Effects of different fertilizers and the foliar application of L-phenylalanine on mineral contents of hyssop [Hyssopus officinalis L. subsp. angustifolius (Bieb.)]

In order to improve the quantity and quality of medicinal plants, the use of natural substances such as amino acids have increased in recent years, which provide little information on their individual effects, as well as interaction with other fertilizer sources.

To investigate effect of different fertilizers and the foliar application of L-phenylalanine on nutritional elements of hyssop [Hyssopus officinalis L. subsp. angustifolius (Bieb.)], an experiment was done in a randomized complete block design with three replications during two consecutive years of 2016 and 2017 in a field experiment at the experimental field, Shahrekord. The investigated factors were fertilizer treatments including chemical fertilizer (NPK), organic fertilizers (animal and vermicompost) and a bio-fertilizer, mycorrhizal fungus (including Glomus genus) in the main plots and L-phenylalanine (at three levels: 0, 500, and 1000 mg/L) in sub plots.

Results indicated that the application of different fertilizers along L-phenylalanine at two studied concentrations (500 and 1000 mg/L) led to significant increase in the concentration of most nutrient elements including nitrogen (N), phosphorus (P), potassium (K) and micro elemts [Iron (Fe), zinc (Zn), manganese (Mn) and copper (Cu)] in the leaf were compared to the control. Among them, the application of fungal and vermicompost fertilizers, L-phenylalanine × fungal fertilization, and phenylalanine × vermicompost had highest effects on the increase of these traits. In conclusion, the results indicated that the application of organic fertilizers along with L-phenylalanine spraying at 1000 mg/L level has a beneficial role in the improvement of nutritional elements and dry matter yield of H. officinalis L. subsp. angustifolius (Bieb.).