بررسی اثر سطوح مختلف کود اوره و منابع مختلف کود آهن بر عملکرد کمی و کیفی به‌لیمو (Lippia Citriodora H. B. & K.)

به‏لیمو (lippia citriodora h. b. k.) از گیاهان دارویی ارزشمندی است که اسانس آن در صنایع دارویی، غذایی، آرایشی و بهداشتی کاربرد دارد. این آزمایش به منظور بررسی اثر سطوح مختلف کود اوره و انواع کودهای آهن بر عملکرد کمی و کیفی به‏لیمو در سال 1396 در باغ فتح آباد کرمان اجرا شد. آزمایش به صورت فاکتوریل در قالب طرح بلوک‏های کامل تصادفی در سه تکرار انجام شد. تیمارها شامل کود اوره در چهار سطح صفر (شاهد)، 100، 150 و 200 کیلوگرم در هکتار و منابع مختلف کود آهن شامل عدم استفاده (شاهد)، سولفات آهن 17 درصد به میزان 10 کیلوگرم در هکتار، نانو کلات آهن 9 درصد به میزان 5 کیلوگرم در هکتار و کلات آهن اورتو 4.8 درصد به میزان 10 کیلوگرم در هکتار در نظر گرفته شدند. صفات مورد اندازه‏گیری شامل ارتفاع گیاه، وزن تر و خشک برگ در بوته، تعداد شاخه، میزان کلروفیل و کمیت و کیفیت اسانس بودند. نتایج نشان داد که سطوح مختلف اوره و منابع مختلف آهن بر کلیه صفات اثر معنی‏دار داشت. تیمار 150 کیلوگرم اوره در هکتار بیشترین تاثیر را بر صفات اندازه‏گیری شده نسبت به شاهد داشت. در مجموع استفاده توام 150 کیلوگرم در هکتار اوره به همراه کلات اورتو آهن بالاترین عملکرد کمی و کیفی، محتوای کلروفیل (35 میلی‏گرم بر میلی‏لیتر) و درصد اسانس (1.3 درصد) را ایجاد نمود. همبستگی مثبت و معنی‌داری بین محتوای کلروفیل برگ‌ها با صفات رویشی و اسانس ملاحظه شد. در ارزیابی کیفی اسانس، 20 ترکیب شیمیایی شناسایی شد که دو ترکیب ژرانیال و نرال اجزای غالب بودند که کمترین میزان این ترکیبات در شاهد (33.8 درصد) و بالاترین میزان این ترکیبات در تیمار 150 کیلوگرم کود اوره همراه با کلات آهن اورتو (44.9 درصد) مشاهده گردید.

The Effect of Different Levels of Urea and Iron Fertilizer Resources on Yield and Quality of Lemon Verbena (Lippia citriodora H. B. K.)

Introduction: Lemon verbena (Lippia citriodora H. B. k.) is a valuable medicinal plant because of the essential oils, such as neral and garanial, which are used in the pharmaceutical, food, cosmetic and sanitary industries. In different industries, using essential oil of medicinal plants depends on the chemical composition, which is influenced by environmental factors, harvest time and farming methods.;Materials and Methods: This experiment was conducted to investigate the effect of different levels of urea fertilizer and several iron fertilizers on yield and quality of lemon verbena at Fathabad garden of Kerman in 2017. The plants were planted based on factorial experiment in format of a randomized complete block design with three replications. Different levels of urea fertilizer (0, 100, 150 and 200 kg ha1) and different sources of iron fertilizers included nonuse, iron sulfate, nano iron chelate and orthochelate iron, were considered in four levels. The measured traits included plant height, fresh and dry weight of leaf per plant, number of branch, chlorophyll content and essential oil quantity and quality. Essential oil extraction was carried out using water distillation method using Clevenger apos;s apparatus and identification of essential oil compounds was performed by gas chromatography–mass spectrometry (GC/MAS). The data were subjected to variance analysis using SAS software and means comparison were done with LSD at 5% level.;Results and Discussion: The results showed that different levels of urea and various iron sources had significant effect on all traits. Treatment with 150 kg ha1 urea had the highest effect on measured traits compared to control. Among the types of iron sources, orthochelate iron had highest effect on quantity and quality compared to other iron sources and control. Generally, 150 kg ha1 urea in combination with orthochelate iron produced the highest quantitative and qualitative yield. The same trend was observed in chlorophyll (35 mg/ml) and oil content (1.3%). In this study, a significant positive correlation was observed between chlorophyll content of leaves with vegetative traits and essential oil, which confirmed the positive effect of chlorophyll content on measured traits. Evaluation of quality of the leaves, 20 chemical compositions were detected in essential oils that were more than 85 percent of the total components. The neral and geranial were the predominant compounds in essential oils and the lowest levels of these compounds were observed in control (33.8%) and the highest levels were observed in the combination of 150 kg ha1 urea with nano iron chelate (44.9%). The essential oils are terpenoid compositions that their constructive units need to NADPH and ATP, thus the presence of nitrogen is essential for the formation of these compounds. Moreover, iron acts as a cofactor for NADPH and ATP activity in nitrogen metabolism. Therefore, the increase in nitrogen and iron absorption by the plant has increased the content of essential oil. Due to the fact that geranial and neral are the most important compounds used in the essential oil of lemon verbena in various industries, especially pharmaceutical industry. The results of this experiment can be used to increase the quantity and quality of lemon verbena.;Conclusion: The current study demonstrated that different levels of urea and various iron sources had a significant effects on all traits. Generally, 150 kg ha1 urea in combination with orthochelate iron produced the highest quantitative and qualitative yield. A significant positive correlation was observed between chlorophyll content of leaves with vegetative traits and essential oil. Twenty chemical compositions were detected in essential oils that the neral and geranial were the most predominant compounds.