摘要:

Two stages of damage were observed in the respiration of tobacco leaf tissues after fumigation with ozone. A damaging dose of ozone initially inhibited the respiration of fumigated leaves and of mitochondria removed from them.Stimulation of leaf respiration occurred later together with visible signs of damage and inhibition of photosynthesis. Mitochondria prepared from such visibly damaged tissue also showed stimulated activity. However, their cytochrome oxidase activity was inhibited and their oxidative phosphorylation was suppressed, like known effects of cyanide and carbon monoxide.

ISSN:0008-4026    

DOI:10.1139/b65-044

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

This report deals with the rate and amount of elongation of fusiform initials in the cycle of cell elongation and multiplication by pseudotransverse division which accompanies circumferential expansion of the cambium. In the recent growth of mature trees the yearly amount of cambial cell elongation drops as ring width decreases, but not in proportion to the decline in ring width. The cumulative elongation through lineal series of cells, per centimeter of xylem increment, increases as ring width decreases. The amount of cell elongation during the production of several narrow rings greatly exceeds that through a single wide ring having the same total width. It seems clear that the time factor is important in the elongation of cambial cells, and to some extent the interrelated frequency of anticlinal division, particularly when radial growth declines.

ISSN:0008-4026    

DOI:10.1139/b65-045

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

Fuscous blight (Xanthomonas phaseolivar.fuscans), a new disease of field beans in Canada, was found to be present in a high proportion of bean seed samples from southwestern Ontario. Although symptoms of the disease are similar to those of common blight (Xanthomonas phaseoli), a greater intensity in color is apparent on infected seed and more hypertrophy, especially of nodal tissues, is caused by fuscous blight than by common blight. In epidemiological studies in the field, it was found that seed infection as low as 0.5% could cause a serious epiphytotic in the resulting crop. This points out the necessity of a zero tolerance for fuscous blight in valuable seed stocks. Furthermore the rapid phage plaque method can be used to determine zero tolerance. Garden varieties were generally more susceptible to the pathogen than field varieties. Great Northern showed the highest degree of resistance to the disease of all the varieties tested.An agar plating technique was developed whereby the organism can be isolated and identified in infected bean seed by the production of a brown diffusible pigment on nutrient agar. A bacteriophage spot test is also described which can also be used to identify the pathogen from infected bean seed. By means of phage typing, the relationship ofX. phaseolivar.fuscans, X.phaseoli, and intermediate strains is shown.

ISSN:0008-4026    

DOI:10.1139/b65-046

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

Kalanchoe blossfeldianavariety Tom Thumb was treated photoperiodically in regular and CO2-free air and examined at two widely separated time intervals for interrelationships among flowering, succulence, capacity for CO2dark-fixation, and organic acid formation. These processes and leaf thickening are all under photoperiodic control and increase with increasing numbers of short-day treatments. They also occur in a CO2-free atmosphere on 9-hour photoperiods although CO2dark-fixation and organic acid formation are limited to the low level of the long-day treated plants at 5 weeks' time. Only CO2dark-fixation and organic acid formation appear to be interrelated and apparently utilize respiratory CO2if treated in a CO2-free atmosphere. This capacity to use respiratory CO2increases with maturity of the plants. Flowering does not control the development of succulence, organic acid formation, or the capacity for CO2dark-fixation. Likewise, capacity for dark-fixation and organic acid formation do not control flowering and can occur in vegetative Tom Thumb plants that do not exhibit appreciable succulence.

ISSN:0008-4026    

DOI:10.1139/b65-047

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

An attempt was made to induce transport of water in sections of roots ofLensby applying electrical potentials. The results support the conclusion that the observed water flows were moved electro-osmotically. With currents between 3 and 50 microamperes, the efficiency of water movement was found to be of the order of 20 to 80 water moles per faraday in living roots and four to six times more in killed roots. The highest efficiency coinciding with the best conductivity was observed in the zone of elongation. An asymmetry of flow upon reversal of the direction of the current was found which appeared to be linked to an asymmetry of both apparatus and plant material.

ISSN:0008-4026    

DOI:10.1139/b65-048

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

Bark extracts ofFraxinus pennsylvanicaMarsh.,F. americanaL.,F. nigraMarsh., andF. excelsiorL. inhibited the growth ofBacillus cereusFrank. and Frank. in culture. Activity varied according to the sections of the stem and the species used. Extracts ofF. pennsylvanicawere most active. Thin-layer chromatograms and ultraviolet and infrared spectra of purified substances from bark extracts revealed two types of active compounds. On this basis the four species were separated in two taxonomically distinct groups which corresponded to the subsection of the genusFraxinusproposed by Endlicher on morphological bases. The active compounds were identified as glycosides.

ISSN:0008-4026    

DOI:10.1139/b65-049

出版商:NRC Research Press    

年代:1965

数据来源: NRC

ISSN:0008-4026    

DOI:10.1139/b65-050

出版商:NRC Research Press    

年代:1965

数据来源: NRC

ISSN:0008-4026    

DOI:10.1139/b65-051

出版商:NRC Research Press    

年代:1965

数据来源: NRC

ISSN:0008-4026    

DOI:10.1139/b65-052

出版商:NRC Research Press    

年代:1965

数据来源: NRC

ISSN:0008-4026    

DOI:10.1139/b65-053

出版商:NRC Research Press    

年代:1965

数据来源: NRC