Cryptic mutational variability of plants and the effect of phytohormones on its penetrance
1991
Privalov, G.F. | Yakovleva, I.A.
Investigations of the modifying effect of gibberellic acid (GA3) on radiation-induced mutational variability of tomato plants showed that not all types of mutations are phenotypically penetrant in given growth conditions. Treatment of seeds with GA3 sometimes induces the appearance of additional recessive mutations specific for given sets of conditions. Treatment of plants heterozygous for the recessive Wiry gene ("whisker-like" leaves) with GA3 increased the frequency of this type of mutation from 0.53% in the control to 2.35%. GA3 thus increases the phenotypic penetrance of the recessive Wiry gene, despite the presence of the dominant allele which produces the normal phenotype. Combined treatment of seeds from the mutual tomato line "Wilty dwarf," which is homozygous for the recessive wd gene, with gamma-rays and GA3 showed that GA3 significantly reduced the penetrance of dominant (WD) mutations (i.e., of reversions to normal) induced by gamma-irradiation. It was shown that increases in the content of GA3 in plant cells has opposite effects on the penetrance of several recessive and dominant markers, stimulating the penetrance of recessive markers, and reducing that of dominant markers.
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