Background & Objective: Amino acids have a great impact on plant growth due to having amino compounds and valuable carbon skeleton in their structure. The aim of the present study was to improve the morphological and phytochemical characteristics of purple basil by foliar spraying of L-tyrosine and arginine amino acids.
Materials & Methods: This experiment was carried out in the form of a randomized complete block design with seven treatments and three replications on basil in the research greenhouse of the agricultural faculty of the University of Zanjan. Treatments were at three levels of arginine (2, 4 and 8mM) and L-tyrosine at three levels (2, 4 and 8mM) and control (without treatment) was investigated. In this study some characteristics such as number of leaves, dry and fresh weight of shoot, chlorophyll and carotenoid, phenol and flavonoid, antioxidant and percentage of essential oil were determined.
Results: The obtained results illustrated that application of L-tyrosine enhanced the chlorophyll a (42.5%) and total chlorophyll content (32.3%) and L-tyrosine treatment increased carotenoid (32.8%) content at higher level in comparison with control. High levels of total phenol (45.8%), flavonoids (35.1%), antioxidant capacity (28.5%), number of leaves (33.6%) and percentage of essential oils (62.5%) were observed in L-tyrosine (8mM) treated basil plants. The spraying of L-tyrosine and arginine at 8 mM concentration significantly increased the number of leaves (33.6 and 32.3%), fresh weight of shoot (43.4 and 42.8%) compared to the control treatment.
Conclusion: Spraying arginine and L-tyrosine improved the quality and antioxidant characteristics of plants. In conclusion, application of arginine and L-tyrosine as one of the safe and natural nutrients could increase the morphological and phytochemical characteristics of purple basil medicinal plant.
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