Springer Online Journal Archives 1860-2000
Summary 1. Gibberellic acid caused a considerable decrease of fertility and some other morphological anomalies in barley plants. The present investigations were carried out to prove whether there is a special sensitive phase for these reactions in plant development. 2. By time-gradual application (spraying daily with GA3, 100 ppm) we observed in all varieties tested — Haisa, mutant MS 1196, mutant MS 733 —a sensitive period around the 30th day after beginning the experiments (two-leaves stage). None of the other application variants showed similar effects (Figs. 1–7). 3. Cytological investigations have proved that GA has no influence on chromosomes and meiosis. There is, however, a marked effect on pollen formation when application is carried out during the sensitive period (Figs. 8–11). Several degrees of pollen degeneration were found which lead to sterility. Femal gametes seem not to be affected. 4. It is discussed whether the characters mentioned above are directly or indirectly effected by GA and whether GA can be used as a possible gametocide in barley breeding. Some remarks are given on the problems which are concerned with the species or varietal specificity of the sterility effect caused by GA.
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