摘要:

The cell wall ofAmoebidium parasiticumCienk. has been investigated by staining techniques and a chemical analysis of isolated wall preparations. The wall, prepared by mechanical rupture in a Virtis homogenizer, was hydrolyzed with various acids and the components of the hydrolysate qualitatively determined by chromatography with known standards. Quantitative results suggest that the wall contains 30% galactosamine, 10% galactose, 3% xylose, 30% protein, and 4% ash. The protein estimate is based on the assumption that the nitrogen not bound in galactosamine is protein nitrogen. No evidence for the presence of chitin or cellulose was found.

ISSN:0008-4026    

DOI:10.1139/b65-096

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

Inoculum type was an important factor in pathogenicity studies ofHypoxylon pruinatum(Klotzsche) Cke. onPopulus tremuloidesMichx. The percentages of infection from bark meal and mycelial inocula were superior to that from agar plug inoculum, irrespective of whether the bark wounds were superficial or exposed the cambium and xylem. In experiments with mycelial inoculum it was demonstrated that autoclaved and living bark without inhibiting microorganisms were favorable to the growth of the pathogen. However, mycelial growth and infection were prevented when an abundance of bark saprophytes was applied to the host before inoculation. It appeared that the susceptibility or resistance of living bark to infection may have been more closely related to microbiological than chemical factors of the host tissues.

ISSN:0008-4026    

DOI:10.1139/b65-097

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

This paper examines the claim by Galston and Dalberg (Am. J. Botany, 41, 373 (1954), that IAA-oxidase is an adaptive enzyme, by which was meant that it is an enzyme formed as a consequence of the presence of IAA. Certain of the published evidence is rejected as irrelevant to the question.It is shown here that crude IAA-oxidase preparations from etiolated pea buds show a lag phase in IAA destruction whereas this is not so with enzyme from hook tissue or older stem tissue.Pretreatment of hook tissue or older tissue with IAA did not increase IAA-oxidase activity. It is confirmed that IAA-oxidase preparations from buds pretreated with IAA gave more destruction of IAA, when measured after 60 minutes, than did enzyme from untreated buds. This difference occurred because of elimination of the lag phase in destruction and not because of induced formation of enzyme.The lag phase in IAA-oxidase activity with enzyme extracted from buds was increased by exposing the seedlings to 3 minutes of weak green light (maximum transmission 520 mμ) at 16 hours before harvest. Pretreatment of such light-treated buds with IAA did not completely eliminate the lag phase in IAA-oxidase activity. It is suggested that these effects of green light are a new photo-effect in plants.

ISSN:0008-4026    

DOI:10.1139/b65-098

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

The rate of apparent photosynthesis of the lowbush blueberry was determined in Warburg flasks using Pardee's CO2buffers. A marked increase in rate of O2evolution occurred as the temperature was raised from 13.0 to 29.5 °C. With a constant temperature of 25.0 °C the rate of O2evolution increased as the CO2concentration increased from 0.2 to 0.8%. The young and middle-aged leaves had a higher rate of apparent photosynthesis than the older leaves. The rate was higher at a light intensity of 1000 ft-c than at 650 ft-c at a CO2concentration of 0.4%. At the higher light intensity a lowbush blueberry clone selected on the basis of superior agronomic characteristics had a significantly higher rate of apparent pholosynthesis than an average clone.

ISSN:0008-4026    

DOI:10.1139/b65-099

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

Inoculation of pruning wounds on grape with spore suspensions ofPhomopsis viticolaSacc. at different times of the year rarely resulted in more than 25% infection. In many cases, incipient lesions and even pycnidia developed shortly after inoculation, but infection did not progress further. Highest infection rates were obtained in the summer months with freshly cut wounds. Wounds that had dried out for several weeks were difficult to infect.Primary infections occurred on young, uninjured, succulent, green shoots. Their incidence and severity were dependent on the inoculum potential resulting from the previous year's infection and on the amount of precipitation in the latter half of May. Discrete primary lesions were nearly always superficial but coalescent ones were more deeply seated and often became perennial. Functional pycnidia were frequently observed in the mature layer of bark on the basal nodes and internodes of 1-year-old canes, the underlying tissues of which were not diseased. Green shoots are considered to be more important infection sites than the pruning wounds made during the dormant season in normal commercial practice.Control measures should include propagation and planting of clean nursery stock as well as a pre-bloom spray program. If the disease becomes established in arms or trunk it is more effective and economical to remove and renew the vine at ground level than to try to save part of an affected vine at a greater risk of reinfection.

ISSN:0008-4026    

DOI:10.1139/b65-100

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

A new monotypic hyphomycetous genus,Varicosporina, typeV. ramulosa, is described from the marine environment. Isolation of the fungus on plant material from estuarine localities in North Carolina and Florida shows the wide range of occurrence of the organism in the sea.

ISSN:0008-4026    

DOI:10.1139/b65-101

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

Extremely early flowering (production of staminate strobili 88 days from germination) of Arizona cypress (Cupressus arizonicaGreene) was obtained with foliar application of gibberellin A3commencing at age 55 days. Trials with differing concentrations of gibberellin at various ages indicated that flower bud differentiation depends on both age and gibberellin concentration, younger seedlings requiring more exogenous gibberellin. Simultaneous application of two growth retardants (AMO-1618 and B-995) had no effect upon the number of flowers, but flower size was increased where B-995 and gibberellin were given together. The period of time between initial spraying and first visible appearance of staminate strobili is 23 to 25 days. On most plants 60 to 80% of the growing vegetative meristems are changed into flower buds within 60 days of the initial treatment, often resulting in over 500 flower buds on one plant. The pollen is viable.

ISSN:0008-4026    

DOI:10.1139/b65-102

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

The symbiotic fungi of three ambrosia beetles found in British Columbia have been cultured and identified.Monilia ferrugineaMathiesen-Käärik,Monilia brunneaVerrall, andTuberculariella ambrosiaen. sp. are the symbiotic fungi ofTrypodendron lineatumOliv.,Monarthrum scutellareLeConte, andPlatypus wilsoniSwaine, respectively. Descriptions of these fungi are given and their phylogeny discussed.

ISSN:0008-4026    

DOI:10.1139/b65-103

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

Morphology of the ascus and of the ascus cluster, as observed in carmine-stained, squash preparations of the contents of immature fruit bodies, is described with the aid of photomicrographs. Complications which raise questions regarding the applicability of the currently accepted scheme of ascus development are discussed. The function of the crozier, the mechanism of spore formation, and the correlation of nuclear behavior with ascus growth appear to have been misunderstood. It is concluded that the initial stages of ascus development involve complexities, the resolution of which may reveal unknown aspects of the nuclear cycle.

ISSN:0008-4026    

DOI:10.1139/b65-104

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

In soils of the Salinas watershedFusarium solaniandFusarium tricinctumwere found only in the cultivated soils. Propagules ofFusarium oxysporumwere numerous and varied in the cultivated fields but were relatively scarce and existed essentially as a single clone in the noncultivated soils. In the Castroville watershed bothF. solaniandF. oxysporumwere recovered from noncultivated soils fairly frequently.The 'Gibbosum' cultivar ofFusarhim roseum, the most frequently isolated fusarium from field soils, was less common in the noncultivated soils.Other fusaria, such asFusarium episphaeriaand some cultivars ofF. roseum, were about as numerous in the noncultivated as in the cultivated soils. The cultivation of these soils markedly affected the makeup of the fusarium populations in them.

ISSN:0008-4026    

DOI:10.1139/b65-105

出版商:NRC Research Press    

年代:1965

数据来源: NRC