| 1. Free amino acids in the sterile anthers and leaves: A paper-chromatographic
survey of free amino acids in sterile anthers revealed the disappearance
of proline and a remarkable accumulation of asparagine during the course
of pollen degeneration (FUKASAWA 1954). This notable phenomenon was also
found in the anthers of cytoplasmic male-sterile maize (FUKASAWA 1954; KHOO
and STINSON 1957). Further, a similar difference in proline and asparagine
content has been observed between mature leaves of normal and male-sterile
plants. However, artificial sterile anthers and etiolated leaves obtained
from dark-grown durum plants showed almost the same relationships
between asparagine and proline as the male - sterile plants (FUKASAWA and
MITO 1956). 2. Sucrose and starch in sterile anthers: Anthers of normal and abortedpollen - plants may be distinguished by tde difference in sugar content as shown by paper chromatography. Sucrose is virtually absent in sterile anthers, but fructose and glucose contents are remarkably different from those in normal fertile anthers. When the young spikes of male - sterile plants were cultured in sucrose solution, they grew better than those grown in the medium without sucrose. No good pollen was produced, though the addition of sucrose to the medium was found to be efficacious to some extent in improving the microspore development (FUKASAWA, MITO and FUJIWARA 1957). In male - sterile barley, a decrease of carbohydrate content has been observed in young spikes (MOCHIZUKI and ONO 1962). A cytochemical examination of polysaccharide particles (starch grains) in anther tissues revealed that the parietal cells of sterile anthers have small and decreased particles in comparison with those of normal fertile anthers. 3. Succinic dehydrogenase activity and respiration: Succinic dehydrogenase activity of anthers and germinating embryos has been measured by means of reduction of triphenyl tetrazolium chloride (TTC) to its red formazan. Sterile anthers showed fairly lower activity of the enzyme than the normal ones, not only in the pollen - degenerating period, but also at the meiotic stage. In experiments with germinating embryos, no difference was observed between the enzyme activities in normal and male sterile strains (FUKASAWA 1961). Further, the respiratory capacity was measured manometrically in the homogenate of germinating embryos, resulting in no different amount of O2-uptake between normal and male - sterile strains. Inhibitory experiments by application of acridine, however, have indicated a higher sensitivity in the sterile strain than in the normal plants. |
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