Year: 1981
Type: article
Abstract: In order to clarify the mechanism of the growth of an apple shoot, the authors aseptically cultured shoot apices (about 0.5mm in length) on an agar medium con taining Murashige and Skoog′s inorganic and organic substances. The effect of growth regulators and sucrose on the growth of the shoot apex was investigated. The results are summarized as follows.1. The effect of α-Naphthaleneacetic acid (NAA) was not observed in the differ entiation and elongation of leaves, and the growth of the shoot apex was inhibited by high concentration of NAA.2. The differentiation and elongation of leaves was enhanced on a culture medi um with N6-benzyladenine(BA), whereas the length and number of leaves increased according to the increase in BA concentrations within a range of 0.01 to 10μM. The apical shoots cultured on a medium with BA continued growing for six weeks. The number of leaves differentiating at 10μM BA was three fold, and the length of the longest leaf was seven fold as large as those of control respectively.3. Gibberellic acid (GA) had no effect on the internode elongation, but enhanced the differentiation and elongation of leaves. However the effectiveness of GA became stronger with the increase in concentration within a range of 0.01 to 0.1μM, and was observed slightly at above 0.1μM. But the differentiation and elongation of leaves was not enhanced by prolonging the culture period beyond four weeks. Therefore, it seemed that GA affects the growth of shoot apices within four weeks.4. In treatment of BA combined with NAA, the effectiveness of BA on the differentiation and elongation of leaves was observed at higher concentrations of NAA, suggesting that the effect of NAA was antagonistic to that of BA.5. No callus formation was obtained on a media containing NAA, BA or GA alone, but under treatment of both BA and NAA callus formation was observed remarkably. The induction and growth of callus increased with the increase of concentrations of both NAA and BA.6. The differentiation and elongation of leaves was inhibited by decreasing the sucrose concentration regardless of BA concentration. It is considered that sucrose is a limiting factor of the differentiation and elongation of leaves.
DOI: 10.2503/jjshs.49.549
Institution: Hokkaido University
Language: English
Subfield: Plant Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: diamond
OpenAlex ID: W2001561016