بررسی فاکتورهای محیطی اثرگذار بر عملکرد کمی و کیفی گیاه دارویی چای کوهی (Stachys lavandulifolia Vahl.) در دو دامنه شمالی و جنوبی رویشگاه مرتعی گردنه‌سر سوادکوه

Introduction
Rangeland ecosystems provide diverse services to human societies and have the highest income and profit when they are planned and managed for several types of appropriate exploitation (multipurpose use). rangelands, in addition to their role as conservation value, resort, fodder production, environment, genetic resource, etc., have a special place in terms of production of medicinal and industrial plants. These plants have a special value and are exploited directly (main products) or indirectly (by-products). For the comprehensive and correct study and management of any phenomenon, we must have a complete knowledge of its components and a correct understanding of their relationships with each other. The ecosystem and especially the grassland ecosystems are not exempted from this rule. The growth and performance of plants in pasture ecosystems are influenced by various factors such as species, regional climate, soil environment, altitude above sea level, and geographical location. These factors also affect the quantity and quality of plant products. Considering the influence of climate and soil parameters on the quantity and quality of medicinal plant essential oil, in this research, an attempt has been made to investigate the effect of environmental factors on the quantity and quality of essential oil of Stachys lavandulifolia species in two directions, north and south, in the Gardane-Sar Swadkoh pasture area.





Methodology
Area of study
Gardnesar rangeland habitat located in Sawadkuh city is one of Mazandaran province apart from summer rangeland and is located in geographical coordinates 66◦26´31⸗ to 65◦91´32⸗ east longitude and 39◦95´74⸗
to 39◦94´47⸗ north latitude. According to the data received from the closest meteorological station to the region (Alasht), the total annual precipitation is 377.89 mm and the average annual temperature is around 12.35 degrees Celsius.
Plant and soil sampling
In order to quantitatively and qualitatively evaluate the desired plant in the region, the aerial organs of the adult plant were collected in full flowering season. According to the patchy distribution of the plant in the field, random sampling was done in three selected spots with three repetitions in the north and south directions in the region. Also, to determine soil characteristics, soil samples were taken from the depth of 0 to 30 cm at the base of the plant. Finally, all the plant and soil samples were transferred to the medicinal plant laboratory and the soil science laboratory of Sari University of Agricultural Sciences and Natural Resources to perform the desired tests. The physical and chemical properties of soil were measured based on existing recipes.
Extraction and decomposition of essential oil
After cleaning, the plant samples were dried in the open air in the shade environment. 100 grams of each dried sample was extracted by the clevenger Apparatusin in the central laboratory of Sari University of Agricultural Sciences and Natural Resources by distillation with water for 3 hours. Then it was dehydrated by sodium sulfate anhydride and it was stored in a glass container with a lid in the refrigerator at a temperature of 4 degrees Celsius until injection into the chromatography devices. The resulting essential oil was obtained by injecting into a gas chromatograph connected to a mass spectrometer (GC/MS).Also, the percentage of essential compounds of each compound was calculated. In this research, the most important compounds in the essential oil were reported with a probability of more than 95%.
Statistical Analysis
In order to analyze the quantitative and qualitative data of soil and essential oil, the normality of the data was first checked with the Kolmograph-Smirnov test. Then the comparison of plant chemical compounds and soil quality indicators in the two northern and southern slopes was done using the independent T-student test by Spss version 22 software. Finally, in order to analyze the relationship between plant chemical composition data, soil quality indicators and climate data, principal component analysis (PCA) method was used in PC ord5 software.
Conclution
The result of measuring the yield of essential oil in Gardne Sar rangeland showed that the southern slope had a higher percentage of efficiency in the amount of essential oil than the northern slope. The data obtained from the determination of essential oil compounds indicate that a total of 35 important compounds were found with a probability of more than 95% in the essential oil obtained from plant samples in two domains. among the extracted compounds, compounds of Caryophyllene, α-Pinene, β-Pinene, Myrcene, Linalool, α.-Terpineol, Cyclohexasiloxane, dodecamethyl, Stigmasterol Limonene, Fenchene, α-phellandrene, 7-(1-methyl-ethyl) azulene , Cyclofenchene, Terpinene -4-acetate, p-cymene, Bicyclo, 2-isopropyl, Cis-farnesol, β,-Bisabolene, cis-sabinene hydrate, 1-8-Cineole and Camphene showed a significant difference at the level of one percent in two domains They showed themselves.
On the other hand, Spathulenol (CAS), β phellandrene, Phytol and bicycle germacrene compounds had a significant difference at the 5% level. While the compounds α.-Copaene, α-Thujene, Germacrene D, Comphene, Cyclohexanol, 5-methyl-2-(1-meth..., γ-cadinene, Hexadecanoic acid, Sabinene, beta.-Myrcene and Heptacosane with differences in The average value did not show a significant difference.The measurement of the physical characteristics of the soil in the region showed that the northern slope and the southern slope are not the same in terms of soil texture, so the texture type in the northern slope is loamy and in the southern slope sandy-loamy, and the two slopes are significantly different in terms of the amount of sand and clay. (p≤0.01). Also, the northern slope showed a higher humidity percentage than the southern slope (p≤0.05). This is while the factors of silt, bulk density and soil stability index have not shown significant differences despite the difference in the average value.
The examination of soil chemical factors in the northern and southern slopes indicates that the amount of phosphorus, magnesium, sodium and lime showed a significant difference at the level of 1% and organic matter and nitrogen showed a significant difference at the level of 5%. While soil acidity, electrical conductivity, potassium, and calcium had no significant difference. In general, the results of the analysis of the main components in relation to environmental factors and essential oil compounds showed that the northern and southern ranges are completely different in terms of the measured factors and are placed in two completely separate groups. So that the aforementioned factors justify 82.24% of the total variance changes. Meanwhile, the northern range with the factors of organic matter, rainfall, electrical conductivity, acidity, soil moisture, sodium, silt and compounds α-Pinene, α-Thujene, β-Pinene, Cyclohexanol, 5-methyl., bicycle germacrene, Hexadecanoic acid, Cis-farnesol, cis-sabinene hydrate and the southern domain have established more relationships with nitrogen variables, apparent specific gravity, calcium and compounds α-Copaene, Phytol, Comphene, γ-cadinene, 7-(1-methyl-ethyl) azulene, bicycle germacrene, Heptacosane. In general, according to the obtained data, it can be concluded that the mountain tea plant has a suitable habitat for production in areas with loam texture and suitable rainfall along with soils rich in nutrients. Also, the results obtained from this research compared to the results of other researchers indicate that the quantitative and qualitative performance of the essential oil of Stachys lavandulifolia can be different in different regions.