Evaluation of Effect of Foliar Application of Various Amino acids on the Bochemical Responses of Physalis alkekengi L.

Biostimulants originate from natural and biological sources and in addition to improving plant growth and soil yield, they can protect plants from environmental stresses and stimulate the synthesis of secondary metabolites involved in plant defense mechanism. In this study, to study the effect of foliar application of various amino acids on the biochemical responses of Physalis alkekengi L. an experiment in the form of randomized complete block design with 3 replications in the farm of research Institute of Medicinal Plants of jahad University in Karaj was conducted in the cropping year of 2018-19.Treatments at five levels of amino acid foliar application including {control (A0), tryptophan (1 mg/L) (A1), glycine (1 mg/L) (A2), tyrosine (1 mg/L) (A3) and arginine (1 mg/L) (A4) were administered. Measured variables included: carotenoids, anthocyanins, proline, phenol, beta-carotene, lycopene, ascorbic acid, and alkaloids. The dimensions of the plots were 3×3 m, the distance between each plot was considered to be one meter. Planting operations were done manually in May 2017. The distance between the plants on the culture lines was 25 cm and the distance between the culture lines was 60 cm. Foliar spraying on plants began before flowering. At the time of sampling, three replicates were taken from each treatment and three samples were taken from each replication. Chlorophyll and carotenoids by Lichtenthaler method, anthocyanin by Mita method, proline by Bates method, phenol by Meda method, beta-carotene by Amarowicz method, lycopene by Montesano method, ascorbic acid by titration method, and alkaloid by Iranian Herbal Pharmacopeia method, were measured. The results showed that foliar application of amino acids had a significant effect (p ≤ 0.01) on all evaluated traits and the highest amounts of carotenoids (12.83 mg/gfw), beta-carotene (0.035 mg/gfw), and lycopene (0.017 mg/gfw) from arginine foliar application, highest ascorbic acid (24.2 mg/gfw) and alkaloids (42.25%) from tryptophan foliar application, highest proline (1.4 mg/gfw) Glycine and the highest levels of anthocyanin (12.25 mg/gdw) and phenol (32.44 mg/gfw) were obtained from the control treatment (no foliar application). In general, the results showed that foliar application of amino acids as a biological stimulant had a positive effect on improving the quality characteristics of the Physalis alkekengi L and increased the production of biochemical compounds of the plant.