摘要:

The study includes five bogs and one small lake. Preferred kettletype bogs were located very effectively by plane. The deepest section of the kettle lake was determined with a Bendix Depth Finder. The initial tree invaders in the whole park were chiefly jack pine (Pinus banksiana), paper birch (Betula papyrifera), a minor representation of spruce–fir (Picea–Abies), and oak (Quercus) characterized by an attention-demanding minor peak. After one or two foot-levels spruce–fir increased to considerable prominence, then declined to negligible representation in all bogs and in the lake by mid-profile. The pine peak at about mid-profile was uniformly very prominent over the whole area. In the topmost one-third to one-fifth of the profiles, pine declined steadily. The small representation of pine at topmost levels pictures very well its status in the region today. Mont Tremblant Park is a forest transition zone. In the range of 50 miles from Lac Puant bog to Lac Tacoma bog, abundance of spruce and fir pollens (especially that of black spruce) increase markedly as one proceeds northward. Pollens of beech (Fagus), oak, maple (Acer), and especially hemlock (Tsuga) and yellow birch (Betula lutea) show marked decrease northward. In the southern half of the transect hemlock is represented in the profiles by a decided pine–hemlock peak. Paper birch has erratic fluctuations in its prominent representation over the whole profile. From the forest type indicated at lowest levels we must infer an initial warm period. This is attributed to ocean invasion of the St. Lawrence Valley and slow retreat of continental glaciers. The combination of these factors delayed the forest invasion of the Canadian Shield until the boreal spruce–fir period, so characteristic of lowest levels in bogs farther south, had passed. Slight deterioration of climate thereafter with development of local glaciers on the Shield apparently accounts for the first minor rise of spruce and fir. A warm–dry period at mid-profiles is indicated by the universal prominent pine peak accompanied by extreme decline of spruce and fir. The succeeding increase in hemlock and white–red pine (later replaced by minor peaks of beech–maple) suggests a monster climate with increasing coolness. Continued cooling during more recent times in turn favored spruce, fir, and yellow birch. Pine, hemlock, beech, and oak declined to a status of minor elements in the forest association. The erratic fluctuations of paper birch and its abundance at all levels show little correlation with major climatic changes.

ISSN:0008-4026    

DOI:10.1139/b54-053

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

Dwarf kidney beans and tomatoes were grown in complete nutrient solutions containing various concentrations of iron and manganese. It was found that the iron to manganese ratio in the culture solutions must be within a definite range in order to avoid deficiency symptoms in the experimental plants. For the dwarf bean this range was 1.5 to 3.0, and for the tomato it was 0.5 to 5.0. Concentration ratios outside the optimum range produced either iron or manganese deficiency symptoms. Concentrations below minimum values of both iron and manganese always produced deficiency symptoms irrespective of the ratio of iron to manganese in the culture solutions. An apparent antagonism between the absorption of iron and of manganese was observed with both beans and tomatoes grown in nutrient solutions. This antagonism was also found to occur with onions grown in solutions containing only the sulphates of the two metals. It was further found that with onions growing in single salt solutions of the sulphates of iron and manganese, the concentration of iron or manganese in the solutions did not affect the amounts of the metals absorbed by the plants from the solutions. The combined amount of iron plus manganese absorbed appeared to remain constant irrespective of the iron to manganese ratio in the culture solution.

ISSN:0008-4026    

DOI:10.1139/b54-054

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

The amino acids present in roots of healthy and diseased (Helminthosporium sativumP. K. & B.) wheat seedlings were determined by paper chromatography. Treatment of dried roots with 80% ethanol followed by acid hydrolysis effected maximum extraction of the amino acids. Eleven free and 13 combined amino acids were identified on the chromatograms, and four unidentified fractions were indicated. Total nitrogen of the diseased roots was higher on a dry weight basis than that of healthy roots. The aggregate content of both free and combined amino acids was slightly higher in the diseased roots than in the healthy ones. However, the concentrations of free alanine, serine, and asparagine in the diseased roots were twice those in the healthy ones.

ISSN:0008-4026    

DOI:10.1139/b54-055

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

A taxonomic study was made of isolates ofFusariumobtained from a microbiological examination of seed from a total of 44 species and botanical varieties of cultivated plants. These plants may be classed as vegetable, forage, and miscellaneous crops. Most of the seed samples originated from stocks produced in Canada, but some were seed from other countries. A total of 16 species, varieties, and forms ofFusarium, classified in eight sections of the genus, were encountered among the isolates that were obtained from seed; they areF.poae(Pk.) Wr.,F.sporotrichioidesSherb.,F.arthrosporioidesSherb.,F.avenaceum(Fr.) Sacc,F.semitectumBerk. & Rav.,F.acuminatumEll. & Ev.,F.compactum(Wr.) Gordon,F.equiseti(Cda.) Sacc,F.culmorum(W. G. Sm.) Sacc,F.graminearumSchwabe,F.sambucinumFuckel,F.sambucinumvar.coeruleumWr.,F.moniliformeSheld. em. S.&H.,F.oxysporumSchlecht. em. S. & H.,F.oxysporumf.lini(Bolley) S. & H.,F.solani(Mart.) App. & Wr. em. S. & H. From the seed of a total of 44 species and botanical varieties of host plants,F.equisetiwas identified among isolates from 34;F.poaeandF.oxysporumeach from 18;F.acuminatumfrom 17;F.avenaceumfrom 16;F.culmorum, from 10;F.sambucinumandF.moniliformeeach from five;F.graminearumandF.sambucinumvar.coeruleumeach from four;F.solanifrom three;F.sporotrichioidesfrom two;F.arthrosporioides,F.semitectum,F.compactum, andF.oxysporumf.linieach from one. The origin of the seed samples of each host is given.

ISSN:0008-4026    

DOI:10.1139/b54-056

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

The numbers of bacteria and fungi in air masses over Montreal, Canada, were determined by sampling at the top of the Sun Life Building, 400 ft. above ground level, from September 1950 to December 1951. During 113 days of sampling, 978 exposures were made with agar plates in the General Electric Bacterial Air Sampler and the Bourdillon Slit Sampler. Eighty-seven exposures for fungus spores were made with silicone coated slides in the Slit Sampler. Most of the air encountered was continental polar either moving direct to Montreal, found on 38 days, or modified by moving over agricultural land, sampled on 51 days. Maritime polar air from the Atlantic was encountered on 21 days, and from the Pacific on one day. Maritime tropic air from the Gulf of Mexico was encountered twice. The seasonal variation of bacteria and fungi in all air masses showed low counts in January, February, and March. Higher bacterial counts were obtained from early April into July and from early September into November, covering a range from 3.0 to 55.0 per cu. ft. Lower counts were found during late July and August. The high fungus counts extended from May into November and covered a range from 5.0 to 56.3 per cu. ft. Both continental polar and maritime polar air that moved over considerable cultivated land showed generally higher counts than where these air masses moved directly to Montreal.

ISSN:0008-4026    

DOI:10.1139/b54-057

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

Fifty-six recently discovered spores and sporelike microfossils from Canadian non-coaly deposits of Middle and Upper Devonian age are described and classified. Their manner of occurrence suggests their probable usefulness in the establishment of biostratigraphic entities, and their applicability to the stratigraphic study of oil-bearing rocks. Relative to the history of plants, the microfossils convey evidence of a. more complex and more highly evolved Devonian flora than has been apparent from the macrofossil record. In addition, preliminary examination has disclosed spores of comparable abundance and of only slightly less complexity in rocks of Lower Devonian and Silurian age.

ISSN:0008-4026    

DOI:10.1139/b54-058

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

A taxonomic study was made of 12,485 isolates ofFusariumthat were obtained from a total of 1674 soil samples taken from two series of permanent cereal plots during the years 1936–1942. Isolates ofFusariumaveraged approximately 16% of total fungus isolates. A total of 16 species, varieties, and forms ofFusarium, classified in eight sections of the genus, were isolated. These species, varieties, and forms areF.dimerumPenz.,F.merismoidesCda.,F.poae(Pk.) Wr.,F.sporotrichioidesSherb.,F.avenaceum(Fr.) Sacc.,F.concolorRg.,F.semitectumBerk. & Rav.,F.acuminatumEll. & Ev.,F.equiseti(Cda.) Sacc.,F.culmorum(W. G. Sm.) Sacc.,F.sambucinumvar.coeruleumWr.,F.sambucinumf. 6 Wr.,F.oxysporumSchlecht, em. Snyder & Hansen,F.oxysporumvar.redolens(Wr.) Gordon,F.solani(Mart.) App. & Wr. em. Snyder & Hansen. The majority of the species isolated were encountered each year.F.oxysporumandF.equiseti, together, accounted for approximately 75% of the totalFusariumisolates. Average concentrations per gram of soil of these two species were approximately 4800 and 2300 'units', respectively. Average concentrations per gram of soil of each of the remaining species isolated were below 600 units. Except forF.dimerumandF.merismoides, the species, varieties, and forms that were obtained from soil have been isolated previously from the basal parts and seed of cereals in the Prairie Provinces.

ISSN:0008-4026    

DOI:10.1139/b54-059

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

An investigation of Douglas fir,Pseudotsuga taxifolia(Poir.) Britton, in coastal British Columbia has shown that decay losses in old-growth stands are low, amounting to 2.6 and 7.3% of the gross volume of living and combined living and dead trees respectively. Twenty-five decay-producing fungi were isolated from living trees and 29 from dead trees. The most important of these wereFomes pini(Thore) Lloyd,Polyporus schweinitziiFries, andFomes pinicola(Sw.) Cke. Certain irregularities in the occurrence of decay-producing fungi and the amounts of decay associated with them were traced to the influences of site, tree age or size, latitude, and stand history. Root infections were the most frequent but branch-stub infections caused the greatest average amount of decay. An examination of tree abnormalities showed that a select group of them, sporophores and swollen knots ofFomes piniin particular, are useful indicators of hidden decay. A separate analysis of dead trees has shown that they occasion ally form a high proportion of Douglas fir stands and that much of the wood in such trees is sound.

ISSN:0008-4026    

DOI:10.1139/b54-060

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

This study of blackberries deals with seed production and germination, describes the main steps in megagametophyte development of pseudogamous and syngamous varieties, and traces the development of both germinable and aborted seeds. Certain conclusions are drawn concerning the interdependence of maternal and filial tissues. The number of drupelets which develop in both pseudogamous and syngamous varieties depends, in part, on the pollen parent. A small but rather constant proportion of the drupelets display only a partial enlargement. Seeds of the well-developed drupelets are divided into three intergrading classes: (i) plump seeds, (ii) collapsed seeds, and (iii) an intermediate group. The general developmental features of the ovule and its contents are described. Regular megagametophyte formation is the rule in the syngamous varieties, but many irregularities, especially multiple gametophytes, are common in the pseudogamous species studied. Approximately a third of the seeds in the drupelets which appeared normal at 6 to 15 days after pollination did not contain an embryo. Some of the "eggs" were disintegrating, whereas others were still in a turgid condition. All the seeds which were imperfectly developed contained endosperm but only rarely was there an embryo or its remains. Reserve food was usually stored only in the chalazal region of the endosperm. The endosperm is believed to stimulate the transfer of nutrient materials to the seed. The embryo supplements this function as the seed approaches maturity, and influences the distribution of the storage products within the endosperm.

ISSN:0008-4026    

DOI:10.1139/b54-061

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

Of 51 dried soil cultures of fungi isolated from soil, only 12, comprising seven of the 32 genera represented, were viable after five years. Platings, directly from the cultures, of 5-, 50-, and 500-mgm. samples with oxgall-amended potato dextrose agar revealed extreme variations in viability of surviving fungi. Population levels were so high in cultures ofRhizopus nigricans,Aspergillus fumigatus,A.sydowi, andA.ustusthat plate counts were not obtained, even when a 5-mgm. sample was apportioned among five plates. Cultures ofChaetomium indicumand ofC.spiralecontained an estimated population of approximately one and one half million, and 450,000 viable centers per gram, respectively, the highest counts obtained. The next most viable cultures were those ofFusarium oxysporumvar.redolensand ofCircinella spinosa, but these contained only about 60,000 and 20,000 centers per gram, respectively. Next camePenicillium janthinellumwith an estimated 4000 centers per gram. The least viable cultures were those ofPenicillium purpurogenumand of two isolates ofF.oxysporumwhose population level was down to about 100 to 200 viable centers per gram.

ISSN:0008-4026    

DOI:10.1139/b54-062

出版商:NRC Research Press    

年代:1954

数据来源: NRC