摘要:

Detached primary wheat leaves and attached cotyledons and primary leaves of snapdragons were allowed to photoassimilate C14O2for short periods of time. They were subsequently kept in air and samples were taken at various time intervals and analyzed for protein nitrogen, and amounts and total radioactivities of soluble sugars and amino acids and protein amino acids. A method of estimating protein turnover from these data is discussed. Amounts and specific activities of respired carbon were also determined for wheat leaves.Minimum protein turnover rates of about 0.5 to 1.5% per hour were found in rapidly growing snapdragon leaves and in snapdragon cotyledons. Lower rates were found in detached, non-growing wheat leaves and slowly growing snapdragon leaves. Little contribution could have been made by proteins as substrates for respiration in detached wheat leaves. It is suggested that protein turnover in leaves is mainly associated with growth and biochemical differentiation.

ISSN:0008-4026    

DOI:10.1139/b63-081

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Attached, rapidly growing wheat leaves were allowed to photoassimilate C14O2and C12O2alternately. Samples of leaves were collected after each period of photosynthesis and were analyzed for amounts and total activities of soluble sugars and amino acids, and protein amino acids. The leaves were also analyzed for protein nitrogen and amounts and total activities of respired carbon. Samples of roots were also collected and the amounts, total activities, and specific activities of their soluble compounds were determined. It was possible to calculate from these data the proportions of carbon entering some protein amino acids which came either from soluble amino acid pools or by a direct route from photosynthate, bypassing the soluble pools. More than half of the carbon entering protein-bound serine and glycine was derived from newly assimilated CO2, while protein glutamic acid, aspartic acid, and alanine derived more of their carbon from the soluble amino acid pools. Analysis of the data from roots indicated that a considerable portion of the carbon translocated from the leaves was derived from newly assimilated CO2. There was some indication that protein turnover took place, but it was concluded that proteins could not have contributed significantly as substrates for respiration in these leaves.

ISSN:0008-4026    

DOI:10.1139/b63-082

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Most of the radioactive glucose incorporated into the α-cellulose of sugar beet and barley leaves during short-term photosynthesis in C14O2can be removed in a small proportion of weight by digesting the cellulose in hot, dilute trichloroacetic acid solution. This acid-soluble component contains little or no free labelled glucose. The radioactivity resides in a glucosan of sufficiently high degree of polymerization that it readily and irreversibly precipitates from solution. The radioactive glucosan is resistant to acid hydrolysis but is readily hydrolyzed by cellulase.While the total radioactivity in the α-cellulose fraction does not increase significantly after 10 minutes following cessation of C14O2administration, a slow transfer of radioactivity from the acid-soluble component to the acid-insoluble residual cellulose can be measured over a period of several hours. The transfer is hastened by holding the leaves in darkness. Both the initial incorporation and the subsequent transfer are blocked by physical alteration of the leaf structure through grinding or freezing and thawing. These results are interpreted as evidence for the participation of a polymeric glucosan as an intermediate in the biosynthesis of leaf cellulose.

ISSN:0008-4026    

DOI:10.1139/b63-083

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

To find a higher plant suitable for the biosynthesis of mannitol-C14, detached leaves of 20 species were illuminated in the presence of C14O2and subsequent distribution of C14among their sugars was determined. Mannitol-C14was found in 4 species, verbascose-C14in 3, stachyose-C14in 9, raffinose-C14in 16, mellibiose-C14in 2, maltose-C14in 15, sucrose-C14in 20, galactose-C14in 8, glucose-C14in 17, and fructose-C14in 12.Syringa vulgarisL. andFraxinus americanaL. were found to be the most suitable plants for the preparation of radioactive mannitol of high specific activity. The yield was 19.6% inSyringa, with specific activity = 38.4 μc/mg, and 8.4% inFraxinus, with specific activity = 68.5 μc/mg.

ISSN:0008-4026    

DOI:10.1139/b63-084

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Detailed morphological and karyological studies have revealed that the North American taxa of theAlisma plantago-aquaticacomplex are most appropriately classified as the two species,A. subcordatumRafin. (2n = 14), andA. trivialePursh (2n = 28). The morphological characters separating these species and distinguishing them from the European diploid,A. plantago-aquaticaL., s. str., are given, and also the chromosome number of American material ofA. gram-ineumGmel. (2n = 14).

ISSN:0008-4026    

DOI:10.1139/b63-085

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Two new species are described in the lignicolous Hyphomycete genusPhialocephalaKendrick, and a key is given to the members of the genus.

ISSN:0008-4026    

DOI:10.1139/b63-086

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Sebacina, Exidiopsis, andBasidiodendron, three genera of the resupinate tremellaceae, are recognized.Sebacina, based onThelephora incrustansPers. ex Fries, is retained (in sensu stricto).Exidiopsis, established forExidia effusaBref., is accepted as a genus. The taxonBourdotia, originally created by Bresadola in 1908 as a subgenus withSebacina(Bourdotia)galziniias the type and in 1913 elevated by Bresadola and Torrend to generic rank, is proposed as a subgenus ofExidiopsis. SinceBourdotia galziniiis the type ofBourdotia, the generic nameBasidiodendroncreated by Rick in 1938 in order to accomodateB. luteo-griseumis reinstated for the arid-reticulate gloeocystidiate species formerly included inBourdotia. Two subgenera ofBasidiodendrcnare recognized, namely the type subgenusBasidiodendronestablished forB. luteo-griseumRick andAsarcogloeasubg. nov. based onSebacina piniJacks. & Martin. The type subgenusBasidiodendronincludes six species. InAsarcogloea, there are four species involved. Two of these,B. subreniformissp. nov. andB. nodosasp. nov., found in Ontario inhabiting decaying wood, are described for the first time. Taxonomic keys and illustrations are included for these species.

ISSN:0008-4026    

DOI:10.1139/b63-087

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Biochemical properties and chloroplast fine-structure of aviridismutant of Gateway barley are described. The mutant was deficient in chlorophyll and carotenoids when young but developed nearly normal levels of pigment with age (avirescenstype). Etiolated mutant seedlings were low in protochlorophyll. In the young mutant, chloroplasts were small and irregular in shape and they contained large vesicles but no normal lamellae or grana. The level of free amino acids, particularly of serine, was extremely high. These disturbances were overcome with age. It is suggested that the mutation alters the lipoprotein of lamellar structures in the plastid, and that other effects are consequential.

ISSN:0008-4026    

DOI:10.1139/b63-088

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

At Wawa, in northern Ontario, vegetation has been damaged severely by sulphur dioxide pollution from an iron-sintering plant. Damage is mainly restricted to a narrow strip northeast from the sinter plant, since southwest winds are strongly predominant. It is traceable from the air for at least 20 miles in this direction and is estimated as severe within 11 miles and very severe within 5 miles. Within about 10 miles NE. from the sinter plant ground flora variety declines markedly, from about 20–40 species per 40 square meter quadrat beyond this distance to 0–1 species within 2 miles of the pollution source. At the same time sulphate in lake and pond waters increases greatly, from normal levels of about 0.2–0.3 milliequivalents per liter to more than 0.5 meq/l. within 11 miles NE. and up to 2 meq/l. within 2 miles NE. from the sinter plant. Waters within about 5 miles NE. are strongly acid (pH 3.2–3.8), but are not low in calcium. Soluble sulphate in the surface soil rises sharply within about 4 miles NE. from the pollution source, where, also, soil erosion is very pronounced, though traceable farther out.The phanerogams most tolerant of air pollution arePolygonum cilinodeandSambucus pubens, which are infrequent in the normal forest vegetation. In quadrat studies along a northeast transect, seedlings ofpinus strobuswere not observed within 30 miles from the sinter plant, while those ofPicea glauca, P.mariana, andPopulus tremuloideswere not recorded within 15 miles.

ISSN:0008-4026    

DOI:10.1139/b63-089

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

This paper reports significant extensions of range for 71 vascular species and discusses the occurrence of several of these plants in relation to postglacial development of the flora of westcentral Alberta. Some attention is paid to the coniferous vegetation of the region, especially those faciations in which certain of the more interesting species occur. The alpine fir and black spruce faciations are regarded as edaphic climax types in the upland forest. Species new to Alberta include the "eastern"Rhynchospora capillacea, the rareSparganium glomeratum, and the "Pacific"Streptopus streptopoidesvar.brevipes. Two other "Pacific" species,Angelica genuflexaandTiarella trifoliata, previously known in the area from isolated collections, are now reported as widespread and locally abundant. Floristic data support the hypothesis of a fluctuating ice-free corridor as a refugium in western Alberta during the late Wisconsin or soon thereafter, and point to Manitoba–Saskatchewan–Alberta as a vast meeting ground of "eastern" and "western" biota.

ISSN:0008-4026    

DOI:10.1139/b63-090

出版商:NRC Research Press    

年代:1963

数据来源: NRC