摘要:

Humicola dimorpliosporais described as a new species. It is pleomorphic, producing dark, thick-walled, holoblastic conidia from portions of the vegetative hyphae as the principal spore type and hyaline, thin-walled, holoblastic conidia from sympodially proliferating conidiogenous cells as the secondary. The secondary spore type is characteristic of the genusSporothrix. The type culture, ATCC 22422, was isolated from Saskatchewan soil, Canada, and is being preserved by freeze-drying and by storage in liquid nitrogen at – 196C. The range of temperature for growth of the fungus is 10 to 30C.

ISSN:0008-4026    

DOI:10.1139/b74-066

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Hormones produced by haploid cells of one mating type ofT. mesentericaand inducing conjugation tubes in the other mating type have been studied in preparation for isolation and identification. The active material can be extracted from aqueous solution withn-butanol, but not with less polar solvents, and is adsorbed on cation and anion exchange resins, charcoal, and neutral polystyrene resin. The molecular weight is probably less than 1000. Three active components can be separated by silica gel column chromatography with a gradient of water in ethanol, or by paper chromatography. The conjugation hormones may be non-polar amino acids or small peptides.

ISSN:0008-4026    

DOI:10.1139/b74-067

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

The responses of 14 weed species to seven different herbicides were compared. The species included five monocots:Agropyron repens(L.) Beauv.,Agrostis albaL.,Carex gracilescensMack.,Phleum pratenseL., andPoa pratensisL.; and nine dicots:Ambrosia artemisiifoliaL.,Aster cordifoliusL.,Fragaria virginianaDuchesne,Oxalis europaeaJord.,Pastinaca sativaL.,Solidago canadensisL.,S. nemoralisAit.,Taraxacum officinaleWeber, andVicia craccaL. A principal component analysis revealed that species responses to four auxin herbicides ((2,4-dichlorophenoxy)acetic acid (2,4-D), picloram, picloram + 2,4-D, and 2,4-D + (2,4,5-trichlorophenoxy)acetic acid (2,4,5-T)) were very similar, although picloram was more effective in eliminatingAster cordifolius, Fragaria virginiana, Solidago nemoralis, andVicia cracca. Auxin response differed markedly between monocots and dicots, whereas life-form was important in determining the response of the species to paraquat, simazine, and diuron treatments. Response to herbicide treatment was similar in both pioneer and mature old-field communities. However,Phleum pratenseandPoa pratensiswere susceptible to all auxin treatments in the pioneer community but were resistant to the same treatments in mature fields.

ISSN:0008-4026    

DOI:10.1139/b74-068

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Information about the effects of germination on cytoplasmic membranes of cotyledons has been obtained by examining selected properties of smooth microsomes purified from cotyledon tissue at various stages of germination. The microsomal membranes contained rotenone-insensitive NADH – cytochromecreductase (EC. 1.6.99.3) and NADPH – cytochromecreductase (EC. 1.6.99.1). Measurements of these enzymes in smooth microsomal fractions isolated from various ages of cotyledon tissue revealed that their activities markedly decrease during the late stages of germination, coincident with onset of cotyledon senescence. This decrease is closely paralleled by a corresponding decline in total levels of the enzymes in the cotyledons during the same period, and has been interpreted as reflecting deterioration of cytoplasmic membrane structure and function concurrent with the progression of senescence. The membrane-bound cytochromecreductase activity does not appear to be solubilized as a result of this deterioration. Furthermore, the protein:phospholipid ratios for the smooth microsomal preparations remain essentially unchanged during germination. This suggests that the macro-molecular complexes of membranes disaggregate more or less spontaneously during senescence and that in the process, the cytochromecreductases are inactivated.

ISSN:0008-4026    

DOI:10.1139/b74-069

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

The morphology, cytology, distribution, and phylogeny of eight species of the southwestern United States closely related toCirsium arizonicumare considered. These species form a natural group distinguished from other North American species ofCirsiumby a short stigma (1–3 mm) and long corolla lobes (10–20 mm) which are longer than the corolla throat. Three new species described areC. chellyense, C. chuskaense, andC. navajoense. Original chromosome counts are presented forC. nidulum, 2n = 34;C. rothrockii, 2n = 30;C. arizonicum, n = 15;C. chuskaense, 2n = 34; andC. arizonicum×nidulum, 2n = 32, 34.

ISSN:0008-4026    

DOI:10.1139/b74-070

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Lulworthia medusa, the marine isolate, grew significantly better in seawater than in freshwater medium. The growth ofOphiobolus graminis, the freshwater isolate, was reduced by one-half when grown in seawater. The growth of both species was similar in natural and artificial seawater. Neither species grew under anaerobic conditions.Warburg reactions indicate that the respiration of the freshwater species is reduced in seawater. The percentage reduction is about equal to the reduced growth in seawater, as compared to freshwater. The respirational rates ofL. medusain sea and freshwater were similar. Yet growth in seawater was much greater than in freshwater. Consequently, it is proposed that the respiratory energy produced in a freshwater environment is utilized for cellular functions other than biomass increase. In contrast to the marine isolate, the metabolic processes ofO. graminisare severely affected by seawater. Ecological implications of the findings are discussed.

ISSN:0008-4026    

DOI:10.1139/b74-071

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

The net CO2exchange responses ofC. carolinianain the fall to light, thallus temperature, and thallus relative water content were determined.Cladonia carolinianaresponses were compared with three northernCladonia: C. mitis, C. rangiferina, andC. uncialis. The eco-physiological characteristics of the four species provide some intuitive understanding of their biogeography and their microhabitat selection on the Wisconsin Pine Barrens. The temperature dependence of net photosynthesis of the four species correlates with their distributional relations.Cladonia carolinianais physiologically adapted to higher temperatures than the three northern species. The limitations of this intuitive comparison are discussed and a quantitative alternative suggested.

ISSN:0008-4026    

DOI:10.1139/b74-072

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Seeds from six individual plants ofRumex crispusL. were stored under four contrasting conditions of temperature and relative humidity for 6 mo to 5 years. After storage, all viable seeds germinated under conditions of diurnally alternating light and temperature but there were significant interplant differences in the number of seeds that germinated in continuous darkness at constant or alternating temperatures. Seeds stored at room temperature had less precise germination requirements than those stored under frozen or chilled conditions. Viability was retained for 5 years under all storage conditions except for samples from three parent plants stored under chilling temperatures and variable humidity where 10 to 60% of the seeds had died. Germination of seeds was more rapid after storage.This experiment demonstrated that variable storage conditions can have a distinct effect on the germination patterns of seeds ofR. crispus. Moreover, seeds from different plants responded in different ways to storage under the same conditions. Also, germination patterns under one germination regime were not predictable on the basis of results under another regime.

ISSN:0008-4026    

DOI:10.1139/b74-073

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

Two juvabione-related compounds, (+)-todomatuic acid and dehydrotodomatuic acid, were found in conjunction with certain balsam woolly aphid infestedAbies grandis(Dougl.) Lindl. andAbies amabilis(Dougl.) Forbes but not with noninfested trees.The localized occurrence and variable distribution of these compounds within the wood of infested trees is discussed.

ISSN:0008-4026    

DOI:10.1139/b74-074

出版商:NRC Research Press    

年代:1974

数据来源: NRC

摘要:

PodosordariaEllis et Holw. is used for those members of the Xylariaceae possessing stalkedor sessile stromata in the form of mammillate heads with erumpent ascocarps, containing whitish internal tissue, and covered with a brown to black or violaceous ectostroma; cylindrical to pyriform asci in which the ascospores may be biseriately arranged posteriorly; and one-celled, dark brown spores possessing elongated germ slits. The classical separation betweenPoroniaWilld. ex Fr. andPodosordariais maintained. An emended generic description and key are provided. Four new species and one new combination are described and illustrated—P. crinitaon cow dung from the United States;P. ianthinaon burro and goat dung from Mexico;P. phoeniceaon zebra dung from Kenya;P. vinaceaon burro dung from Mexico; andP. violacea(Sordaria violaceaEll. et Ev.) on cow, sheep, horse, and rabbit dung from Canada and the United States. One additional new combination,P. hircina(Poronia hircineTai et Wei), is proposed. Brief comparative descriptions are included for those species not treated in detail. Short descriptive notes are provided for several taxa considered as doubtful representatives.

ISSN:0008-4026    

DOI:10.1139/b74-075

出版商:NRC Research Press    

年代:1974

数据来源: NRC