摘要:

Species ofCalvatiawere collected as part of a study of the higher fungi from arctic and alpine tundra in Alaska. Investigations revealed that manyCalvatiaspecimens did not possess the combination of characters described for previously reported taxa. Therefore, a study of the known taxa, including the holotypes, was initiated and the characteristics of these specimens were compared with those that we collected. The developmental morphology of sporocarps from a variety of habitats was studied. Scanning and transmission electron micrographs of the maturing spores were examined. Stages of maturation and variable weather conditions produced changes in the basidiospores and in the appearance of the exoperidium of the sporocarp. The dextrinoid reaction of the endoperidium inCalvatiais described for the first time. It is concluded thatCalvatia arcticaFerd. & Winge,C. borealisTh. C. E. Fries,C. tatrensisHollós, andC. tatrensisvar.groenlandicaM. Lange are conspecific withC. cretacea(Berk.) Lloyd, the onlyCalvatiaspecies known from the tundra.Calvatia tatrensisvar.gruberiA. H. Smith is reported as conspecific withC. bovista(Pers.) Kambly & Lee.

ISSN:0008-4026    

DOI:10.1139/b80-295

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

The mycelial growth ofCeratocystis ips, C. capillifera, C. piceae, andC. ulmiis inhibited by capric acid, and the fungitoxic effect of saturated acids decreases with the length of even numbered carbon chains (C 12:00, C20:0). Palmitic acid does not interfere with glucose for mycelial growth. A competition for the utilization of carbon sources seems to occur when both glucose and linoleic or linolenic acid are present in the medium. In all cases, oleic, linoleic, and linolenic acids are good carbon sources and trigger the differentiation of several fruit bodies.

ISSN:0008-4026    

DOI:10.1139/b80-296

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

In some areas of Iran, root rot of irrigated lentils (Lens culinaris) was a serious problem resulting in high plant mortality and decreased yields.Pythium ultimumwas the predominant soil-borne pathogen isolated from discolored, necrotic roots of diseased plants in furrow-irrigated fields at Karaj, and appeared to be the primary incitant of root rot of irrigated lentils at several other locations in the country.Pythium aphanidermatumwas the primary pathogen isolated from roots of diseased lentils at two irrigated sites in southern Iran. Isolates ofP. ultimumandP. aphanidermatumwere highly pathogenic on roots of lentil in greenhouse inoculation studies. Other fungi isolated from diseased lentil roots less frequently wereRhizoctonia solani, Phytophthorasp.,Macrophomina phaseolina, Fusarium oxysporum, F. roseum, andF. solani. Cultures ofR. solani, Phytophthorasp., andM. phaseolinawere less pathogenic on lentil roots than eitherPythiumsp., whereas the threeFusariumspp. were nonpathogens. Incidence and severity of root rot increased in Karaj field trials in treatments receiving N and P fertilizer and irrigation every 6 days. In greenhouse tests, incidence of root rot increased when naturally infested Karaj soils were amended with 1 or 10% cow manure before planting. Sources of resistance to the lentil root rot complex were found in germplasm screened in naturally infested soils at Karaj.

ISSN:0008-4026    

DOI:10.1139/b80-297

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

The thallus of the fungusEctrogella perforansPetersen inside its host, the diatomLicmophora hyalinaAgardh, is surrounded initially by two electron-dense membranes, of which the outer one is the invaginated host plasma membrane and the inner one, the fungal plasma membrane. Later, new membranes are added between these two membranes and the fungal envelope consists of four to six membranes. When the fungal thallus is mature, all the membranes except the fungal plasmalemma break down and it secretes an amorphous wall around itself. This coincides with the breakdown of host organelles followed by death of the host cell. Zoosporogenesis begins after the sporangium becomes multinucleate. A peculiar "multitubular body" is always observed in the multinucleate sporangium. A typical feature of the multinucleate sporangium prior to zoosporogenesis is the presence of a ring of tubular cisternae around the nuclei, electron-dense vesicles, and granular vesicles.The tubular cisternae found around the nuclei move away and act as cleavage cisternae. The cleavage cisternae run perpendicular to the sporangial plasma membrane and delimit the sporangial mass into uninucleate units at the time of zoosporogenesis. Simultaneously, vesicles are pinched off from the Golgi body which act as cleavage vesicles. These cleavage vesicles fuse with each other and form cleavage furrows. The cleavage cisternae fuse with the plasma membrane outside and with the cleavage vesicles inside and thus deepen the cleavage furrows. The sporangial mass is thus divided into zoospore units and the units are connected only by narrow cytoplasmic bridges. The zoospores have their flagella developed already. The structure of primary zoospores, encysted primary zoospores, and encysted secondary zoospores is described here.

ISSN:0008-4026    

DOI:10.1139/b80-298

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Septorin is a phytotoxin produced bySeptoria nodorum. It reduces the growth of susceptible wheat cultivar "Etoile de choisy" seedlings. On mitochondria isolated from the same cultivar, the septorin induces changes in respiratory activities similar to the 2,4 dinitrophenol (2,4 D) effects. In this paper, the conditions of "in vitro" production of septorin and the steps of the purification are described.

ISSN:0008-4026    

DOI:10.1139/b80-299

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Young, axenically grown roots of grasses are covered by two types of mucilage. Gelatinous material originates from the root cap, and a firm, uniformly thick mucilage overlies the columnar epidermal cells. Histochemical properties of these mucilages are similar in corn, wheat, barley, oats, sorghum, and a Sudan grass – sorghum hybrid.The epidermal mucilage has a thin outer and a thicker inner layer distinct from the epidermal cell wall. Both mucilage layers are strongly autofluorescent, birefringent, and PAS positive. Reactions of the outer layer and cell wall indicate carboxyl groups. These are absent from the inner mucilage. Root cap mucilage has a inner region with histochemical properties resembling those of the inner epidermal mucilage. The outer portion of the root cap mucilage is not fluorescent, not birefringent, weakly PAS positive, and carboxylated.

ISSN:0008-4026    

DOI:10.1139/b80-300

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Intact 6-day old soybean hypocotyls (Glycine maxL., cv. Altona) were inoculated with zoospores ofPhytophthora megaspermaDrechs. var.sojaeHildeb. either at the top (susceptible to compatible races, resistant to incompatible races) or the bottom (resistant to both compatible and incompatible races) and, after a 22-h incubation, were examined by light microscopy. Penetration at the top and bottom by both compatible (race 6) and incompatible (race 4)P. megaspermavar.sojaewas predominantly between anticlinal walls of epidermal cells. Both races, but especially race 4, also penetrated directly into the outer walls of epidermal cells, but epidermal cells rarely were invaded. Both races grew mainly intercellularly, but race 6 produced haustoria more frequently than race 4. Race 6 haustoria at the top of the hypocotyl were usually encased, those of race 4 were not. Growth of both races was equally dense in the first few cell layers, but the numbers of race 4 hyphae decreased rapidly while those of race 6 became more abundant in the deeper layers. With race 4, but not with race 6, most cells in the infected tissue were necrotic. Differences between the compatible and the incompatible interactions were not absolute; there were many unsuccessful invasion attempts by race 6 and individual hyphae of race 4 spread deeply into the tissue. At the bottom of the hypocotyl, growth of both races was more restricted. Race 6 produced fewer haustoria than at the top, and similarities to the incompatible reaction with race 4 at the top suggest that similar mechanisms of resistance may be involved.

ISSN:0008-4026    

DOI:10.1139/b80-301

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

During an extensive investigation of the composition of epicuticular waxes from members of the tribe Triticeae, 174 specimens of 123 species from 22 genera have been analyzed. Alcohol content and chain length, β-diketone, hydroxy-β-diketone, and oxo-β-diketone content and structure, and hydrocarbon and ester content have been determined. Sixteen characters have been derived from the results and examined by principal-coordinate and cluster analyses. The results showed considerable uniformity within the tribe; either alcohols, principally hexacosanol or octacosanol, or β -diketones were the major constituents of the wax, hydrocarbons and esters were always minor constituents. When genera were compared,Aegilops, Hordeum, andRoegneriawere found to be more uniform thanAgropyron, Elymus, Elytrigia, andLeymusbut distinctive differences between most of the major genera were observed.

ISSN:0008-4026    

DOI:10.1139/b80-302

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Branch tip death, leaf chlorosis and necrosis, leaf size, and leaf chloride content were measured in samples of aspen (Populus tremuloidesMichx.) collected from stands around nine potash mine–refinery complexes in Saskatchewan. Branch tip death and leaf chloride content were highest in stands near the mines. The proportion of injured leaves and variance in leaf size were highest in the region of maximum branch damage close to the mines. Most damage was confined to areas extending up to 6 km northwest and southeast of the mines and up to 3 km northeast and southwest. This pattern was related to prevailing wind directions. Variability in injury probably results from variation in salt dust emissions, meteorological conditions, and plant susceptibility. Branch tip death is the best indicator of injury from airborne salt.

ISSN:0008-4026    

DOI:10.1139/b80-303

出版商:NRC Research Press    

年代:1980

数据来源: NRC