摘要:

Sirococcusblight, caused bySirococcus strobilinusPreuss, was shown to be a seed-borne disease of container-grownPicea sitchensis(Bong.) Carr.,P.glauca(Moench) Voss,P.engelmanniiParry, andP.glauca×P.engelmanniispruces. The fungus was best detected by germinating seeds from seedlots with consistent disease histories, in autoclaved soil mix in pots (kept at 16 to 20 °C, and at light intensities of 900 to 1800 lx), and isolating the pathogen from diseased seedlings. Seed-borne isolates ofS.strobilinuswere pathogenic toP.sitchensisseedlings. The pathogen was present on 0.3 to 3.1% of the seeds of infested seedlots. Seeds with shrunken contents yielded the pathogen seven to nine times more often than seeds with normal-appearing contents. Disease incidence was unrelated to seedcoat damage or prevalence of empty seeds. Histological examinations revealed presence of the pathogen throughout the endosperm and embryo tissues of diseased seeds. The results are discussed in relation to incidence ofSirococcusblight in Coastal, container nurseries.

ISSN:0008-4026    

DOI:10.1139/b81-080

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

A critical study of the differentiating features of the North American populations ofTimmia sibiricaLindb.etArnell andT. norvegicaZett. reveals that populations with structure intermediate between these two taxa occur. Although from widespread localities, the intermediate specimens seem limited in number andT. sibiricaandT. norvegicaquite commnonly occur in mixed populations with no evidence of any intergradation. Therefore, it is concluded that the two taxa ought to be regarded as distinct species. The taxonomically important character-states of upper leaf cells and costa ofT. sibirica. T. norvegica, and of the intermediate populations are illustrated with scanning elecron micrographs. The habitat ofT. sibirica, like that ofT. norvegica, is invariably on strongly calcareous substrates adjacent to waterfalls, along streams, or in low-lying tundra. The North American distribution ofT. sibiricais mapped, including previously unreported localities as far south as 51° N in the Canadian Rocky Mountains.

ISSN:0008-4026    

DOI:10.1139/b81-081

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

One hundred and sixty-one accessions, from species which share a common genome with hexaploid wheat (Triticum aestivumE., ABD genome), were rated for cold hardiness following acclimation under fall field conditions. These accessions were from the speciesT. tauschii(Coss.) Schmal. (D genome);T. monococcum. L., andT. boeoticumBoiss. (A genome); andT. dicoccumShrank andT. dicoccoidesKorn. (AB genome). Accessions fromT. tauschiisurvived the coldest temperatures and had a hardiness level which approached the hardiest hexaploid wheats. The most hardy A genome accessions survived temperatures comparable to hexaploid wheats with low cold hardiness potentials. The remainder of the A and the AB genome wheats were relatively unhardy.

ISSN:0008-4026    

DOI:10.1139/b81-082

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Rarely collected Agaricales colonizing wetland monocotyledonae are illustrated and described from Canadian specimens. The occurrence ofGloiocephala menieri,Marasmius caricis,M.limosus,Marasmiellus vaillantii,Mycena bulbosa, andPholiota graminisin North America is documented. In addition, the first Canadian records ofMycena juncicolaand range extensions in Canada forPsathyrella typhaeandMycena stylobatesare given.Marasmius flavomerulinussp.nov. was found onScirpusin Quebec.

ISSN:0008-4026    

DOI:10.1139/b81-083

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

For three components (apical meristem, subapical internodes, and foliar apparatus) ofPisum sativum(cv. nain hâtif d'Annonay) cotyledonary buds, DNA microdensitometry, mitotic indices, and release of growth have been used to detect changes produced by kinetin applications (50 μg/mL). One kinetin treatment is sufficient to release the cell cycle, but continuous kinetin supply is necessary to maintain bud elongation. At the apical, subapical, and foliar levels, inhibited cotyledonary buds contain a majority of nuclei with 2C DNA content, in the G1phase of the cell cycle. Following hormonal treatment, the prereplicative phase of the noncycling cells is at least 6 h in the whole bud. The lag period for the release of bud growth is between 15 and 23 h in subapical regions (first and second internodes) and between 23 and 38 h at the foliar level. At subapical and foliar levels, a few mitoses precede and then follow the elongation process. The first mitoses are from G2nuclei of the inhibited bud. The following ones, more numerous, are from noncycling cells of inhibited buds, which have entered the S phase in response to kinetin application. The degree of inhibition of an axillary bud, estimated by the distribution of the DNA content in its three components, conditions the events induced by hormonal treatment or decapitation. The discussion shows how the knowledge of the original nuclear states of inhibited buds is necessary to understand axillary bud reactivation.

ISSN:0008-4026    

DOI:10.1139/b81-084

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

To study the phenological adaptation of the life history of ferns to colder regions, the freezing resistance of gametophytes and sporophytes of 14 cool temperate region ferns native to Hokkaido was evaluated in Sapporo. Moreover, drought tolerance of gametophytes of some cool temperate ferns was elucidated. The mature sporophytes were hardy from −5 to −20 °C in most species. However, gametophytes of most species were tolerant to below −40 °C and regrew into normal gametophytes in a month at room temperature. Most of the gametophytes survived well after dehydration to 2–10% water content. The gametophytic generation was more cold tolerant than the sporophytic one. Thus, the gametophytic generation, rather than the sporophytic, might be the generation that survives cold temperature in the field.

ISSN:0008-4026    

DOI:10.1139/b81-085

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Lipid in vesicles and hyphae reacted positively to a variety of reagents that have an affinity for neutral lipids. In contrast, arbuscules did not appear to contain neutral lipid, but did react positively to phosphoglyceride tests and glycolipid. Walls of vesicles and hyphae contained chitin, but arbuscule walls appeared to contain mainly glycolipid. Young arbuscules, hyphae, and immature vesicles were rich in basic protein. Phenolics were detected in vesicle walls and hyphal attachments, but none accumulated around infected areas even though laccase activity was present in cortical regions occupied by young arbuscules. Dehydrogenases were present in young arbuscules, hyphae, and in immature vesicles still containing noticeable amounts of cytoplasm. Peroxidase and catalase activity in senescing arbuscules were probably associated with fatty acid oxidation in the fungus.

ISSN:0008-4026    

DOI:10.1139/b81-086

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

The apoplastic dyes disodium 4,4′-bis (2-sulfostyryl) biphenyl (Tinopal CBS), a fabric brightener which is bound by cellulose, and trisodium, 3-hydroxy-5,8,10-pyrene trisulfonate (PTS), which is not bound by the walls, were used to trace an apoplastic pathway into the vascular tissues of corn and broad bean roots. The endodermis prevented dye entry into the stele in most regions of roots. However, if the roots were killed prior to dye treatment both dyes entered the steles, indicating that in healthy roots the dyes were confined to the apoplast and were not toxic in the applied concentrations. The more mobile dye, PTS, appeared in the shoots of the plants following a root treatment, indicating that an apoplastic pathway into the stele does exist in the roots. Neither dye penetrated into the steles at the tips of the primary roots. The point of entry in both corn and broad bean was located along the margin of a secondary root which had recently emerged from the epidermis of the primary root. The dyes did not enter the steles of the primary roots during earlier stages of secondary root development, nor did they enter through the secondary root primordia themselves.

ISSN:0008-4026    

DOI:10.1139/b81-087

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Sporulation inAlternaria cichoriiNattrass was induced by near ultraviolet irradiation (< 340 nm) and inhibited by blue light. The inhibitory action of blue light could be reversed by near ultraviolet irradiation. Induction by near ultraviolet could be annulled by subsequent exposure to blue light. Sporulation during a sequential exposure to blue–near ultraviolet light was always determined by the quality of the last irradiation applied. A series of alternating doses of blue–near ultraviolet light ending in near ultraviolet promoted sporulation whereas a series ending in blue light inhibited sporulation. This is considered strong evidence for the existence of an interconvertible pigment system absorbing at the blue and near ultraviolet regions of the spectrum which controls sporulation inA.cichorii.

ISSN:0008-4026    

DOI:10.1139/b81-088

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Endophytic fungi were isolated from foliage of four host species of Cupressaceae sampled from 19 sites in Oregon.Chamaecyparis lawsonianaandThuja plicatashowed high overall rates of infection (30–50%) whileCalocedrus decurrensandJuniperus occidentalisshowed lower rates (10–35%). For any particular host, samples from homogeneous stands with a closed canopy showed higher infection rates than those from mixed stands with an open canopy. For a given tree, infection rates tended to increase with increasing foliage age and decreasing distance from the trunk (exceptions are noted in the text below). The most commonly isolated endophytes includeLinodochiumsp. andGeniculosporiumsp. onC.decurrens;Scolecosporiellasp.,Nodulisporiumsp.,Geniculosporiumsp., andChloroscypha alutipesonC.lawsoniana;Retinocyclus abietisanamorph andHormonemasp. onJ.occidentalis; andChloroscypha seaverionT.plicata.

ISSN:0008-4026    

DOI:10.1139/b81-089

出版商:NRC Research Press    

年代:1981

数据来源: NRC