Effects of the rays of radium on plants . effectsofraysofr1908gage Year: 1908 244 EFFECTS OF EXPOSING GERM-CELLS TO RAYS OF RADIUM The morphological asymmetry was not confined to the rosette stage, but persisted throughout the entire life of the plant, giving narrow leaves on one side of the narrow upright stem, and on the secondary branches growing in their axils, and broad leaves on the opposite side and branches (plate 7, a different plant than figure 71). Fig. 71. Onagt-a biennis. Morphological Asymmetr}'. From a Seed developed in an unexposed Ovary whose Stigma was pollinated with Pol
Effects of the rays of radium on plants . effectsofraysofr1908gage Year: 1908 244 EFFECTS OF EXPOSING GERM-CELLS TO RAYS OF RADIUM The morphological asymmetry was not confined to the rosette stage, but persisted throughout the entire life of the plant, giving narrow leaves on one side of the narrow upright stem, and on the secondary branches growing in their axils, and broad leaves on the opposite side and branches (plate 7, a different plant than figure 71). Fig. 71. Onagt-a biennis. Morphological Asymmetr}'. From a Seed developed in an unexposed Ovary whose Stigma was pollinated with Pollen exposed for 24 Hours to Rajs from Radium of 1,500,000 Activity in a sealed Glass Tube. Cf. PLATE 7. The difficulty of explanation is greater here than in the former case. The rosette (figure 71), bearing leaves of both kinds sug- gests that a fertilized egg may have been unequally influenced by the radium rays, but such a condition is excluded by the fact that only the pollen was exposed. An untreated ovary was pollinated with pollen that had been exposed for 24 hours to the rays from radium bromide of 1,500,000 activity. There seem to exist in the germ-cells of this species two factors expressed in the mature organ- ism by a different ratio between the length and breadth of the leaves. Most frequently the broad-leaved type appears, while at times, under some unrecognized environmental stimulus, the narrow-leaved form results. The radium rays may affect this unit-character in either germ-cell, and, when we recall that, after fertilization, the male and female chromatins do not fuse until synapsis immediately preceding
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