Evaluation of usage and time of glycine amino acid application on growth and vegetative organs yield and antioxidant activity of Hyssop (Hyssopus officinalis L .) under different irrigation conditions

Introduction Hyssop (Hyssopus officinalis L.) belongs to the family of Lamiaceae. woody, perennial, shrubs with short, four-stalks, with a height of 50 to 70 centimeters. Its small and reciprocal leaves, the sharp, perfect, very aromatic, and its beautiful flowers, dark blue to purple, white. This herb has a powerful, cough- Soothing, expectorant effect, more or less diuretic and stomach tonic. Drought stress, while decreasing green growth and yield, causes changes in antioxidant activity in this plant. In nature, different environmental stresses threaten the survival, yield and growth of plants. Drought stress is one of the most important environmental stresses limiting the production of plants around the world, especially in arid and semi-arid regions. Drought stress generally destroys and breaks down chloroplates and decreases chlorophyll content and decreases the amount of enzymes activity in the Calvin cycle during photosynthesis and ultimately reduces the growth and yield of the crop. The accumulation of compatible solutes is one of the effective mechanisms for modulating the stresses of dehydration or salinity. This regulation is performed by the production of more organic materials such as protein, soluble sugars, and amino acids such as glycine, proline, alanine and valine in the air and root organs. Glycine is one of the important amino acids in the environmental stresses and chemical formula is NH2-CH2-COOH. This research were investigate the effects of foliar application of glycine amino acid and its application time on growth and yield and antioxidant compounds of Hyssop under different irrigation conditions. Materials and methods The experiment was conducted as split plot factorial in a randomized complete block design with three replications of Yazd agricultural and natural resources research farm in 2016-2017. Irrigation at 25, 50, 75% of the available soil water from the soil, order to control, medium stress, severe stress as the main factor and foliar application treatments in two levels of distilled water (control) and glycine amino acid (2.5 per thousand) and two levels of foliar application (vegetative and just flowering, flowering) were considered as subplots. The measured traits included plant height, lateral branch number, leaf number, fresh and dry weight yield, total phenolic compounds flavonoid and anthocyanin levels. SAS software was used to analyze the data. Mean comparison was performed by LSD at the probability level of 5%. Results and discussion Different irrigation treatments reduced the number of lateral branches, number of leaf, fresh and dry weight yields, total phenol, but the anthocyanin content increased. No significant differences were observed between foliar application time treatments. Interaction effects showed that the combination of control irrigation and foliar application of glycine increased the height and number of lateral branches. Also this material in combination with irrigation mild and severe stress treatments levels increased leaf number, fresh and dry weight yield of plant compared to control. Conclusion The results of this present study indicated that the external application of glycine amino acid in addition to reducing the damage caused by water stress in the plant, also has increased the plant's ability to improve grow and enhance yield.