摘要:

In both maple and birch saps there is significant but low glycoside hydrolase activity. Maple sap preparations were higher in invertase and lower in amylase activity than the corresponding birch preparations; invertase and amylase activity was approximately the same in the two xylem tissues. Sucrose predominates in maple sap and glucose and fructose in birch sap but this difference cannot be ascribed to enzyme activity in either the sapper seor in the xylem tissue of the tree trunks.

ISSN:0008-4026    

DOI:10.1139/b63-144

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

A new physiologic race of crown rust,Puccinia coronataCorda f. sp.avenaeErikss., was isolated from oats collected in four Canadian provinces in 1962. This race, 332, is one of the first reported that is capable of attacking both the differential oat varieties Victoria and Saia. A close relationship exists between race 332 and race 216, which suggests that the former may have arisen from the latter by mutation. The evolution of this new race has occurred in the absence of any known Saia type resistance in current commercial varieties, and its survival points up the operation of selective forces other than host resistance on the racial composition of the pathogenic population.

ISSN:0008-4026    

DOI:10.1139/b63-145

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Extracts from wheat plants infected with wheat striate mosiac virus were shown to be infective by injection into virus-free leafhoppers (Endria inimicaSay). To prepare the infective extracts, diseased plants were homogenized in phosphate-buffered saline with or without magnesium chloride and glycine, heated at 45 °C for 10 minutes, and concentrated by differential centrifugation. The virus was protected by the addition of magnesium chloride and glycine. Most of the virus was sedimented at 78,400 gfor 60 minutes but a decrease in viral activity occurred during centrifugation.

ISSN:0008-4026    

DOI:10.1139/b63-146

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

C14-labelled substrates were supplied to leaves, and the labelling patterns in derived amino acids were examined. A new technique is described for the ninhydrin decarboxylation of amino acids separated on paper chromatograms, making use of the Dynacon electrometer. Succinate-1,4-C14, succinate-2,3-C14, pyruvate-1-C14, pyruvate-2-C14, pyruvate-3-C14, C14O2, and glutamate-1-C14were supplied to wheat leaves, and the total C14and carboxyl-C14in alanine, aspartate, glutamate, asparagine, and glutamine were determined. The results indicated that the amino acids and amides were formed mainly from the corresponding Krebs cycle intermediates. Carbon entered the Krebs cycle mainly by decarboxylation of pyruvate, but partly by its carboxylation. Extensive cycling did not occur. Various other suggested pathways, including the conversion of succinate to glutamic acid via succinic semialdehyde and γ-aminobutyrate followed by carboxylation, did not occur.When glucose-UL-C14was supplied to pea or bean seedlings, the labelling pattern in alanine and glutamine indicated their derivation from glucose via glycolysis and Krebs cycle pathways. However, the pattern in asparagine indicated that it may have been formed from products of glyoxalate cycle.

ISSN:0008-4026    

DOI:10.1139/b63-147

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

The diploid swarm cell in the life cycle ofStemonitis fuscawas observed continuously following syngamy through encystment and a nuclear division to the formation of other swarmcells. Evidence is presented to show that the first diploid cell may not be the primary plasmodial cell under certain microcultural conditions.

ISSN:0008-4026    

DOI:10.1139/b63-148

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Vivipary is reported in seven plants ofBromus pumpellianusScribn. which were grown from seed collected in central Alaska. The phenomenon occurred on three occasions at Winnipeg, Manitoba, twice in the greenhouse and once in the field, and on one occasion at Palmer, Alaska, in plants grown in a light chamber. No proliferations were found in the same plants grown in the field at Palmer, Alaska. The environment under which proliferations occurred was long days, moderate temperatures, and moderately humid atmosphere. Change in daylength from that which occurs in the natural habitat was not essential to promote vivipary. The viviparous leaflets arose from maternal tissue which under normal circumstances would have become the lemmas of the spikelet.

ISSN:0008-4026    

DOI:10.1139/b63-149

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

A nutritional study ofRosellinia limoniispora, a Pyrenomycete, was made on natural and defined media to ascertain some of the factors influencing the production of perithecia in pure culture. The importance of the vitamins biotin and thiamin was determined, together with the effects of different sugars tested singly and in combination. Dextrose was the best single sugar source for fruiting, but a medium containing a combination of four or five sugars produced most perithecia in as short a period of time as any other medium except 2% malt extract. On the latter the fruiting time was distinctly shorter than on any other medium and the number of perithecia formed was still high.

ISSN:0008-4026    

DOI:10.1139/b63-150

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Roots of the bracken fern (Pteridium aquilium) isolated from a sexual sporeling have been successfully cultured in vitro. Initial studies were directed toward a definition of growth conditions and media. The roots are now cultured in a very simple medium consisting of a Knudson mineral salt solution with added minor elements and 1.5% sucrose, at an initial pH of 5.5. A striking response leading eventually to the formation of laterals was observed when indoleacetic acid was added to the medium. After prolonged culture, without transfer, some of the stock cultures on basal medium gave rise to gametophytes through the process of apospory.

ISSN:0008-4026    

DOI:10.1139/b63-151

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Under continuous illumination, floral initiation was earlier with each increase in light intensity from 200 to 2500 ft-c, and with each increase in temperature between 10 and 30 °C. This effect of light intensity is attributed to promotion of floral initiation by energy in the far-red (730 mμ).The rate of formation of leaf primordia was accelerated by increases in light intensity to a greater extent than floral initiation, so that the final leaf number on the main shoot was greatest for the plants grown at high light intensities. Between 10 and 25 °C an increase in temperature had similar effects on the rate of formation of leaf primordia and floral initiation, so that the final leaf number was not altered. The final leaf number was lower at 30 °C than at 25 °C because leaf primordium formation was retarded.After floral initiation, the growth of the apical meristem was most rapid at 30 °C and 2500 ft-c, resulting in the earliest heading and anthesis (33 and 38 days). Low temperatures strongly retarded the later stages of ear development and emergence.

ISSN:0008-4026    

DOI:10.1139/b63-152

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

The relationship between nectar production and fruitset of blueberry is not significantly strong. Measurements of nectar volume and weight of nectar sugar were not correlated with fruitset, while nectar concentration showed a significant relationshipin only 1 year out of 3. Constituent nectar sugars were not involved in the relative attractiveness to pollinators of the various blueberry clones studied or between blueberry and other plants in bloom at the same time. Pollinator attraction is inversely related to age of bloom.

ISSN:0008-4026    

DOI:10.1139/b63-153

出版商:NRC Research Press    

年代:1963

数据来源: NRC