稲の葉緑素突然変異体における生長および光合成の特性について

抄録

In artificial chlorophyll mutants (albina, xantha, viridis, striata and tigrina) of rice and their parent, a cultivar, Norin-8 (0ryza.sativa L.), several growth and photosynthetic parameters were measured and compared with each other. The following results were obtained: (1) Albina (CM-33, CM-35 and CM-53) and xantha (CM-123 and CM-213) mutants possessed no chlorophylls except for CM-123, one of xantha mutants with a small amount of chlorophyll. These mutnats including CM--123 were lethal after the fourth leaf stage. Viridis (MGS-359, MGS-859 and CMV-44) and tigrina (M-501) mutants were survival, but their dry weights and ear weights were less than their parent, normal rice plant (Norin-8). The other strains, M-516 (striata) and M-511 (viridis), showed almost normal growth patterns. (2) The chlorophyll contents of three viridis strains (MGS-359, MGS-859 and CMV-44) were about half or below of the normal type, especially deficient in chlorophyll b. The ratio of chlorophyll a to b in these viridis types was 9-20 as compared with about 3 in the normal. Also, they showed the higher levels of carotenoid than the normal plants. (3) 0n a chlorophyll basis, three viridis strains have about 1.7 to 3.0 times higher net photosynthetic rate than leaves of the normal rice. The photosynthetic rate on a leaf area basis was the same or slightly low for mutant and normal leaves. Also, the Hill reaction activities on a chlorophyll basis in the Chloroplast suspensions from mutant leaves were about 2 times of normal. The high net photosynthetic rate seems to be directly related to the lower chlorophyll contents of the mutant leaves. (4) The leaf blade in three viridis strains had a reduced thickness compared with normal plants and their spectral absorbance was below that of the normal leaves throughout the visible spectrum, especially in near 550, 600, and 650 nm