth year. So in the case of p-cymene, the highest amount obtained in the first year was in the straw treatment. The highest amounts of gamma-terpinene were observed in all three planting bed treatments in the last year of growth. S. mutica had significant amounts of thymol, and the trend of changes among planting bed treatments and during growing years was very small. The highest amounts of carvacrol were observed in straw treatment and animal manure in the second year of growth. The results of the correlation coefficients showed that the most vital traits affecting essential oil yield were total dry weight, leaf and stem, and essential oil percentage. Thymol and p-cymene were inversely correlated with carvacrol and gamma-terpinene.Conclusion: On the whole, to produce S. mutica under rainfed conditions similar to this study, manure or straw could affect yield and essential oil over the first and second years; however, in the third year, this effect diminished, and control treatment was superior to straw and manure treatments.
B. Bahreininejad; B. Abaszadeh; F. Sefidkon; Z. Jaberalansar
Abstract
Two species of Nepeta assurgens Hausskn. & Bornm. and N. eremokosmos Rech., are endemic medicinal plants to Iran. This study was conducted to investigate the vegetative traits, aerial parts yield, the quantity and quality of essential oil, as well as evaluating the relationships between these traits ...
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Two species of Nepeta assurgens Hausskn. & Bornm. and N. eremokosmos Rech., are endemic medicinal plants to Iran. This study was conducted to investigate the vegetative traits, aerial parts yield, the quantity and quality of essential oil, as well as evaluating the relationships between these traits in mentioned species under field conditions in Isfahan. The experiment was carried out in a randomized complete block design with three replications over 2017 and 2018. Results showed that the fresh and dry weight of aerial parts in N. assurgens (11353 and 2351 kg ha-1, respectively) was remarkably higher than that of N. eremokosmos (2638 and 527 kg ha-1, respectively). The average content and yield of essential oil in N. assurgens and N. eremokosmos was 1.60 and 0.64%, and 20.16 and 2.21 kg ha-1, respectively. Based on qualitative analysis of essential oil, the total amount of nepetalactone isomers (4aα, 7α, 7aα-nepetalactone, 4aα, 7α, 7aβ-nepetalactone, 4aα, 7β, 7aα-nepetalactone) in N. assurgens and N. eremokosmos was 78.6 and 62.8% on average, respectively. Correlation analysis showed that leaf dry weight, total fresh and dry weight, and large diameter of the plant had the highest correlation with essential oil yield. Stepwise regression analysis indicated that essential oil yield changes were mainly explained by leaf dry weight, essential oil content, total fresh weight, the number of stems and the amount of plant crown cover. In general, according to the results, the superiority of the N. assurgens species was significant and could be recommended as a valuable and high potential yielding plant for pharmaceutical purposes.
