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1. |
THE DEVELOPMENT OF TWIN EMBRYO SACS, EMBRYOS, AND ENDOSPERM INPOA ARCTICAR. BR. |
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Canadian Journal of Research,
Volume 19c,
Issue 5,
1941,
Page 135-144
V. Engelbert,
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摘要:
The origin and development of twin embryo sacs especially inP.arcticaR. Br. were studied microscopically in sections of whole spikelets representing consecutive stages in development from the time of emergence of the panicle until after pollination. Twin embryo sacs usually develop, one originating from the innermost of a row of four macrospores with the reduced chromosome number, the other from an aposporous cell that originates in the nucellus, near the chalaza and behind the normal archespore. The individual development of the normal and aposporous embryo sacs from their respective mother cells is traced and the competition between them discussed. Both aposporous and normal egg cells develop parthenogenetically. Pollen germination appears to activate the aposporous polar cell to form endosperm which in turn nourishes the aposporous (2n) and (or) the "sexual" (n) embryo. The greatest number of plants originate from the aposporous embryo. A type of apospory was found inP.alpinaL. from Greenland. The work of other investigators, especially onP.pratensisL. is reinterpreted in the light of these findings.
ISSN:1923-4287
DOI:10.1139/cjr41c-018
出版商:NRC Research Press
年代:1941
数据来源: NRC
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2. |
STERILITY IN POTATOES |
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Canadian Journal of Research,
Volume 19c,
Issue 5,
1941,
Page 145-155
T. J. Arnason,
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摘要:
Microspore tetrads were rarely formed in three male-sterile potato varieties studied. Dyads and triads were much more common. The failure of the second meiotic divisions appeared to be the main reason for the lack of tetrads. Many of the microspores aborted without enlarging, some did grow, however, and round off. In presumably mature anthers from open flowers, microspores were very variable in size and in the appearance of the nucleus and cytoplasm. Anther pores usually failed to open. The pollen-fertile varieties formed microspores that were almost entirely in tetrads. Mature anthers had roomy locules, open anther pores, and large numbers of uniform, sound-appearing pollen grains. They contained also some empty grains. About one-half the grains from one pollen-fertile line were empty. Abscission of buds and flowers is an important factor contributing to sterility or at least unfruitfulness in many potato varieties, including the three male-sterile ones reported in this paper. Following pollination with sound pollen, a few seeds have been obtained, though with some difficulty, from each of the male-sterile lines. Premature flower abscission rather than female sterility appears to be the main bar to seed production when sound pollen is applied.
ISSN:1923-4287
DOI:10.1139/cjr41c-019
出版商:NRC Research Press
年代:1941
数据来源: NRC
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3. |
A STUDY OF THE RELATIVE EFFICIENCY OF SEED SAMPLING METHODS |
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Canadian Journal of Research,
Volume 19c,
Issue 5,
1941,
Page 156-162
C. W. Leggatt,
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摘要:
Using prepared samples of seed, in which impurities were represented by stained seed of the same kind, repeated samplings from a restricted bulk were made by the method being studied. After each sample was drawn, the number of stained seeds in it was recorded and it was then put back in the bulk. The data, being in the form of numbers in a unit weight, were first compared with the corresponding Poisson distribution, which, however, was found inapplicable. Working from first principles, an expression was found that was believed to suit the conditions of the experiment and that proved to be a special case of the binomial distribution, not previously applied, it is believed, to studies of this sort.Statistical tests showed an excellent fit between observed results and the values expected according to the new expression, which thus provides a measure of the variability to be expected in drawing subsamples from a restricted bulk and at the same time provides the required basis for comparison of the seed sampling methods under study. It shows that less variation is to be expected between duplicate tests of a submitted sample than was previously thought to be the case.
ISSN:1923-4287
DOI:10.1139/cjr41c-020
出版商:NRC Research Press
年代:1941
数据来源: NRC
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4. |
CHANGES IN THE PHYSICAL PROPERTIES OF GLUTEN WITH AGING OF FLOUR |
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Canadian Journal of Research,
Volume 19c,
Issue 5,
1941,
Page 163-176
J. D. McCaig,
A. G. McCalla,
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摘要:
The physical properties of gluten, as determined by the hydration of the gluten between pH 4 and 7, are deleteriously affected by aging of flour. Similar effects are obtained by adding linolic acid, whereas some of the effects of aging can be removed by extraction of the flour with ether. The original quality of the gluten is not restored by such extraction. Gluten from aged deteriorated flour swells enormously in 0.1 Nacetic acid; such hydration is not an indication of good quality but rather of resistance to dispersion. Some freshly milled flours produce gluten possessing the physical characteristics of gluten from aged deteriorated flour.It is concluded that the quality of gluten depends to a considerable extent on the nature of the adsorbed lipoids. Many of the characteristics of gluten are determined by relatively insoluble (unidentified) lipoid substances, whereas the absence of such lipoids and the formation of fatty acids during aging are deleterious to gluten quality.
ISSN:1923-4287
DOI:10.1139/cjr41c-021
出版商:NRC Research Press
年代:1941
数据来源: NRC
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5. |
EFFECTS OF TALC DUSTS CONTAINING PHYTOHORMONE, NUTRIENT SALTS, AND AN ORGANIC MERCURIAL DISINFECTANT ON THE ROOTING OF HERBACEOUS CUTTINGS |
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Canadian Journal of Research,
Volume 19c,
Issue 5,
1941,
Page 177-182
N. H. Grace,
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摘要:
Cuttings ofColeus Blumei, varieties ofChrysanthemumand species and varieties ofIresinewere treated with a series of talc dusts containing naphthylbutyric acid, nutrient salts, and ethyl mercuric bromide and then were propagated in sand in the greenhouse. Naphthylbutyric acid treatment increased the number of roots per rooted cutting, and its combination with the mixture of nutrient salts increased fresh root weight ofColeuscuttings. Organic mercury treatment increased, by about 5%, the number ofChrysanthemumcuttings that rooted, and increased the number of roots onIresinecuttings. Beneficial effects from talc treatment alone were a feature of the results. Differential reactions to both talc and organic mercury treatments were shown by closely related varieties.
ISSN:1923-4287
DOI:10.1139/cjr41c-022
出版商:NRC Research Press
年代:1941
数据来源: NRC
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