<P> Plant physiology describes apical dominance as the control exerted by the terminal bud (and shoot apex) over the outgrowth of lateral buds . </P> <P> Apical dominance occurs when the shoot apex inhibits the growth of lateral buds so that the plant may grow vertically . It is important for the plant to devote energy to growing upward so that it can get more light to undergo photosynthesis . If the plant utilizes available energy for growing upward, it may be able to outcompete other individuals in the near vicinity . Plants that were capable of outcompeting neighboring plants likely had higher fitness . Apical dominance is therefore most likely adaptive . </P> <P> Typically, the end of a shoot contains an apical bud, which is the location where shoot growth occurs . The apical bud produces an auxin (IAA) that inhibits growth of the lateral buds further down on the stem towards the axillary bud . It was first discovered in 1934 that the plant hormone auxin likely regulates apical dominance . Auxin is predominantly produced in the growing shoot apex and is transported throughout the plant via the phloem and diffuses into lateral buds which prevents elongation . </P> <P> When the apical bud is removed, the lowered IAA concentration allows the lateral buds to grow and produce new shoots, which compete to become the lead growth . </P>

Explain the role of auxins in apical dominance