摘要:

The quantitative variation of needle flavonoids within and between different clones ofLarix leptolepiswas determined for leaves growing both on short and on long shoots. Minor quantitative differences were found between trees on one clone, but between different clones large variations occurred, especially for the C-glycoflavone vitexin. Needles growing on long shoots contained more kaempferol-3-(p-coumarylglucoside) and other acylated glycosides and somewhat more vitexin than short-shoot needles, but less kaempferol-, isorhamnetin-, and quercetin-and (or) laricitrin-3-glycosides. No correlation could be found between needle flavonoids and the resistance of some clones toGuignardia laricina.

ISSN:0008-4026    

DOI:10.1139/b80-267

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Four additional structural similarities between the roots ofIsoetesandStigmariaare reported. Proximal swellings and connectives are reported for the first time inIsoetesroots. The size ranges of the roots ofIsoetesandStigmariaare shown to overlap, and a definite epidermis is described for the first time on the roots ofStigmaria. The structural diversity present among the roots of various lycopods is reviewed. It is concluded that the root is of polyphyletic origin within the Lycopsida. The roots ofLycopodiumandSelaginellashow many similarities with stems and are considered to be derived from the stems of some rootless ancestor, whereas the roots ofIsoetesand the lepidodendrids show many similarities with their own leaves and are considered to be derived from leaves or from some less specialized appendages from which both the leaves and roots of these plants were derived.

ISSN:0008-4026    

DOI:10.1139/b80-268

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

The aluminium, potassium, sulphur, titanium, and vanadium contents of the lichensCladina arbuscula(Wallr.) Hale and W. Culb.,Evernia mesomorphaNyl., andHypogymnia physodes(L.) Nyl. were determined for up to 69 sites in the Athabasca oil sands area in northern Alberta. The element accumulation by these lichens was related to both gaseous and particulate emissions from industrial sources and to a localized windblown dust component. The deposition of atmospheric emissions around an oil-extraction plant as measured by lichen thallus concentration closely followed the distribution patterns measured by physical and chemical methods. Visible changes in the thallus condition appeared to be related to the element concentrations.

ISSN:0008-4026    

DOI:10.1139/b80-269

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

When plants have been submitted to a short inductive phase, then to a long dysperiodic phase, and finally to inductive conditions again, one or several branches, with or without subtending leaves, develops on some inflorescences above a series of flowers. These branches constitute a morphological inflorescence reversion, and the axis which carries them is called "α axis." Maximal vegetative characteristics are found at the basal part of a reversion. When several consecutive axes are a axes, the most vegetative reversion (maximal reversion) is developed on the lowest of these axes. Some more or less abnormal structures, such as a series of bracts, an axis with a "terminal" flower, proliferated flowers, or virescences, are sometimes inserted between typical flowers and branches on the edge of the reversed region.Apart from inflorescences, some gradients are different from those shown by plants maintained in inductive conditions: the slope of the "axillary relativity" curve is reversed, and the final length gradient of the six upper leaves of the main axis is attenuated.

ISSN:0008-4026    

DOI:10.1139/b80-270

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Neutral sugar compositions of materials released from isolated mycelial walls of race 1 and race 2 ofFusarium oxysporumf. sp.lycopersiciandFusarium oxysporumf. sp.cubensewere similar (5% ribose, 52% mannose, 28% galactose, 15% glucose). High molecular weight glucans were isolated by ion-exchange chromatography from the cell wall extracts of each of theFusariumisolates. The linear chain linkage structure of theFusariumglucans was predominantly 1—3 and 1—6. That of theColletotrichum lindemuthianumglucans was 1—3 and 1—4. TheseFusariumglucans were nearly as effective as glucans fromColletotrichumspecies at eliciting browning and phytoalexin production in green bean cotyledons. Tomato fruit and stem tissue showed browning and phytoalexin production when exposed toF. oxysporumf. sp.cubensespores. These symptoms did not develop upon treatment of tomato tissues with theFusariumorColletotrichumglucans that had elicitor activity in green bean.

ISSN:0008-4026    

DOI:10.1139/b80-271

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

After imbibition and germination, oat grains pass from a stage where they are insensitive to desiccation to a stage where they are sensitive. Desiccation of germinating grains results in more rapid completion of germination upon rehydration. However, when the initial imbibition (i.e. predesiccation) time of the grains is taken into account, the total time that the seeds are hydrated before germination is completed is the same as control (once-imbibed) grains. Hence it appears that events occurring prior to desiccation do not have to be repeated for germination to be completed. Grains desiccated during germination commence protein synthesis more quickly, and reform polysomes more quickly, than control (once-imbibed) grains. Likewise, RNA synthesis resumes more quickly. Desiccation of grains during the desiccation-sensitive stage results in almost total impairment of protein and RNA synthesis upon subsequent rehydration. Both ribosomes and poly(A)+-containing RNA are conserved in embryos desiccated during the insensitive stage, but poly(A)+-containing RNA is lost from embryos desiccated during the sensitive stage and there is a further decline upon subsequent rehydration.

ISSN:0008-4026    

DOI:10.1139/b80-272

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Avenacoleoptile sections were incubated with or without cycloheximide (CHI) in solutions containing indoleacetic acid (IAA), fusicoccin (FC), or IAA and FC. Resulting growth, incorporation of [3H]leucine into protein, and uptake of [3H]leucine into an ethanol-soluble fraction were determined. FC-stimulated growth was greater and less sensitive to CHI treatment than IAA dependant growth which was virtually eliminated by CHI. IAA alone had little or no influence on [3H]leucine utilization, whereas FC treatment stimulated [3H]leucine incorporation into protein by 36% and uptake into the ethanol-soluble fraction by 75%. CHI inhibited the incorporation of [3H]leucine label into protein such that no significant difference was observed in radioactivity in protein from control, FC-, or IAA-treated tissue. However, CHI did not inhibit the FC-stimulated uptake of [3H]leucine into the ethanol soluble fraction. Total uptake of [3H]leucine obtained from the sum of radioactivities in the protein and ethanol-soluble fractions was stimulated by FC approximately 54% in the absence of CHI and 92% in the presence of CHI. IAA in combination with FC stimulated a further increase in leucine uptake. It is proposed that IAA and FC stimulate growth through processes which differ in their dependency on protein synthesis, and that FC-stimulated incorporation of label into protein results from FC-stimulated leucine uptake, not FC-stimulated protein synthesis.

ISSN:0008-4026    

DOI:10.1139/b80-273

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Vessels in stems of 'Jefferson' (race 1 resistant and race 2 susceptible) and 'Bonny Best' (race 1 and 2 susceptible) tomato cultivars inoculated withFusarium oxysporumf.sp.lycopersicirace 1 or 2 were examined by scanning electron microscopy. Four days after inoculation of Jefferson with conidia of race 1, the inoculum conidia and resultant hyphae generally were collapsed, whereas in the susceptible host–pathogen combinations the inoculum conidia and hyphae appeared normal. Neither the plants of the resistant nor the susceptible host-pathogen combinations had perforation plates or tyloses within vessel elements capable of trapping conidia or effectively blocking hyphal growth. The perforation plates of all vessel elements are reduced to slightly lipped rims and thus provide unrestricted apertures for hyphal growth and conidial movement in the transpiration stream. In the susceptible host–pathogen combinations, mycelial growth often filled the vessels, but no sporulation was noted. Frequent lateral spread of the pathogen occurred between adjacent vessels through the bordered pit-pairs. Infrequent occurrence of tyloses and a lack of occlusions by tyloses in the resistant host–pathogen combination suggest that vascular wilt resistance within the stem is not due primarily to physical containment of the pathogen in the vessels. Collapsed conidia and hyphae in the resistant host–pathogen combination suggests that fungitoxic materials in the vessels suppress the pathogen and contribute to resistance.

ISSN:0008-4026    

DOI:10.1139/b80-274

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Osmic fixation was used in an ultrastructural study ofAllium cepaseeds, both in the quiescent state and at the beginning of imbibition, in order to complete earlier observations made after glutaraldehyde fixation. In embryonic radicles, various groups of weakly stained lamellar structures looked like endoplasmic reticulum profiles. In these quiescent tissues, osmic fixation revealed many vesicles which appeared to be atypical elements of endoplasmic reticulum.In the first few hours of imbibition, reactive structures were more numerous and more diverse. Cisternae and vesicles of endoplasmic reticulum became typical looking, such as classically described in active tissues of other species.WhenAllium cepaseeds were treated with liquid nitrogen (−196 °C), induced structural alterations depended on the initial state of hydration. Lamellar systems underwent morphological changes. Osmic fixation showed the presence of numerous opaque globules throughout the cytoplasm. These globules seemed to derive from cisternae that appeared to have become fragmented during freezing. [Journal translation]

ISSN:0008-4026    

DOI:10.1139/b80-275

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

An outline is presented for the reclassification of the Chytridiales into two orders based on fundamental differences in zoospore ultrastructure. The new orderSpizellomycetalesincludes species with thePhlyctochytrium–Entophlyctistype of zoospore and alsoKarlingia, Olpidium, andRozella. Four new genera,Spizellomyces, Gaertneriomyces, Triparticalcar, andKochiomycesreplace thePhlyctochytriumcomplex. The revised Chytridiales includes species with theRhizophydium–Chytridium–Nowakowskiellatype of zoospore, as well asSynchytrium,

ISSN:0008-4026    

DOI:10.1139/b80-276

出版商:NRC Research Press    

年代:1980

数据来源: NRC