摘要:

One-year-old virus-free sour cherry trees of the variety Montmorency were inoculated singly with buds from different source trees infected with sour cherry yellows, necrotic ring spot, prune dwarf, and tatter leaf respectively. The infections thus established in the test trees were later challenged by inoculation with isolates from different sources. Conspicuous recurrent symptoms occurred when infection from a tatter leaf isolate was challenged by either of two necrotic ring spot virus strains, but not when the order of challenge was reversed. These symptoms are interpreted as a synergistic response to infection by two viruses, one from each source, within a limited range of interaction. Trees previously infected with necrotic ring spot when reinoculated with cherry yellows isolates showed symptoms of cherry yellows, usually preceded by secondary shock. The reciprocal challenges, on the other hand, induced no symptoms of necrotic ring spot, probably because each of the cherry yellows sources carried a strain of the necrotic ring spot virus. There were indications, however, of interference between the two viruses. Infection with the prune dwarf virus did not protect against subsequent infection with the cherry yellows virus. Mixed infections with the necrotic ring spot and prune dwarf viruses did not cause cherry yellows.

ISSN:0008-4026    

DOI:10.1139/b62-094

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

Silverberry (Elaeagnus commutataBernh.) is of some importance as an ornamental shrub and in certain areas is a rangeland weed. Various germination tests over a 2-year period showed that unstratified seeds of this species, within intact endocarps, germinated 0 to 20% in 10 days, and 0 to 45% within 20 days, on moist filter paper in Petri dishes in the dark at 20 °C. After stratification of such seed in moist sand at 5 °C, for periods of 40 to 110 days, the germination percentages ranged from about 23% to 75% respectively. Removal of the endocarps, however, from unstratified seeds resulted in 85 to 100% germination within 10 days. A water-soluble extract from the endocarps retarded growth of wheat seedlings and of seedlings from naked silverberry seeds but did not reduce percentage germination. Self-controlled embryo dormancy is apparently not a major factor causing delayed germination of the silverberry.Supplementary tests involving heat treatments, or soaking of the unstratified fruits in gibberellin or KNO3solutions, were without effect on germination of silverberry seed from within its endocarp.

ISSN:0008-4026    

DOI:10.1139/b62-095

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

The relationships between width of annual rings, length of wood cells, and frequency of anticlinal (multiplicative) divisions in fusiform cambial cells were studied by reference to trees of various growth patterns. The trees selected ranged from 8 to 20 in. diameter and included both open-grown specimens with branches close to the ground and forest types with tall, slender shafts. Much fluctuation was noted among individual trees, but in general there was, in the peripheral growth, an inverse relationship between length of wood cells and width of annual rings. The frequency of anticlinal divisions in the cambium remained at a more or less uniform rate in trees with rings from 1.5 to 5 mm wide, but rose sharply when ring width fell below 1.3 mm. This was in contrast to the situation observed earlier inThuja occidentaliswhere the rise in frequency of anticlinal divisions was slight and occurred only in trees with rings less than 0.3 mm wide.

ISSN:0008-4026    

DOI:10.1139/b62-096

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

Dendrographs attached to the lower boles of large trees of several species indicated little change in diametral fluctuation patterns following decapitation or severe mechanical interruption of conducting tissues. Treated and undisturbed stems of a particular species, investigated concurrently, manifested striking similarities in the amount, trend, and duration of diameter shrinkage. The results of these experiments, in company with others dealing with continued moisture movement in experimentally treated trees, jointly suggest that the water-conducting system of large wood stems is one of great coherency and stability.

ISSN:0008-4026    

DOI:10.1139/b62-097

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

The physiology of three groups of morphologically similar wood-rotting polypores, which produce extracellular oxidases as indicated by positive reactions with guaiacol, was studied comparatively.The inability to oxidize tyrosine and phenols, including guaiacol, in 'spot tests' distinguishedP. cinnabarinus(Jacq. ex Fr.) Karst. fromP. sanguineus(L. ex Fr.) Murr. andP. coccineus(Fr.) Bond. and Sing. growing on a tyrosine medium.The possible application of these methods for obtaining more specific distinctions within the two larger groups, the 'guaiacum-positive', lignin-decomposing and the 'guaiacum-negative' organisms, is indicated.The three groups separated on the basis of differential growth on malt extract agar at 35.2 °C.P. cinnabarinusgrew slower generally thanP. sanguineusandP. coccineuson malt extract agar between 20 °C and 40 °C and on various nitrogenous and phenolic substrates.There were indications that differences in the history of the isolates might have been a factor contributing to the intraspecific variations observed in growth and pigmentation.The pigments obtained from malt extract cultures of the three groups were the same.Eighteen, out of a total of 41 different ninhydrin-reacting compounds, were common to all isolates of the three groups grown in asparagine medium. Three compounds were specific to certain groups and 20 were distributed randomly between the isolates.

ISSN:0008-4026    

DOI:10.1139/b62-098

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

Three kinds of variability in the Rocky Mountain flora of Alberta are considered. The flora is composed of species with two gross distribution patterns: the boreal element and the cordilleran element. There are minor floristic differences from valley to valley; such differences involve the sporadic occurrence of certain species in different valleys. Main consideration is given to another type of floristic variability which involves a major floristic difference between the southern part of the mountain region and the northern part.The Crowsnest–Waterton area in the southern part of Alberta is distinctive climatically and phytosociologically from the rest of the Rocky Mountain region of Alberta. Moreover, a large number of plant species and some animal taxa occur in Alberta only in this area. Two possible features are suggested as being responsible for the distinctiveness of the southern area: the climatic effects of the occurrence of the area within a major storm track; and the existence of an adjacent unglaciated area which, during Pleistocene, could have served as a refugium for taxa which subsequently expanded in the southern area.

ISSN:0008-4026    

DOI:10.1139/b62-099

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

The sugar and amino acid content of six tomato varieties were compared by paper chromatographic methods. These varieties reacted to race 1 ofCladosporium fulvumCke. as follows: Potentate, susceptible; V-121 and Stirling Castle, resistant; Vetomold, Vinequeen, andLycopersicon pimpinellifolium(Jusl.) Mill., immune. Potentate, Vetomold, and V-121 are closely related genetically, the last two having been developed by repeated backcrossing to Potentate of immune and resistant segregates from Potentate ×L. pimpinellifoliumcrosses. The resistance of Stirling Castle is controlled by a gene different from the gene which conditions immunity in Vetomold and one that confers resistance on V-121, while the immunity of Vinequeen stems fromL. hirsutumHumb. and Bonpl.Fructose, glucose, and sucrose occurred in all varieties, but, among the three closely related ones, the consistently low level of all three in V-121 and the low fructose in Red Currant were suggestive, while Potentate and Vetomold displayed reciprocal levels of fructose and sucrose. The two resistant varieties differed in sugar content and the three immune ones were not consistent.From four sets of extracts of all six varieties, grown under conditions optimal for disease expression, 15 amino acids were identified. The relative amounts of these differed significantly in different varieties without, however, any general causal relation to resistance being evident. The consistently lower levels of one or more of aspartic acid, serine, and glutamine in V-121 may be significant in limiting the development of the fungus in this resistant variety. The immunity of Vetomold did not seem to be conditioned by the presence or absence of specific amino acids nor did the immunity of Vinequeen. When extracts of this sort were compared with extracts from plants grown under a light experience reduced sufficiently to disturb the host–parasite relations, it was evident that this treatment significantly altered both the sugar and amino acid content of the varieties in characteristic varietal patterns. This may suggest that a suitable C/N ratio is prerequisite to compatibility. The desirability of further studies is indicated.

ISSN:0008-4026    

DOI:10.1139/b62-100

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

A clone of excised tomato roots, selected originally for its marked requirement for vitamin B6, has been maintained in continuous culture in pyridoxin-containing medium since 1956. Growth in pyridoxin-free medium is now considerably greater than when the clone was originally isolated. A subclone of this clone was isolated in 1957 and maintained in medium in which pyridoxin was replaced with ethanolamine. This subclone does not show the change in response to pyridoxin deficiency. Because of this and other evidence it is concluded that the change occurs because of a change in the clone and is not an artefact due to faulty technique.The result is discussed in relation to (a) other reported changes in tissue cultures including the phenomenon of "adaptation" (accoutumance) to indole acetic acid, (b) the cellular control of metabolism.

ISSN:0008-4026    

DOI:10.1139/b62-101

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

The somatic (2n) chromosome numbers of more than 70 species of 28 genera of grasses from Bolivia, Argentina, Chile, and Uruguay are recorded. The chromosome numbers of about half of these species have not been reported in previous cytotaxonomic literature. The 28 genera areAgrostis, Aira, Andropogon, Apera, Arrhenatherum, Briza, Bromus, Cenchrus, Chloris, Cynodon, Danthonia, Eragrostis, Festuca, Gastridium, Koeleria, Melica, Nassella, Paspalum, Phalaris, Poa, Polypogon, Rottboellia, Schismus, Setaria, Sporobolus, Stipa, Trichachne, andTrichloris.

ISSN:0008-4026    

DOI:10.1139/b62-102

出版商:NRC Research Press    

年代:1962

数据来源: NRC

摘要:

Pinus strobusorP. resinosaseedlings, 2 or 3 years old, were illuminated in a closed chamber for 1 hour in the presence of C14O2. This was followed by various periods up to 24 hours under different conditions of light and darkness. Then each seedling was divided into its shoot, stem, and roots, and these were extracted separately with 80% ethanol. The extracts were resolved first on resins into sugar, amino acid, and organic acid fractions and then resolved further by paper chromatography. The C14content of various fractions and of the eluted compounds was determined by plating and counting their aliquots. Ethanol-insoluble residue was oxidized and counted as BaC14O3.Eight hours after administration of the C14O2, 91 to 94% of the total C14was found in the ethanol-soluble fractions of shoot, stem, or root. In shoots sugars were found to represent more than 95% of the ethanol-soluble photosynthate, with sucrose forming three-quarters of it. In stem and roots sucrose represented from 75 to 94% of the translocated photosynthate. Raffinose, glucose, and fructose were present in both stem and root.Seedlings with poorly developed root systems translocated less photosynthate to roots than those with good roots. Seedlings, which prior to the experiments were grown in full sunlight or 2500 ft-c artificial illumination translocated more photosynthate to roots than those grown in 6% of full sunlight or 250 ft-c artificial light. Stronger light during translocation itself also had a slight stimulatory effect.Seedlings, which were illuminated in the presence of C14O2for 1 hour and then retained in a closed chamber for a further period of 7 hours, translocated a larger fraction of absorbed C14to their roots than comparable seedlings transferred to air after feeding C14O2.

ISSN:0008-4026    

DOI:10.1139/b62-103

出版商:NRC Research Press    

年代:1962

数据来源: NRC