Archive image from page 5 of A cytological study of haploid. A cytological study of haploid Crepis capillaris plants cytologicalstudy64holl Year: 1930 110 University of California Publications in Agricultural Sciences [Vol. 6 meral diploid-haploid heads. Figure 2 shows haploid and diploid heads from plant and a ehimeral head from Plant showed no evidence of diploidy above ground. Plant died before maturity. The classification of heads as dip- loid or haploid after the first large heads were shown to be diploid, with respect to PMC's at least, was made on
Archive image from page 5 of A cytological study of haploid. A cytological study of haploid Crepis capillaris plants cytologicalstudy64holl Year: 1930 110 University of California Publications in Agricultural Sciences [Vol. 6 meral diploid-haploid heads. Figure 2 shows haploid and diploid heads from plant and a ehimeral head from Plant showed no evidence of diploidy above ground. Plant died before maturity. The classification of heads as dip- loid or haploid after the first large heads were shown to be diploid, with respect to PMC's at least, was made on size alone. No achenes were produced on any of the haploid heads nor did reciprocal crosses Fig. 2. Haploid and diploid heads from one haploid Crepis mpillaris plant () and a chimera head from another (). Twice natural size. with normal C. capillaris give any achenes. Possibly more extensive trials would have resulted in success, for there was, as noted above, a small amount of apparently good pollen. However, 130 well formed achenes were obtained from the ehimeral (?) and diploid branches of plant which had been protected by a cage. The nature of Crepis pollen practically ensures selfing under such circumstances. Since the diploid tissue arose from haploid, the pairs of chromo- somes should be identical (barring mutation), and the progeny would be expected to be uniformly homozygous. In accord with expecta- tion, the progeny were very uniform. CYTOLOGICAL METHODS Root tips were fixed in Navashin's chromacetic-formalin, flower buds in the same solution preceded by treatment for several minutes with Carnoy's solution and imbedding followed in the usual manner. Other flower buds were fixed in Carnoy's solution alone, run into 70 per cent alcohol and there kept until ready for use, and examined in aceto-earmine (technique, Hollingshead 1930a). Both methods gave good pictures of meiotic chromosomes but the latter caused more cyto-
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