摘要:

An unidentified substance(s), provisionally named P310, is produced in mycelia ofAlternaria chrysanthemi, Ascochyta pisi, Ophiobolus graminis, Pleospora herbarum, andPyronema omphalodeswhen sporulation has been induced with near-ultraviolet radiation. This same substance is absent in non-sporulating colonies grown in darkness. It is, however, present in unexposed colonies ofA. pisigrown on media which are able to support sporulation in the absence of light. P310is extractable with cold absolute ethanol, is water-soluble, passes through a dialysis membrane, is retained on a cation exchange resin, and appears to be composed of at least four possibly related substances. Maximum absorption of P310is between 260 and 340 mμ (310 mμ maximum) and below 250 mμ. P310may exist in an oxidized state for when reduced electrolytically, absorption between 260 and 340 mμ is lost. P310can be detected spectrophotometrically in extracts of colonies exposed to 6 hours of near-ultraviolet radiation, but not after a 1 hour exposure. Conidiospores ofA. pisicontain P310, which may be a "sporulating factor" associated with these spores. The rate of P310production in irradiated colonies appears to be related to length of exposure, yet this substance can be produced in darkness for a limited period following stimulation of colonies by near-ultraviolet radiation. Neither the identity nor themodus operandiof P310has yet been demonstrated.

ISSN:0008-4026    

DOI:10.1139/b65-024

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

The fluorescent substances in un-infected and virus- or rust-infected primary bean leaves were examined by paper chromatography 11 to 20 days after seeding.A relatively constant total of 17 fluorescent materials was recorded in normal leaves. For local, necrotic virus infections, totals of 20 additional fluorescent materials were recorded betweenand 7 days after inoculation for tobacco necrosis (TNV) and 15 betweenand 9 days for tobacco mosaic (TMV). Thirteen of the new materials in TMV infections appeared to be the same as some of those from TNV infections, but were quantitatively greater for the more extensively necrotic TNV lesions. One of the most prominent metabolites associated with the hypersensitive virus infections was occasionally present in trace amounts following mild leaf abrasion.Only eight materials additional to those in healthy leaves were detected in extracts from non-necrotic rusted tissue between 1 and 6 days after inoculation. Five of these were tentatively identified as common to both TNV and TMV infections and a sixth as common to TNV infections. No abnormal fluorescent materials were recorded from inoculated leaves bearing symptomless 3-day-old infections of bean strain of TMV and only a trace of one 8 days after inoculation. A rough correlation was apparent between the degree of necrosis and formation of new fluorescent compounds.Abnormal fluorescent materials were also detected in cowpea leaves bearing local lesion infections of TNV. Many of these were different from those of TNV-infected bean. The appearance of abnormal fluorescent compounds coincided with incipient virus lesion formation on bean and cowpea.Six fluorescent materials in healthy bean were tentatively identified as derivatives of caffeic acid,p-coumaric acid, or quercetin. Six major abnormal fluorescent metabolites in bean showed evidence of phenolic nature.

ISSN:0008-4026    

DOI:10.1139/b65-025

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

Results from controlled inoculation experiments show that conifers of six genera (Abies, Larix, Picea, Pinus, Psendotsuga, andTsuga) are susceptible to the poplar (Populus) rusts of western Canada. Twenty-one new host records are established. It is suggested thatMelampsora albertensisArth. be reduced to synonymy withM. medusaeThüm., because they appear to be indistinguishable from each other in morphology, life history, host range, and host reaction.

ISSN:0008-4026    

DOI:10.1139/b65-026

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

The problem of species concepts and delimitation in the heteroecious rusts is discussed. It is illustrated byPuccinia karelica, which is known in typical form from Europe, southern Alaska, coastal British Columbia, and apparently Kamchatka and Saghalien. A distinct population in eastern Canada and adjacent United States is named ssp.laurentinassp. nov.P. karelicais compared with closely related species and its probable mode of evolution is discussed.

ISSN:0008-4026    

DOI:10.1139/b65-027

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

Nine species ofGymnosporangiumnative to Eastern Canada and one commonly intercepted on imported nursery stock, but not known to be established, are described, illustrated, and discussed. Species occurring in adjacent United States but unknown in Eastern Canada are briefly mentioned.G. connersiisp. nov. andRoestelia brucensissp. nov. are newly described onJuniperus horizontalis. R. brucensisis noteworthy because it has a repeating aecial stage and lacks telia. This is the first example of repeating aecia occurring in the genus. Aecial and telial keys are presented, emphasizing characters that permit identification in the field. One such character is the date of aecial maturity; it is suggested that this is a ready means of verifying apparent differences in morphology between taxa in this genus.

ISSN:0008-4026    

DOI:10.1139/b65-028

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

The quantity and kind of radioactive compounds in the blade, main rib, and petiole of sugar beet leaves were determined at intervals up to 3 hours after a 1 minute period during which the blade photosynthetically assimilated C14O2. During the first 5 minutes, radioactive compounds were isolated from the main rib but these were due to the direct assimilation of C14O2by the rib and not to translocation into the rib. After 8 minutes, radioactive sucrose from the blade reached the rib and began to move down the petiole. This movement continued at a steady rate of about 1% of the assimilated C14per minute for about 1 hour. The concentration of C14per 2 cm section of petiole was a linear function of the distance, and this gradient moved down the petiole with an apparent velocity of 50 to 135 cm per hour. After 1 hour, the entire length of the petiole contained radioactive sucrose at a relatively uniform concentration per unit section. Although the blade still contained 40 to 50% of the assimilated C14in sucrose, movement out of the blade was reduced to a very low rate after 1 hour, but radioactive sucrose continued to leave the petiole for an additional hour. The absence of significant metabolism of the radioactive sucrose in the petiole, combined with the changes in gradient of that sucrose as a function of time, suggest that the petiole exerts a relatively passive role in the translocation process.

ISSN:0008-4026    

DOI:10.1139/b65-029

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

After dark fixation of C14O2by salt marsh obligate halophytes, most of the 80% ethanol-soluble label appeared in the amino acid fraction. Species tested wereBatis maritimaL.,Salicornia europaeaL.,Salicornia virginicaL., andBorrichia frutescens(L.) D.C.A time study was made of the dark fixation products of C14O2bySpartina alternifloraLoisel, a facultative halophyte, cultured with and without NaCl in the nutrient medium. In this species the greater proportion of label was recovered from amino acids (principally aspartic and glutamic acids) at times of 1 hour and less, the pattern changing to favor organic acids at longer times, mainly malic acid in NaCl-free plants. The shift to organic acids was slower in plus NaCl plants with aconitic and an unidentified acid appearing along with malic as the principal labelled acids.NaCl reduced the rate of C14O2assimilation bySpartina alterniflora. Initially, the fixation pattern resembled that of obligate halophytes, becoming more like that of terrestial plants (glycophytes) after 1 hour.

ISSN:0008-4026    

DOI:10.1139/b65-030

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

The curve of growth in length of the main axis of excised tomato roots, grown in a 6-day passage, shows a 'lag phase' at the beginning and a decrease in growth rate toward the end of the passage when growth of the apex is inhibited by the older tissues. The 'lag phase' is neither due to transfer of the excised tip to fresh medium nor a consequence of the developmental stage at which the tip is excised. The 'lag phase' may mean that the apical meristem requires substances supplied by the older tissues, but it is, at least in part, due to injurious effects of excision.From surgical experiments it is concluded that the growth of lateral roots is promoted by the presence of older tissues and inhibited by the main apex and younger parts of the main axis. A comparison is made between this latter effect and apical dominance in shoots.Growth of the main axis was increased by 2,4-dichloroanisole (DCA). Growth of the lateral roots was inhibited at concentrations of 3-indolylacetic acid (IAA) and DCA which did not affect growth of the main axis. This effect was not observed with 1-naphthaleneacetic acid (NAA). At concentrations which did not affect growth of the main axis, only NAA promoted the formation of lateral roots. The evidence is reviewed that the growth correlations in the root involve 'auxin-type' growth regulators but that different regulators may be involved in the different growth correlations.The author acknowledges the loan of apparatus from the U.S. Office of Naval Research.

ISSN:0008-4026    

DOI:10.1139/b65-031

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

Adaptations of Weatherley's relative turgidity technique (Weatherley 1950), fitting it for use with red pine (Pinus resinosaAit.), white pine (P. strobusL.), balsam fir (Abies balsamea(L.) Mill.), and eastern hemlock (Tsuga canadensis(L.) Carr.) are described. Results of preliminary investigations of sampling variation between trees, whorls, and needle ages in red pine are presented.

ISSN:0008-4026    

DOI:10.1139/b65-032

出版商:NRC Research Press    

年代:1965

数据来源: NRC

摘要:

Development of the megasporangiate cone during the period of enlargement and maturation following dormancy is described in detail. This work, in conjunction with the early development previously described, provides a complete description of the 17 month developmental cycle. Growth of the megasporangiate cone is resumed in early March near Corvallis, Oregon, and the cone buds burst about 1 month later. The cone elongates rapidly by intercalary growth. Bracts enlarge but the shape of the bract established prior to dormancy is essentially maintained. The scale assumes a spoon-shaped appearance as a result of a form of marginal growth. Vascularization, and development of other tissues within the bract and scale, indicates that bracts are homologous to leaves and basically similar in structure, but scales are highly modified fertile lateral shoots. Each bract is supplied by a single leaf trace and each scale by two separate branch traces. The seed wings differentiate from adaxial surface layers of each scale. A large zone of macrosclereids differentiates in the basal abaxial portion of the scale. The cone reaches its maximum size early in July and maturation of tissues occurs in July and August, and is generally complete early in September. Cone opening results from drying and shrinkage of the macrosclereids at the base of the scale.

ISSN:0008-4026    

DOI:10.1139/b65-033

出版商:NRC Research Press    

年代:1965

数据来源: NRC