Drought stress is one of the most limiting factors in the production of agricultural products in the world. One of the best and most practical methods to reduce the adverse effects of drought stress on plants is the use of biological stimuli. Seaweed extract is a compound from the group of biostimulants that, unlike chemical fertilizers, does not destroy the environment and can increase the tolerance of plants to environmental stresses. Considering the increase in aridity in Iran and the abundant use of pelargonium graveolens medicinally and ornamentally in green spaces, this experiment was designed to eva‎luate the effect of dry seaweed extract on growth and development indicators and the essential oil of pelargonium graveolens. became. A factorial experiment in a completely random format with 3 irrigation levels of 50% crop capacity (severe stress), 75% crop capacity (mild stress) and 100% crop capacity (control) and 4 levels of seaweed extract foliar application (Acadian sea plant company, containing 3% potassium and 10% organic matter) including 0, 2.5, 5 and 7.5 ml/liter with 3 repetitions was carried out in the research greenhouse of Isfahan University of Technology. The results showed that seaweed extract increased the total chlorophyll concentration and activity of catalase and superoxide dismutase enzymes. Algae extract 7.5 ml per liter increased the length, width and area of the aromatic geranium leaves. This treatment in the conditions of moisture stress of 50% of the agricultural capacity improved the dry weight of shoot, the relative content of leaf water, total chlorophyll, the amount of protein and antioxidant activity compared to the same treatment. Drought stress caused a decrease in the amount of antioxidant activity of the extract. Algae compensated for its reduction. In total, the moisture stress of 50% of the agricultural capacity and algae extract of 5 milliliters per liter increased the quality of aromatic candlestick essential oil, and with the increase in the concentration of algae extract, both the amount of essential oil and the composition of the essential oil increased.

مهدي رحيم ملك , مهديه غلامي

نعمت اله اعتمادي شلمزاري , علي نيك بخت

محمدرضا سبزعليان دستجردي , حميدرضا عشقي زاده