Changes in the content of indole-3-acetic acid in the needles of dwarf pine in the course of year

Abstract

The changes in the content of indole-3-acetic acid (IAA) were investigated in the youngest needles of Pinus mugo in the course of year. In newly formed needles, the content of LAA increased, starting from July and reaching its maximum in August to October. The IAA content decreased with a decline in the intensity of apical dominance during dormancy but no changes were observed in budbreak (May and June).