تأثیر محلول‌پاشی اسید آمینه‌های فنیل‌آلانین و تیروزین بر شاخصه‌های رشد، عملکرد و اسانس نعناع دشتی

نوع مقاله : مقاله پژوهشی

نویسندگان

• محمدکاظم صالحی ¹
• محمدتقی عبادی ²

¹ گروه علوم و مهندسی باغبانی، دانشکده کشاورزی، دانشگاه تربیت مدرس تهران

² گروه علوم باغبانی، دانشکده کشاورزی، دانشگاه تربیت مدرس، تهران، ایران

چکیده

کلیدواژه‌ها

• اسانس
• محتوای فنول‌کل
• محرک‌های‌ رشد
• عملکرد

موضوعات

• علوم گیاهان دارویی

عنوان مقاله [English]

Effects of L-Phenylalanine and L-Tyrosine Foliar Application on Growth Characteristics, Yield, and Essential Oil of Spearmint

نویسندگان [English]

• Mohammadkazem Salehi ¹
• Mohammad Taghi Ebadi ²

کلیدواژه‌ها [English]

• Biostimulants
• essential oil
• total phenol content
• yield

Extended Abstract

Introduction

Spearmint (Mentha spicata L.) is a perennial and aromatic herb, known for its sweet, refreshing flavor and aroma. it is widely cultivated and used in various food and pharmaceutical industries. Utilizing growth stimulants on medicinal plants is being assessed as a sustainable agricultural strategy to increase the production of active compounds. These stimulants enhance plant growth and development, potentially leading to higher yields of desired medicinal components. Amino acids, like L-phenylalanine and L-tyrosine, are considered growth stimulants in plants because they play a crucial role in protein synthesis and the production of secondary metabolites, which contribute to plant growth and overall quality. These amino acids are building blocks for proteins. Limonene and carvone are the main components of spearmint essential oil. This research aimed to improve the growth parameters, the total content of phenolic compounds as well as the yield and main components of the essential oil of spearmint through foliar application of L-phenylalanine and L-tyrosine.

Materials and Methods

This study was conducted under two conditions, including greenhouse and farm condition, to investigate the effect of two amino acids, L-phenylalanine and L-tyrosine, at five different concentrations (0, 250, 500, 750 and 1000 ppm) on growth indicators, yield and essential oil of spearmint. Therefore, two separate split plot experiments on the basis of a completely randomized design within greenhouse and a completely randomized block design on farm were carried out with 3 replications at the experimental field of the Faculty of Agriculture, Tarbiat Modares University. Spearmint rhizomes were provided from the Tarbiat Modaares University mint collection in Tehran and cultivated in pots contain soil: manure: sand (7:3:3) and kept in greenhouse. In farm experiment, first cultivation operation was done and soil fertilized using manure. Then plots measuring 2×9 m were created and six spearmint rhizomes were planted in each plot at appropriate intervals. Amino acids were applied three times during the experiments; irrigation was also done similarly for all treatments in each experiment. At the time of flowering, spad index, plant height, diameter of the main stem, number of lateral branches, number of leaves and leaf area were recorded. When 50% of the plants reached to flowering stage, plants were harvested in two cutting stages and dried in shade for further studies. The dry weight of aerial parts and the ratio of leaf to stem weight were calculated. The essential oil of samples was isolated by clevenger apparatus using hydro-distillation method and were analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS) to identify and quantify the components of the essential oil. Methanolic extraction of leaves were prepared, and the Folin-Ciocalteu method was used to determine the total phenolic content.

Results and Discussion

The results showed that both amino acids had significant effects on the growth and biochemical characteristics of the plants. Under greenhouse conditions, L-phenylalanine at 250 ppm in the first cutting, and L-phenylalanine at 1000 ppm in the second cutting exhibited the most significant effects on studied traits. However, in farm conditions, the most significant impact of amino acids on the studied traits was recorded for both L-phenylalanine at 500 ppm and L-tyrosine at 500 ppm in the first cutting, as well as L-phenylalanine at 750 ppm in the second cutting. The highest levels of carvone (72.4%) and limonene (29.3%) were observed in the L-phenylalanine at the concentrations of 1000 and 250 ppm, respectively, in the second cutting under greenhouse conditions. In general, L-phenylalanine applied at a concentration of 1000 ppm in the greenhouse and at 500 ppm on the farm yielded the most favorable outcomes.

Conclusion

Growth stimulants, can be a part of sustainable agricultural practices by enhancing plant growth and resilience without necessarily relying on synthetic inputs like excessive fertilizers. The results of this research indicate that the application of L-phenylalanine 1000 ppm in the greenhouse and L-phenylalanine 500 ppm in the farm as growth stimulants has a beneficial effect on plant growth and yield. Considering the positive impact and alignment with sustainable practices, the use of these growth stimulants can be recommended for wider adoption in agriculture.

Author contributions

1. Mohammad Kazem Salehi: Acquisition of data, Data analysis and interpretation, Drafting the manuscript.
2. Mohammad-Taghi Ebadi: Supervision, Conception and design of study, Data analysis and interpretation, Writing- reviewing and editing.

Data availability statement

The data used to support the findings of this study are available from the corresponding author (MT. Ebadi) upon request.

Acknowledgements

We are thankful to Tarbiat Modares University (TMU) research council for funding this research.

Ethical considerations

This research did not involve any studies on humans or animals. Therefore, no ethical approval or consent was required.

Conflict of interest

The authors declare no conflicts of interest.