The Effect of Naphthaleneacetic Acid on the Epitrophical Growth in Horizontally Positioned Stem of Boehmeria.

The effect of naphthaleneacetic acid (NAA) on the growth in thickness in horizontally displaced Boehmeria stem was studied. NAA inhibits the development of all sorts of tissues on the applied side, irrespective of whether the treatment is made along the upper or along the lower side. Thus, the developmental relations between, both upper and lower sides in the mere horizontal stem are consistent with those in the horizontal one treated with NAA on its lower side, and are contrary to those treated with NAA on its upper. These evidences suggest that epitrophical growth, especially the development of reaction wood, which is normally occurred on the upper side of the mere horizontal stem, is brought about as a response to reduced level of auxin concentration