Effect of growth regulators on selected morphological features of yellow pine

The aim of study was to compare the effects of two growth regulators on selected mor-phological features of yellow pine. In April 2012, 9 plants of yellow pine Lawson variety were planted to the soil. In April 15, 2013 a research agent in a form of following growth regulators: Asahi SL and Moddus 250-EC was introduced. There were the following experimental objects: C – control (only water spraying), As – Asahi spraying, Md – Moddus spraying. The tested features were: increase in plant height (cm), the increase in needle length (cm) of yellow pine. Measurements of increases in length of needles were made in each case on the same specially marked parts of the plants and performed on 27th of each month from beginning of May to ending of September. Among the used of growth regulators the greatest influence on the height increase of the tested trees as well as on the needle length of yellow pine more affected regulator Moddus. The largest total increase in the needles length of yellow pine was on the object with Modus and Asahi, and on control object it was significantly lower than on objects with growth regulators.