摘要:

An apparatus is described for growing fungi on media of defined and constant composition. The fungus grows as a surface mat on a porous, inert membrane supported on the surface of a liquid medium. A continuous flow of the medium is maintained through the growth cell to ensure its constant composition.

ISSN:0008-4026    

DOI:10.1139/b59-041

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

In the presence of ethanol or acetone at concentrations up to 10% by volume, photosynthetic fixation of C14O2byScenedesmusproceeds at nearly normal or enhanced rates, over periods of several minutes, into glycolic acid, glycine, alanine, serine, and an unknown compound. However, fixation into other compounds, such as phosphoglyceric, phosphopyruvic, and aspartic acids and the lipids, is suppressed over induction periods of several minutes. The results indicate that blocking of the photosynthetic cycle unmasks an alternate path of fixation. It is suggested that the initial step is the carboxylation of phosphoenolpyruvic acid. At a concentration of about 10−5 M,o-phenanthroline enhances the fixation into compounds which are connected with the tricarboxylic acid cycle, at the expense of the fixation in all other compounds. With increasing inhibition, alanine is in all cases the last labelled compound to vanish, as if some of it had an origin independent of that of the other products.

ISSN:0008-4026    

DOI:10.1139/b59-042

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

A rare fungus,Podosporiella verticillataO'Gara, was isolated from a single seed in each of 13 samples of common and durum wheat grown during the period 1946–1949 in western Saskatchewan and Alberta. The fungus had not been reported previously in Canada.Helminthosporium cyclopsDrechsler is a synonym ofP. verticillata. Naturally infected seed did not germinate. When mature seeds of cereals were artificially inoculated, germination was unimpaired and healthy plants were produced. Inoculation of developing kernels in heads of wheat and panicles of oats resulted in apparently healthy seeds, but when these were placed on moist filter paper they either failed to germinate or produced stunted seedlings. This injury is apparently caused by a toxin produced by the fungus. The fungus is not likely to be of economic importance under western Canadian conditions.

ISSN:0008-4026    

DOI:10.1139/b59-043

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

In a basal medium which supported good growth of two species of fungi, incorporation of "white water" was found to increase their rate of growth. Preliminary efforts to separate the active agent have been carried out, and the presence of at least two substances has been demonstrated. One of them stimulated the growth of an isolate ofPhialophora fastigiata, whilst the other stimulated the growth of an isolate ofPhomasp. The implications of the presence of these two substances in "white water" are considered.

ISSN:0008-4026    

DOI:10.1139/b59-044

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Detached leaves, leaf disks, and sterile, detached roots of tobacco were sprayed, vacuum-infiltrated, incubated, or treated with gibberellic acid to test the influence of this chemical on the breakdown of nicotine. No statistically significant differences in nicotine content were observed due to these treatments.

ISSN:0008-4026    

DOI:10.1139/b59-045

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

The morphology of the chromosomes of 16Hordeumspecies was studied in considerable detail. No obvious trend in evolution is apparent from a study of the karyotypes of the species nor are any definite relationships with common barley (H. vulgare) indicated, except for two species, usually considered as being related,H. spontaneumandH. agriocrithon. On the basis of similarities of karyotype and morphological features of the plants seven groups were formed in which relationships are evident. The groups are: vulgare, marinum, murinum, californicum, stenostachys-pusillum, bulbosum, and jubatum. The plants within each group are identified by assigned numbers and by the specific names under which they were received. Within these groups are chromosome numbers of 14 and 28 and in one case 28 and 42. Allopolyploidy is indicated for most groups butH. bulbosumexists both as a diploid and as an autotetraploid.

ISSN:0008-4026    

DOI:10.1139/b59-046

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Changes in the allantoin and allantoic acid content of germinating seedlings and aging leaves of wheat were followed. The results of experiments on photosynthetic assimilation of C14O2and the feeding of glycine-C14and glyoxylate-C14indicate that in wheat seedlings the root is probably an important site of allantoin synthesis. Glycine-C14was found to be a better precursor of allantoin-C14than glyoxylate-C14. Allantoin-C14was not synthesized from urea-C14. A scheme for allantoin synthesis which is based on these results is outlined.

ISSN:0008-4026    

DOI:10.1139/b59-047

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

An attempt is made to establish the development of the flora of Manitoba, Canada, after the complete extermination by the Wisconsin glacier of any preexisting vegetation.Based upon geology, palynology, and floristics, a theory is constructed that the ice was at first followed by a cold (marsh) grassland, covering the bottom of the drained Lake Agassiz I, and a riverine spruce (–pine) parkland of western origin, which persisted throughout the Valders period and the damming up of Lake Agassiz II. Around 9000 B.P. a deciduous forest flora started to fill in around the edges of Lake Agassiz II, and a pine–oak savanna occupied the drier portions of the upland. This flora reached its maximum north- and westwards distribution towards the peak of the Hypsithermal. Also during the Hypsithermal it is suggested that a western (–southwestern) prairie flora covered the bottom of the draining Lake Agassiz II, reaching its farthest extension towards the north and east. During the same time, the Arctic flora expanded over the Hudson's Bay Lowland. The last part to be covered by vegetation seems to have been the zone now called taiga, probably as late as 3000–4000 years ago. The spruce forest and its undervegetation seems to have arrived both from the west and from the east, and in recent times (from 2000 to 3000 B.P.) is in a stage of expansion, forcing itself into the deciduous zone, which in turn is expanding over the prairie, save for the checking activities of Man (fire and cultivation).

ISSN:0008-4026    

DOI:10.1139/b59-048

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Chromosome morphology has been described in 20 species ofAnemones. lat. (Anemones. str. 15 species,Pulsatilla3,Hepatica2). Two series, one based on 8 chromosomes and the other on 7, are present, in each of which two patterns can be recognized when an orderly arrangement of the chromosomes has been made. In the 8-chromosome series, the distinctions are based on differences in the arm ratio of chromosome IV, namely ratios of about 1:2 versus 1:1.4–1.8. Species in the first group includeA. palmata, 2n = 16;A. parviflora, 2n = 16;A. caroliniana, 2n = 16;A. silvestris, 2n = 16;A. virginiana–riparia–cylindricacomplex, (all 2n = 16);A. quinquefolia, 2n = 32; and species in the second group areA. pavonina, 2n = 16;A. coronaria, 2n = 16;A. hupehensis, 2n = 16;A. rivularis, 2n = 16;A. rupicola, 2n = 16;Pulsatilla pratensis, 2n = 16;P. nuttallianassp., 2n = 16; andP. occidentalis, 2n = 16.A. multifida, 2n = 32, has one chromosome set in each of the above groups. The 7-chromosome series falls into two groups on the basis of a combination of characters. Group one: long arms of chromosome I shorter than those of the longest chromosomes, long arms of chromosome II longer than those of the third pair, and arm ratios in chromosome II of 1.4–1.6. Group two: long arms of chromosome I longer than those of all others, long arms of chromosome II shorter than any of the others, arm ratios in chromosome II < 1:1.4. Species in the first group areAnemone canadensis, 2n = 14;A. richardsonii, 2n = 14; andA. fasciculata, 2n = 14; and in the second group,Hepatica americana, 2n = 14; andH. acutiloba, 2n = 14.Anemone multifidaandA. quinquefoliaare recognized as allotetraploids. The cytological results are discussed in relation to current classification.

ISSN:0008-4026    

DOI:10.1139/b59-049

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Young roots ofEuphorbia esulaexhibit a structure similar to that of a typical dicotyledonous species. In older roots, wood comprises as much as two-thirds of the total tissues. Cork is several layers thick, and lenticels are of open type. Pericyclic meristem forms a continuous ring any part of which may give rise to lateral organs. The primordia of lateral roots and shoots cannot be distinguished morphologically from each other until they have emerged from the parent organ. In the case of stems the lateral buds originate endogenously from the internodes but exogenously at the nodes. The subterranean organs of the species are supplied with simple, nonarticulated, and branched laticifers. Almost all parenchyma cells including the laticifers are filled with starch grains. The significance of these anatomical features with respect to the control of the species is discussed.

ISSN:0008-4026    

DOI:10.1139/b59-050

出版商:NRC Research Press    

年代:1959

数据来源: NRC