Effect of Foliar Application of Anthracene and Pyrene (pah) on Yields and Chemical Composition of Butterhead Lettuce (lactuca Sativa L.) Grown under Varied Abundance of Substrate in Nutrients

The purpose of this study has been to evaluate the effect of foliar application of PAH organic chemical compounds (anthracene, pyrene) on yield, chemical composition and uptake of nutrients by cv. Vilmorin butterhead lettuce (Lactuca sativa L.). Lettuce was grown under minimum and three-fold higher abundance of substrate in nutrients, as determined according to threshold amounts. A pot trial was established in four replicates and performed twice, in the spring of 2008 and 2009, in a greenhouse at the University of Warmia and Mazury in Olsztyn. Lettuce seedlings were planted in pots containing 10 dm3 of mineral substrate. Fertilization (N, P, K, Mg, Na and Cl) was carried out prior to the planting of lettuce. Under the minimum nutrient abundance of the substrate, all the dose of nitrogen was supplied as a pre-sowing treatment, whereas when the abundance in nutrients was raised three-fold, the nitrogen dose was divided (2/3 pre-sowing and 1/3 10 days after planting). Contamination of lettuce plants with anthracene (ANT) or pyrene (PYR) and their mixture started 10 days after planting lettuce. Foliar application of either of the PAHs continued for 25 days until the vegetative growth of lettuce terminated. Determination of the concentration of macronutrients (N, P, K, Mg, Ca and Na) was performed using standard methods on the mineralised (H2SO4+H2O2), previously dried at 60oC lettuce plant material. The determinations were completed by referring to certified material (CTA-VTL-2). The amount of fresh mass of butterhead lettuce depended primarily on the abundance of the substrate in nutrients. The three-fold increase in the substrate’s abundance in N, P, K,