The use of biostimulants is a method of limiting the negative effect of stress on crops. The aim of the study was to determine the influence of amino acids and a combination of Ascophyllum nodosum filtrate and amino acids on the content of macro- and micronutrients in two broccoli cultivars exposed to drought stress. The experiment was conducted in vegetation chambers in two cycles in 2015. The plants were watered with Ascophyllum nodosum filtrate three days before planting and sprayed three times with amino acids two, four and six weeks after planting. The control plants were not treated with biostimulants. The water content in the substrate was determined with moisture sensors 5TE and Em50 data logger (Decagon Devices, Inc., USA). The water capacity of the soil was 40% v/v. During the 12 days of cultivation, drought stress was repeated three times. Each time it lasted until the substrate reached 15% v/v. Next, the plants were watered to 40% v/v and the stress started again. The content of macro- and micronutrients in broccoli leaves was determined when the experiment finished. The level of plant stress caused by the factors under study was determined by measuring chlorophyll fluorescence parameters. The maximum photochemical efficiency of PSII and the quantum yield of electron transport were calculated. The biostimulants significantly affected the content of nitrogen, phosphorus, potassium, magnesium, copper and manganese in broccoli leaves. The content of magnesium and sodium depended on a cultivar. The research revealed a highly significant linear dependence between the content of nitrogen, phosphorus, potassium, magnesium and sodium and the value of quantum yield of electron transport in the plants treated with the biostimulants.

23.1.2018