摘要:

Chromosome numbers and voucher specimens are recorded for some collections of the tribeTRITICEAEDumort., mainly collected in Canada. The somatic chromosome numbers of the following are recorded: (1)Elymus canadensisL., 2n = 28; (2)Elymus cinereusScribn. & Merr., 2n = 28 and 2n = 56; (3)Elymus glaucusBuckl., 2n = 28; (4a)Elymus innovatusBeal subsp.innovatus, 2n = 28; (4b)Elymus innovatusBeal subsp.velutinusBowden, 2n = 56; (5)Elymus wiegandiiFern., 2n = 28; (6)Eremopyrum triticeum(Gaertn.) Nevski, 2n = 14; (7)Sitanion hystrix(Nutt.) J. G. Smith, 2n = 28; (8) ×Agrohordeum macounii(Vasey) Lepage, 2n = 28; (9) ×Agroelymushirtiflorus(Hitchc.) Bowden,2n = 28; and (10) ×Agroelymus ungavensis(Louis-Marie) Lepage, 2n = 28. Because var.coreensisHack. is an earlier varietal name,Elymus mollisTrin. var.coreensis(Hack.) Bowden replacesE. mollisTrin. var.japonicusBowden as the name for the variety that occurs on the shores of the Sea of Japan.

ISSN:0008-4026    

DOI:10.1139/b59-094

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Unexpectedly heavy leaf rust development was observed on mature (ripe) field-grown plants of the resistant wheat varieties, Selkirk and Exchange. Greenhouse experiments with pure races of leaf rust showed that a partial breakdown of both seedling and adult plant resistance occurred when the plants were approaching maturity. This change in resistance would not affect yields but could result in exaggerated estimates of rust damage. Leaf rust readings in rust nurseries, at least on these varieties, should be made before the plants are ripe.

ISSN:0008-4026    

DOI:10.1139/b59-095

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Strain Y.4 of the cherry yellows virus was purified from cucumber by four methods, which differed mainly at the clarification stage: A, the homogenate buffered at pH 6.5 was frozen; B, leaves were frozen and the expressed sap was buffered at pH 5.0; C, fresh expressed sap was diluted with pH 5.0 buffer; D, fresh expressed sap was dialyzed against.05 Macetate buffer at pH 4.5. One or two cycles of differential centrifugation were applied after clarification. Freezing usually inactivated the virus. Methods C and D yielded infective preparations. Ultraviolet absorption spectrum analysis, and particle size and sedimentation rate determinations, supported by infectivity tests, indicated that, in these infective preparations, the virus replaced most if not all of the components found in comparable extracts from healthy sources. The agar gel diffusion technique was used for precipitin tests. Virus antigen from cucumber sources reacted with homologous antiserum or with antiserum derived from infected cherry petals and vice versa.

ISSN:0008-4026    

DOI:10.1139/b59-096

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Concentrations of 5 × 10−5 Mto 5 × 10−4 Mof 3-indoleacetic (IAA), α-naphthaleneacetic, or 2,4-dichlorophenoxyacetic acid usually reduced nectar secretion in excised flowers ofAntirrhinum majusL. cultured on sugar solutions. The major part of the reduction occurred at relatively low concentrations of the growth regulators. The percentage reduction by IAA remained fairly constant when the sugar concentration of the medium was varied. Although the growth-regulating compounds promoted ovary growth, increased growth did not appear to have been the cause of reduced nectar yields. IAA sometimes increased nectar secretion. The effect of IAA on secretion was modified by 2,3,5-triiodobenzoic acid. Nectar secretion was partially inhibited by iodoacetic acid, sodium arsenate, dinitrophenol, sodium azide, and fluoroacetic acid at concentrations which caused no visible injury to flowers. Two inhibitors of phosphate transfer, dinitrophenol and sodium arsenate, modified the influence of IAA. The data support the hypothesis that nectar secretion is an active process.

ISSN:0008-4026    

DOI:10.1139/b59-097

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

When the primary leaf of a soybean plant was allowed to carry on photosynthesis in C14O2, a small amount of labelled carbon was translocated downward into the root at a velocity of at least 5040 cm per hour. This velocity was 50 times greater than the velocity at which sucrose was translocated in the phloem. The rapidly translocated C14was not moved as carbon dioxide. When the time of translocation was increased from 30 seconds to 10 minutes there was an increase in C14content of the root without any increase in C14content of the lowest part of the stem. Part of the C14was translocated through a steam-girdled stem, but under these conditions there was no accumulation in the root. This indicates that the rapid translocation of C14occurred in both living and dead tissues of the stem. These results were correlated with the localization of C14in tissue autoradiographs of cross sections of the stem to show that there were at least three pathways of downward translocation: (a) a slow translocation in the phloem, (b) a rapid translocation in the xylem, and (c) a rapid translocation in either the cortex, the phloem, or the pith.

ISSN:0008-4026    

DOI:10.1139/b59-098

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

The photosynthetic assimilation of radioactive carbon dioxide by leaves from seven plant species was continuously measured in a closed system in which the concentration of carbon dioxide was abruptly increased from the atmospheric level to predetermined levels up to 2.0%. The rate of assimilation immediately increased, approximately proportional to concentration, but after about one minute began to decrease. The degree and duration of the decrease in rate of uptake varied with plant species and with concentration. This increased uptake of carbon dioxide influenced the distribution of carbon among the products of assimilation. At the lowest concentration (0.1%), serine, glycine, and glyceric acid contained most of the carbon assimilated during the experimental period, but at higher concentrations these were replaced by sucrose and alanine.

ISSN:0008-4026    

DOI:10.1139/b59-099

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Twin ovules, not previously reported forPrunus, occurred in from 5 to 12% of Windsor sweet cherry pistils. Rarely, twin seeds have been observed in mature fruits of other genera. The conclusions of earlier workers that twin seeds arise through fusion or fission of ovules or nucelli are not supported by the present study. Regardless of whether neither, one, or each ovule was a twin, two ovules were present in every fruit examined. Observations on the ovule development inPrunus aviumindicate that twin ovules arise by the differentiation of separate nucelli in a single ovule primordium.

ISSN:0008-4026    

DOI:10.1139/b59-100

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Cytogenetic analysis of selectedF5lines of the pentaploid hybrid, Rescue (Triticum aestivumL. emend. Thell.) × Golden Ball (T. durumDesf.) showed that chromosome XVI is the member of the D genome of Rescue that prevents transfer of the more solid top culm internode of Golden Ball to hexaploid segregates. It also produces a lax spike. Chromosome XX, which is the D-genome chromosome mainly responsible for the hollowness of hollow-stemmed hexaploids, probably has little effect in Rescue. Long awns were associated with low chromosome number but not with stem solidness or dense spike; therefore, the chromosome that suppresses awn development is probably not XVI.Three 42-chromosome segregates from the cross were more solid in the top internode than Rescue, presumably because of segregation of genes in the A and B genomes. It is unlikely, however, that a fully hexaploid segregate with a top internode as solid as that of Golden Ball can be selected from this hybrid.

ISSN:0008-4026    

DOI:10.1139/b59-101

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Chloroplasts were isolated in 0.35 MNaCl from green pea leaves. Such preparations formed ATP photosyathetically from AMP or ADP and inorganic phosphate. The conditions and cofactors of this reaction were studied. The rates of photosynthetic phosphorylation by isolated pea chloroplasts were compared with photosynthetic phosphorylation by spinach chloroplasts and with photosynthesis by intact pea leaves. The isolated pea chloroplasts also photosynthetically fixed carbon dioxide. The possible roles of chloroplasts and mitochondria in cellular phosphorylations are discussed.

ISSN:0008-4026    

DOI:10.1139/b59-102

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

This paper describes the effects produced by the metal-chelating reagent disodium versenate on the epidermal cells of living tomato roots. Striking abnormalities characterized by the disconnection or separation of every epidermal cell and by the suppression of root-hair production were consistently observed. The present study confirms the earlier observation that the epidermal cells of tomato roots are all of the "long-cell type". Individual differences in behavior of epidermal cells are based on differences in ability to incorporate calcium into their elongating walls.

ISSN:0008-4026    

DOI:10.1139/b59-103

出版商:NRC Research Press    

年代:1959

数据来源: NRC