Dalby A, Davies I I
Science. 1967 Mar 24;155(3769):1573-5. doi: 10.1126/science.155.3769.1573.
During development, the ribonuclease activity of maize endo sperm homozygous for the opaque-2 gene increased earlier and, after a longer period of exponential increase, was much higher finally than in normal endosperm. The maximum difference was about sixfold and occurred 22 to 25 days after pollination. Heterozygotes on day 23 did not show a comparable in crease in endosperm activity. No differ ence in the activity ratio (pH 6.0: pH 5.2) was found between normal and opaque-2 endosperm, indicating that the increase in activity in opaque-2 was due solely to an increase in ribo nuclease A. The ribonuclease activity of opaque-2 embryos increased more rapidly than that of normal embryos, but the final activity was the same in each case.
在发育过程中，对于不透明-2基因纯合的玉米胚乳的核糖核酸酶活性更早增加，并且在较长时间的指数增长期后，最终比正常胚乳中的活性高得多。最大差异约为六倍，出现在授粉后22至25天。在第23天的杂合子中，胚乳活性没有出现类似的增加。在正常胚乳和不透明-2胚乳之间未发现活性比率（pH 6.0：pH 5.2）的差异，这表明不透明-2中活性的增加仅归因于核糖核酸酶A的增加。不透明-2胚胎的核糖核酸酶活性比正常胚胎增加得更快，但最终活性在每种情况下都是相同的。
