Abstract
The relationship between the directional growth of lateral buds and the auxin in shoot apices of potato seedling was studied and the results obtained were summarized as follows, 1. The directional growth of lateral buds in potato seedling was charactarized as follows : coty. - 4th node - downward growth, 5th & 6th node - horizontal growth, above than 7th node - upward growth. 2. The downward growth of lateral buds was suggested to be determined morphologically with two factors, increase of cell length and cell number in upper side of lateral bud. 3. The directional growth of lateral buds changed from downward to upward, with removal of the shoot apices. 4. The role of shoot apices was suggested to be combined with auxin in shoot apices. 5. Endogenous IAA activity (Rf 0.4-0.5) in upper parts of seedling was higher than that in lower parts.
