キク組織培養小植物体の生育に及ぼすＯ２濃度の影響

Abstract

Chrysanthemum morifolium (C3) plantlets were cultured on 1/2 strength MS medium with 3% and without sucrose in vessels under the moistened gas with 0.04% CO2 and either 5, 10, 15 or 21% O2 (the rest being N2) . On the 20, 30 and 40th day, the dry weight increase of the plantlets was 10% O2>5% O2 ≥15% O2>21% O2 and greater in medium with 3 % than without sucrose. The other hand, the fresh weight increase of plantlets was 10% O2> 15% O2> 21% O2≥5% O2 and greater in medium without than with 3% sucrose. The dry/fresh weight ratio increased as the decrease of O2 concentrations, especially in medium with 3% than without sucrose. Shoot and root length, and leaf area of plantlets were the smallest in 5% O2 treatment, and also were significantly smaller in medium with 3% than without sucrose. Relative growth rate and relative leaf growth rate of plantlets were greater, but less net assimilation rate in 10% O2 than in 5% O2 treatment. Enhancement of the growth in C3 plantlets in vitro by low O2 will be best in 10% O2 treatment. And photoautotrophic culture of plantlets appears to be possible under low O2 treatment.