. Genetics in relation to agriculture. Livestock; Heredity; Variation (Biology); Plant breeding. FiG. 11.—0, Portion of leaf of parental Scrophularia showing branching lateral vein; D, branching vein replaced by two laterals in leaf of a seedling grown from seed produced by an injected ovary. Also note difference in size and margin of leaves. (After Alac Dougal.) tinct strains or biotypes which remained constant for hundreds of test- tube "; It must be admitted that in most of these cases no specific influence can be named as the direct cause of the inherited variation. B
. Genetics in relation to agriculture. Livestock; Heredity; Variation (Biology); Plant breeding. FiG. 11.—0, Portion of leaf of parental Scrophularia showing branching lateral vein; D, branching vein replaced by two laterals in leaf of a seedling grown from seed produced by an injected ovary. Also note difference in size and margin of leaves. (After Alac Dougal.) tinct strains or biotypes which remained constant for hundreds of test- tube "; It must be admitted that in most of these cases no specific influence can be named as the direct cause of the inherited variation. But there is no longer any doubt that permanent, discon- tinuous variations do occur spontaneously in these lowest organisms, and it is highly probable that certain incidental, external forces play an im- portant part in inducing such variations. Direct experimental attack upon the germ cells themselves has been made with plants by a number of investigators, notably b}^ Mac- Dougal, who injected very dilute solutions of potassium iodide, zinc sulphate, sugar, etc., directly into the ovaries of various plants imme- diately before fertilization. Consequently somatic changes have been produced which were inherited throughout several generations. By means of check experiments and observations it was found that these germinal variations were not caused by the wounding of the ovary and it is thought that they must have been induced in some way by the presence of the foreign chemical solution in the ovary. Fig. 11 shows a mor- phological change which appeared in a seedling of an unnamed species Digitized by ®. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Babcock, E. B. (Ernest Brown), b. 1877; Clausen, Roy Elwood, 1891-. New York, McGraw-Hill; [etc. , etc. ]
Size: 1816px × 1376px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksu, booksubjectplantbreeding
