The Abnormalities of Nucleic Acid Metabolism in the Anthers of the Nuclear Male Sterile TAIGU Wheat Plants

Comparative studies were made on the mucleic acid metabolism in the anthers of the muclear male sterile Taigu wheat and its normal fertile counterpart at various developmental stages. Starting from reduction division (RD) of the pollen mother cells, abnormality of nucleic acid metabolism took place in the male sterile anthers, as expressed in the following way. First, the total content of KNA decreased to only 22.4% of the normal (Table 1). At the same time, the content of free uridine mono- phosphate (UMP ) increased to about 4 times of that in the fertile anthers (Table 2). Secondly, the activity of RNA-ase in the sterile anthers was 4 times higher than that in the fertile an- thers (Fig. 2). This is in good agreement with the first point. There was no significant diff- erence in the activity of RNA polymerase(Fig. 1). The change of RNAase in th anthers of both fertile and sterile plants was further ana- lyzed by studying the isoenzyme patterns by electrophoresis. It is interesting to note that in the electrophoretic pattern of the sterile an- thers, a new band appeared (band n) between b and c bands(Fig. 3). It was barely visible at RD stage and became more pronounced at uninuclear stage of the microspores. From the electrophoretic patterns, it can also be no- ticed that the activities of the a and b bands in the sterile anthers were much higher than the corresponding bands of the fertile anthers. It seems that the appearance of the new band and the increased activity of the originally existed isozymes were the reasons for the increased of RNase. Similar comparative studies were made on the nucleic acid metabolism of flag leaves of both kinds of plants. No significant differ- ence could be found in either the DNA or the RNA content in the flag leaves between the fertile and sterile plants. It seems that the Tal gene, the dominant gene which causes male sterility, is expressed mainly in young anthers.