Many conifers show particularly strong apical dominance, strongest of all in the family Araucariaceae, showing a single erect central trunk with strongly differentiated horizontal branching. Cuttings of Araucariaceae species taken from a side branch will not develop erect growth. Araucaria heterophylla, South Durras, New South Wales, Australia.

In plant physiology, apical dominance is the phenomenon whereby the main central stem of the plant is dominant over (i.e., grows more strongly than) other side stems; on a branch the main stem of the branch is further dominant over its own side branchlets.

Typically, the end of a shoot contains an apical bud, which is the location where shoot growth occurs. The apical bud produces IAA, an auxin that inhibits growth of the lateral buds further down on the stem. 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. Pruning techniques such as coppicing and pollarding make use of this natural response to damage to direct plant growth and produce a desired shape, size, and/or productivity level for the plant.

Weeping larch showing growth habit is lacking apical dominance.

Occasionally, strong apical dominance is advantageous, as in the "Ballerina" apple trees. These trees are intended to be grown in small gardens, and their strong apical dominance combined with a dwarfing rootstock gives a compact narrow tree with very short fruiting side branches.

See also

• Meristem
• Fruit trees pruning

References

ca:Domin ncia apical da:Apikal dominans de:Apikaldominanz es:Dominancia apical it:Dominanza apicale he: hu:Cs csdominancia nl:Apicale dominantie ja: nn:Apikal dominans pt:Domin ncia apical sk:Apik lna dominancia fi:Apikaalidominanssi ta: uk: