摘要:

Examination of 835 living trembling aspen (Populus tremuloidesMichx.) and 527 balsam poplar (Populus balsamiferaL.) on 47 sample plots of mixed-wood forest of the Boreal Forest Region, Alberta, showed 73% of the aspen and 61% of the balsam poplar to be decayed. Additional trees of both species were infected by stain-producing fungi. The incidence of infection in aspen decreased from mesic sites to dry sites, while that for balsam poplar was about the same in mesic and wet sites.Fomes igniarius(L. ex Fr.) Kickx was the first ranking fungus in both hosts in terms of associated decay. It had the greatest incidence of all fungi in aspen but ranked third toPholiota spectabilis(Fr.) Quél. andPolyporus aduslusWilld. ex Fr. in balsam poplar.Corticium polygoniumPers. andRadulum casearium(Morg.) Lloyd together caused about as much decay in aspen as didFomes igniarius, although neither fungus occurred in balsam poplar. Contrary to its generally low incidence in balsam poplar,Pholiota destruens(Brond.) Quél. caused most of the decay in this host, excepting that ascribed toFomes igniarius.Pholiola destruensdid not occur in aspen. Many fungi caused both basal and stem infections in both hosts, while few caused infections of one type only.Armillaria mellea(Vahl ex Fr.) Quél. caused the greatest number of basal infections in aspen but was exceeded byPholiota spectabilisin balsam poplar. The greatest amount of butt decay was ascribed toPhlebia strigosozonala(Schw.) Lloyd in aspen and toPholiota spectabilisin balsam poplar. The overall losses of volume due to decay were 25% and 10%, respectively, for aspen and balsam poplar.

ISSN:0008-4026    

DOI:10.1139/b60-042

出版商:NRC Research Press    

年代:1960

数据来源: NRC

摘要:

The effect of metabolites and antimetabolites on rust development was studied, using detached leaves of Little Club wheat floated on solutions containing benzimidazole plus the compound under study. Purines and pyrimidines, vitamins, amino acids, carbohydrates, and enzyme poisons were tested. A number of these compounds inhibited leaf and stem rusts of wheat at concentrations that were not injurious to the host. Of the purines and pyrimidines that were tested, thymine and the analogue azathymine were the only effective inhibitors. The antivitamin oxythiamine was inhibitory and the inhibition was competitively reversed by thiamine.A few natural amino acids, notably histidine, isoleucine, methionine, and serine, inhibited rust development. The inhibition was reversed by glycine in all cases except with serine. Amino acid analogues, particularly canavanine, ethionine, andp-fluorophenylalanine, were excellent inhibitors; the inhibitions were reversed by comparable levels of arginine, methionine, and phenylalanine respectively. The carbohydrates lyxose, xylose, sorbose, and all the sugar alcohols tested were effective inhibitors of rust development. Of the enzyme poisons tested, sodium fluoride and sodium azide differentially inhibited rust growth.

ISSN:0008-4026    

DOI:10.1139/b60-043

出版商:NRC Research Press    

年代:1960

数据来源: NRC

摘要:

Analyses for sulphate, calcium, and pH have been made on surface waters from 102 lakes and ponds in the Sudbury metal-smelting district, and data are presented for 35 of these. Sulphur pollution is frequently high within about 5 miles of the three smelters, many ponds exhibiting more than three times the sulphate concentration normal for this area, and three waters more than 10 times this level. Outside about 15 miles distance the influence of smelter pollution upon sulphate concentrations in surface waters is negligible. As expected, many of the most polluted waters are strongly acid, with pH values going as low as 3.3. Sulphuric acid from air pollution has also led to increased weathering of calcium from soils and rocks, so that this ion tends to rise in concentration not only in waters above pH 6 (as expected) but also in those below pH 5.Damage to terrestrial vegetation is frequently marked within about 5 miles of the smelters, while it is seldom obvious to the untrained eye beyond this distance. Severe damage occurs chiefly within about 2 miles of the smelters.

ISSN:0008-4026    

DOI:10.1139/b60-044

出版商:NRC Research Press    

年代:1960

数据来源: NRC

摘要:

Leaf disks ofPelargoniumwere shown to be capable of synthesizing phlorin-C14when administered phloroglucinol together with C14-labelled glucose, sucrose, or succinic acid. Changes with time in the distribution of radioactivity in phlorin and in sucrose in disks maintained on phloroglucinol and glucose-C14, in the light or in the dark, were followed. Phlorin-C14synthesis predominated in the dark and sucrose-C14synthesis in the light. The steady accumulation of phlorin with time suggests that it is not utilized metabolically. Labelled phlorin and sucrose were formed when succinate-1,4-C14or succinate-2,3-C14was administered in the light. Labelled hexoses were obtained with succinate-2,3-C14in the dark. Possible pathways for the conversion of succinate to sugars are suggested. In these experiments the synthesis of sucrose-C14from succinate-C14was reduced in the presence of phloroglucinol, concomitant with the formation of phlorin-C14.

ISSN:0008-4026    

DOI:10.1139/b60-045

出版商:NRC Research Press    

年代:1960

数据来源: NRC

摘要:

The seeds of 161 species of legumes, representing 78 genera, were examined by chromatographic methods for canavanine content. The results are supplemented by data, variously collected, by other authors, to yield a total of 219 investigated species representing 109 genera. Of these, 68 species belonging to 32 genera have canavanine in their seeds.Canavanine has not been found in the subfamilies Mimosoideae or Caesalpinioideae. In the subfamily Papilionoideae it has not been found in the tribes Podalyrieae and Sophoreae. At least one species from each of the other tribes produces canavanine. In three genera, some species produce canavanine while others do not.These data are presumed to be of taxonomic significance and have been interpreted as support for chromosomal information indicating that the tribes Mimosoideae and Caesalpinioideae diverged relatively early from the "stem" line which is now represented by the Papilionoideae.

ISSN:0008-4026    

DOI:10.1139/b60-046

出版商:NRC Research Press    

年代:1960

数据来源: NRC

摘要:

In red clover only one ovule of the two in each ovary regularly develops into a seed. Results of two experiments designed to reveal the fate of the ovules initially present provide a basis for comparing some features of ovule development in high- and low-seed-yielding plants. High-yielding plants produced embryo sacs in over 70% of ovules whereas low-yielding ones produced them in about 40%. The ability to produce embryo sacs seems to be genetically determined but strongly influenced by environment and occasionally by meiotic irregularities. Development started in about 85% of the fertile ovules in the high-yielding plants but in only about 60% of them in low-yielding plants. Apparently there was slow or limited growth of pollen tubes in the latter plants. Nearly 55% of the ovules developing just after fertilization matured into seeds in the high-yielding plants but only about 25% in the low ones. The higher frequency of ovule collapse in low-yielding plants seems to be a consequence of the delayed fertilization followed by retarded growth of the embryos and endosperms.Although a few more ovules did start to develop in out-crosses than in sib-crosses, the more vigorous growth of the endosperm seems quite important in accounting for the superior seed yields in the out-crosses. Also a few more ovules started to develop when the pollen came from a high-yielding plant instead of a low-yielding one and this initial advantage seems to lead to improved seed production.It is suggested that low-seed-producing plants may have certain genes that act like weak self-incompatibility alleles by inhibiting pollen tube growth, or, that their genetic constitutions are such that they cannot produce enough embryo sacs and/or support the growth of pollen tubes and ovules.

ISSN:0008-4026    

DOI:10.1139/b60-047

出版商:NRC Research Press    

年代:1960

数据来源: NRC

摘要:

The population and viability of spores ofHelminthosporium sativumfrom two locations in each of 100 cultivated fields in Saskatchewan were determined in the spring of 1959. The determinations were made by the flotation–viability count method as described herein. Spore numbers in the different samples ranged from a count of less than 8 to 893 with an average of 118 per gram of soil. A predominant number of the samples contained 200 or less spores per gram. Soils summerfallowed or cropped to cereals in 1958 did not differ significantly in spore populations. The coefficient of correlation between the populations of the paired samples in the fields was 0.83. Viability of spores varied from 11 to 100%; a relatively small number of the samples was in the 11 to 30%, and the others were fairly evenly distributed in the 31 to 100% range. Evidence is presented to support the reliability of the flotation–viability count method. The applicability of the method to studies of various root rot problems and the behavior of certain fungi, other thanH. sativum, in soil is discussed.

ISSN:0008-4026    

DOI:10.1139/b60-048

出版商:NRC Research Press    

年代:1960

数据来源: NRC

摘要:

Chromosome numbers and voucher specimens are recorded for some collections of 25 genera of grasses, mainly collected in Canada. The somatic chromosome numbers of the following are recorded: (1)Agrostis borealis, 2n = 56;A. canina, 2n = 14;A. gigantea, 2n = 42;A. palustris, 2n = 30;A. perennans, 2n = 42;A. scabra, 2n = 42; andA. tenuis, 2n = 28; 32; and 34. (2)Alopecurus acqualis, 2n = 14;A. alpinus, 2n = 105; 112; and 119;A. geniculatus, 2n = 28;A. occidentalis, 2n = 112; andA. pratensis, 2n = 28. (3)Ammophila breviligulata, 2n = 28. (4)Anthoxanthum odoratum, 2n = 20. (5)Calamagrostis canadensis, 2n = 42; and 56;C. inexpansa, 2n = 70;C. lapponica, 2n = 28; 32; 42; ca. 91; 98; and 140;C. neglecta, 2n = 28;C. pickeringii, 2n = 28;C. purpurascens, 2n = 28; 42; and 84; andCalamagrostissp.?, putative hybrid, 2n = 49. (6)Cinna arundinacea, 2n = 28; andCinna latifolia, 2n = 28. (7)Danlhonia compressa, 2n = 36; andD.spicata, 2n = 36. (8)Deschampsia brevifolia, 2n = 26;D. caespitosa, 2n = 26; 27; and 28;D. elongata, 2n = 26;D. flexuosa, 2n = 28; and 32; andD. pumila, 2n = ca. 39. (9)Hierochloë alpina, 2n = 56; andH. odorata, 2n = 56. (10)Koeleria cristata, 2n = 14. (11)Leersia virginica, 2n = ca. 48. (12)Milium effusum, 2n = 28. (13)Muhlenbergia squarrosa, 2n = 40; andM. uniflora, 2n = ca. 42. (14)Nardus stricta, 2n = 30. (15)Oryzopsis asperifolia, 2n = 48;O. pungens, 2n = 24; andO. racemosa, 2n = 48. (16)Panicum xanthophysum, 2n = 36. (17)Phalaris arundinacea, 2n = 28. (18)Phleum alpinum, 2n = 28; andPhleum pratense, 2n = 42. (19)Sieglingia decumbens, 2n = 36. (20)Sorghastrum nutans, 2n = 40. (21)Spartina gracilis, 2n = 42. (22)Sphenopholis intermedia, 2n = 14. (23)Sporobolus cryptandrus, 2n = 36. (24)Stipa comata, 2n = 44. (25)Trisetum flavescens, 2n = 28;T. molle, 2n = 42; andT. spicalum, 2n = 28.

ISSN:0008-4026    

DOI:10.1139/b60-049

出版商:NRC Research Press    

年代:1960

数据来源: NRC

摘要:

Heterochaetellais retained as a separate genus to include three species.Heterochaete dubiaBourd. & Galz. is the type.Heterochaetella bispora, found on decayed wood in Ontario, is proposed as a new species.Heterochaetella brachyspora, treated as a variety ofH.dubiaby Bourdot and Galzin, is raised to specific rank. A redescription of the genus is given as well as descriptions and illustrations of the three species.Heterochaetella crystallinaBourd. is considered a synonym ofStypella papillataMöller and not congeneric withH.dubia.

ISSN:0008-4026    

DOI:10.1139/b60-050

出版商:NRC Research Press    

年代:1960

数据来源: NRC

摘要:

The present palynological study is used as a new approach to determine the stratigraphical and chronological position of the Pleistocene interglacial deposits, the Toronto formation, exposed in sections at Toronto, Ontario, Canada.An interpretation of lithology, combined with evidence supplied by the pollen and spore assemblages, indicates that the Don beds, the lower member of the Toronto formation, belong to the Sangamon Interglacial. The Scarborough beds, the upper member of the formation, were deposited during a nonglacial interval, cooler than the present. Conformity between the two members is questioned on grounds of lithological and palynological evidence.Results of palynological studies, as indicated by this investigation, can be used for interpretation of the mode of deposition of certain laminated sediments and for reconstruction of past types of landscape.

ISSN:0008-4026    

DOI:10.1139/b60-051

出版商:NRC Research Press    

年代:1960

数据来源: NRC