Histochemical Studies On the Cytoplamic Male-sterility of some Crops : III. Distribution of 14C-assimilates in maize

In order to clarify the common physiological causation responsible for the cytoplasmic male sterility in various crops, the authors have carried out histochemical studies on male sterile plants as compared with fertile plants. The present study describes the results of an observation of maize, Zea mays L., which inherits male sterility through cytoplasm incorporation of the chromogene. Using the 14C tracer methods, the following results were obtained on the distribution of 14C-assimilates. 1. At the microspore stage, the translocation of the photosynthates into the anther and the spikelet was obstructed in the male sterile plants. 2. In comparison with the fertile anthers, male sterile anthers have a low distribution ratio in the anionic fraction, but it has a high distribution ratio in the neutral and the cationic fractions. 3. In the fertile anther, one undetermined sugar spot was detected. A remarkable difference between fertile and sterile plants was also detected in 14C amino acids and 14C amino acids residues. 4. 14C-assimilate is incorporated into the lipid fraction in the fertile anthers, but not in the sterile anthers. On the basis of such observations, one of the causes of male sterility was surmised to be insufficient translocation of photosynthates from the rachis to the anther. This may be due to some inactivation or obstruction in the synthetic activities from the primary metabolic products to secondary ones.