摘要:

Survival curves for spores ofAspergillus flavusLink var.columnarisRaper and Fennell were obtained after their irradiation with gamma rays in the presence of Na+, K+, and Ca2+halogens. Halogens of Na+and K+sensitized the spores to the radiation and enhanced sensitization occurred as the dose of radiation was increased. Halogens of Ca2+protected the spores against a radiation dose of 25 krad but at higher doses although CaCl2was protective, CaBr2and CaI2were radiosensitizers, with CaI2the most efficient radiosensitizer.

ISSN:0008-4026    

DOI:10.1139/b72-173

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

14CO was supplied to bean leaves in light or darkness at 200–360 ppm in air. In light, CO was converted mainly to sucrose and proteins. The distribution of14C among products suggested that most of the absorbed CO was reduced and incorporated into serine and this was converted to sucrose. Some CO was oxidized to CO2, part of which may have been refixed as such in photosynthesis, but this was not the major pathway of light CO metabolism. In darkness, CO was absorbed nearly as fast as in light but was almost completely converted to CO2and released.Light CO fixation by leaves of a number of species was measured using 1–10 ppm CO in air. Rates varied between 0 and 0.25 μmole/dm2per hour. Rates were roughly proportional to CO concentration, but were unrelated to rates of photosynthesis. CO reduced or abolished CO2fixation in some leaves. CO fixation by vegetation of intermediate CO-fixing capacity is calculated to be in the order of 12–120 kg/km2ground per day, which approaches rates found for soil using much higher CO levels.

ISSN:0008-4026    

DOI:10.1139/b72-174

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Chromosome numbers and meiotic behavior are reported for 99 collections of grasses representing 47 genera and 88 species. First chromosome counts are reported for the following 20 species:Aristida laxa, n = 22;Chloris ekmanii, n = 20;Chusquea scandens, n = 20;Danthonia domingensis, n = 18;Eragrostis hypnoides, n = 10;E. prolifera, n = 20;Festuca mirabilis, n = 14;Leptochloa scabra, n = 30;Manisuris ramosa, n = 18;Paspalum carinatnm, n = 40;P. distortum, n = 10;Pharus glaber, n = 12;Raddia sympodica, 2n = 22;Raddiella nana, n = 10;Schizachyrium gracile, n = 20;Setaria crus-ardeae, n = 18;Thrasya paspaloides, n = 20;Trachypogon ligularis, n = 10;Trichachne laxa, n = 18;Tristachya avenacea, n = 24. The count forRaddiella nanarepresents a first generic report. Counts that differ from previous counts for the same taxon are reported for these 11 species:Andropogon gerardii, n = 40;Aristida orizabensis, n = 22;Eragrostis trichocolea, n = 30;Ichnanthus nemoralis, n = 10;Microchloa kunthii, n = 22;Olyra latifolia, n = 22;Panicum cyanescens, n = 27;Paspalum caespitosum, n = 10;P. millegrana, n = 20, 30;Schizachyrium hirtiflorum, n = 20;Trachypogon montufari, n = 30.

ISSN:0008-4026    

DOI:10.1139/b72-175

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Effused and isolated stromata ofEutypella parasiticawere delimited by zone lines and contained ascogonial coils intermixed with mature perithecia throughout the year. The imperfect state was associated with perithecia in red maple and Norway maple bark but was not found in sugar maple bark. Conidial pustules were closed or variously opened labyrinthiform structures without a distinct wall and contained conidia 24–29 × 1–1.5 μ. The imperfect state was characteristic of both the form-genusCytosporinaand the form-genusLibertella.

ISSN:0008-4026    

DOI:10.1139/b72-176

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Observations on eight autoecious species ofPucciniaon Heliantheae provide distributional extensions and additions to life cycles.

ISSN:0008-4026    

DOI:10.1139/b72-177

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Conidium ontogeny inTorulomyces lagenaDelitsch andMonocillium indicumSaksena, the type species ofTorulotnycesandMonocilliumrespectively, is analyzed by time-lapse photomicrography. The nuclear configurations occurring during conidiogenesis are also described. Since their development and karyology are essentially identical and their morphology closely similar, we consider them congeneric.Monocillium indicumis accordingly transferred toTorulomyces.

ISSN:0008-4026    

DOI:10.1139/b72-178

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

When treated with ethylene, mature fruits of the squirting cucumber (Ecballium elaterium(L.) A. Rich) abscind and dehisce prematurely. Abscission of male flowers is also accelerated by ethylene. Visible signs of senescence, a rise in ethylene production, and reduced carbon dioxide production always precede abscission or dehiscence in untreated fruits and flowers. The amounts of diffusible cellulase increase in tissues on both sides of the fruit abscission zone after exposure to ethylene. Anatomical features of this abscission zone are described.The leaves ofEcballiumdo not abscind although the blade and petiole produce large amounts of ethylene at senescence, nor do they separate when ethylene is supplied. Ethylene treatment of attached fruit peduncles accelerates their rate of elongation in the growing zone below the apical hook. The regulation of growth and abscission in these organs is discussed.

ISSN:0008-4026    

DOI:10.1139/b72-179

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Leaf extracts of pepper, geranium, and jimsonweed inhibited the development of local lesions induced by tobacco mosaic virus (TMV) on Pinto bean leaves when mixed with the inoculum; sprayed on the underside of the leaf before inoculation of the upper surface; or sprayed on the upper leaf surface after inoculation. The extracts also inhibited lesion development on the primary leaf opposite to the one on which they were applied. The inhibitory activity of the geranium and pepper extracts was separated into two fractions; one with a molecular weight greater than 50 000 and one with a molecular weight range of 1000–50 000. The inhibitory activity of the jimsonweed extract was present in the high molecular weight fraction only. The high molecular weight fraction from pepper was inhibitory when applied to the underside of the leaf. This evidence, and that supplied by the jimsonweed extract, indicates that high molecular weight fractions are capable of inducing a systemic resistance even when applied to uninjured tissue.

ISSN:0008-4026    

DOI:10.1139/b72-180

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

The complement of soluble proteins contained in the five annual leaf sets and the apical region of the shoot of cinnamon fern,Osmunda cinnamomeaL., has been determined using disc electrophoresis. The apical region and the very young leaf primordia contained high and comparable numbers of soluble proteins. Older primordia and mature leaves contained progressively fewer soluble proteins, except that the number of proteins increased in the oldest sets of leaves. These findings are discussed in relation to the results reported for the leaves of some flowering plants.

ISSN:0008-4026    

DOI:10.1139/b72-181

出版商:NRC Research Press    

年代:1972

数据来源: NRC

摘要:

Similar changes occurred in the ultrastructure of host cell organelles in the rust-infected tissues of both flax and sunflower. Up to the onset of sporulation at 8 days after inoculation the only major alteration in cell structure was a marked tendency for the cell organelles to be aggregated around the intracellular fungal haustorium and an accumulation of starch in the plastids. During sporulation, however, some striking changes occurred in the structure of plastids, mitochondria, and microbodies. Eleven days after inoculation, in a zone of host tissue adjacent to the rust pustule, the plastids no longer contained starch and varied in structure even within a single cell. Some were similar to normal chloroplasts, others had larger grana, and some bore a close resemblance to chromoplasts. In sunflower, but not in flax, mitochondria contained atypical plate-like cristae in addition to the usual vesiculate type. The micro-bodies of both plant species all contained crystalline cores in contrast to earlier stages in the disease where crystals were only occasionally detected. The plastids were also altered considerably in another zone of tissue situated beneath the rust pustule. In some plastids the thylakoids extended along their long axis, forming several large grana, and in others the large grana were interconnected by lamellae arranged in a vesicular or tubular configuration. Frequently the starch grains in these plastids were broken down into small rosettes of darkly staining particles with an appearance similar to that of animal glycogen.

ISSN:0008-4026    

DOI:10.1139/b72-182

出版商:NRC Research Press    

年代:1972

数据来源: NRC