摘要:

Five-day-old seedlings of wheat were placed in an atmosphere of C14O2and permitted to carry on photosynthesis continually for 7 to 8 days. At the end of this time the leaves were extracted with 85% ethanol. The alcohol-insoluble residue was hydrolyzed with 1 Nhydrochloric acid. The hydrolyzate was deionized, concentrated, and streaked on Whatman No. 3 MM paper. The sugars were separated by one-dimensional chromatography in butanol/pyridine/water and found to be present in the following relative amounts: glucose > xylose > arabinose > galactose.

ISSN:0008-4026    

DOI:10.1139/b57-001

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

The work concerned some chemical and physiological characteristics of sugar beet seedlings grown in darkness in vermiculite moistened with water or with 4, 8, 12 p.p.m. solutions of TCA (sodium salt of trichloroacetic acid) or of Dalapon (sodium salt of 2,2-dichloropropionic acid). The chemical treatments, which were effective in improving the cold resistance of the seedling shoots, decreased their moisture content, increased their rate of water loss, and decreased their resistance to desiccation; increased the sugar and the dry matter content; and had no appreciable effect on the amount of total nitrogen or of water soluble nitrogen in the seedlings.

ISSN:0008-4026    

DOI:10.1139/b57-002

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

Chromatographic evidence indicated that glucose, fructose, and sucrose were present in wheat stems and leaves at stages of growth from early shot blade to maturity. A number of non-reducing oligosaccharides soluble in 80% ethanol were also present in both leaves and stems during this period. Simultaneously, at least one water-soluble oligosaccharide which is insoluble in 80% ethanol appeared in the stems. All oligosaccharides examined produced only glucose and fructose upon complete hydrolysis with invertase or acid.

ISSN:0008-4026    

DOI:10.1139/b57-003

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

The shoot apex consists of a few initial cells at the tip of a thimble devoid of leaf initials for at least 100 μ. Leaf primorida are initiated from the superficial layer of cells, whereas branch buds arising among the; very youngest leaf primordia are produced deeper in the apex. Chinks occur where three or more cell walls come together. The tissue of the stem for the first 200 μ has no internodes. Two squamulae intervaginales lie on the adaxial surface of each leaf with which their development is associated. Internodes are initiated by the longitudinal growth and division of cells from the bottom of the leaf insertion disks. Cells of the young node divide longitudinally to increase the diameter of the nodal disk and to split the intercalary meristem into segments. Internodes are thus initiated with lacunae. Cells destined to become wood vacuolate at the seventh leaf whorl. Scalariform thickenings are produced but quickly disintegrate along with the rest of the xylem cells leaving a lacuna in the center of the stem. The bast surrounding the central xylem differentiates only slightly, beginning at the 20th leaf whorl, whereas the leaf traces and vertical cortical strands are apparent in younger tissue.

ISSN:0008-4026    

DOI:10.1139/b57-004

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

The extraction of enzymes concerned with malic acid metabolism from succulent plants, notablyBryophyllum calycinum, has been made possible by the introduction of a new technique. The high concentration of organic acids in the vacuoles of leaf cells was neutralizedin situby vacuum infiltration with ammonia solution. Thus, during maceration, the enzyme proteins are neither precipitated nor inactivated and conventional methods of enzyme purification may be applied. Further experiments have shown that whereasB.calycinumplants may lose their ability to fix carbon dioxide actively in the dark following exposure to short days (hours) the enzymes involved in malic acid metabolism and carbon dioxide fixation in the dark are not necessarily depleted.

ISSN:0008-4026    

DOI:10.1139/b57-005

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

A method of obtaining sterilized wood blocks much less drastic than those presently in common use has been developed. The treatment is sufficiently mild that only the most superficial of the living parenchyma cells are killed. Samples of balsam fir wood treated by this technique have been successfully inoculated in specially designed tubes with three fungi that attack recently killed balsam in nature. The technique shows promise of reducing the problem of correlating field and laboratory studies of wood decay by avoiding the marked changes in the wood which result from most sterilization methods.

ISSN:0008-4026    

DOI:10.1139/b57-006

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

Amounts of sedimentary chlorophyll degradation products were determined for surface sediments from nine Connecticut lakes. The relationship between sedimentary chlorophyll degradation products in the ignitable matter of the mud and the hypolimnetic oxygen deficit: was not significant at the 5% level, nor was the relationship between the former and the average summer seston chlorophyll. Shallow water sediments tended to have lesser amounts of sedimentary chlorophyll degradation products than deep water sediments.

ISSN:0008-4026    

DOI:10.1139/b57-007

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

A new species,Phomopsis cucurbitae, is described as the chief causal agent of a black rot disease of greenhouse cucumbers in Ontario. In addition to causing stem canker, the fungus occasionally causes decay of fruits. Similarities in macroscopic symptoms caused byP.cucurbitaeand by another fungus,Mycosphaerella melonis, that also causes black rot of cucurbits, are pointed out. The pathogenicity ofP.cucurbitaeon cucurbits and tomato is discussed.

ISSN:0008-4026    

DOI:10.1139/b57-008

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

A description of the morphological characteristics of sprigs grown in the dark is given. Among the factors that may be responsible for the pattern of growth there is the absence of direct light stimulus, the effect of the sugar solution, the lack of auxins, and the oxygen factor. Experimental evidence suggests that the lack of light per se has little effect upon the form ofElodea. Indole-3-acetic acid in the concentrations used indicate only a stimulation of root production. The effect of the sugar solution appears quite noticeable. Gaseous exchange in cotton-plugged flasks is of significance particularly in dim light. Also, in plants grown with and without added oxygen, in darkness and light, it has been established that the relative amount of oxygen is a major factor influencing not only the size of cells in the leaves and internodes but also the type of air space produced. Finally, changes of gas pressure within the intercellular spaces do enlarge these spaces so that lacunae can be made to occur even in the apical cone.

ISSN:0008-4026    

DOI:10.1139/b57-009

出版商:NRC Research Press    

年代:1957

数据来源: NRC

摘要:

A comparative study of fungitoxicity and phytotoxicity was made with an homologous series of N-n-alkylethylenethioureas ranging from ethyl to dodecyl. Water solubility decreased and the oil/water partition coefficient increased with increasing length of alkyl side chain. Fungitoxicity increased with increasing chain length up to and including the octyl homologue followed by a sharp decline in the higher members of the series. The more fungitoxic homologues had the same mode of action and the cutoff in toxicity was due to limiting water solubility.The peak of maximum phytotoxicity depended on the availability of the compounds to the plant cells. As the series was ascended the mobility of the homologues in the plant was found to decrease. When the compounds were readily available to plant cells phytotoxicity increased as the series was ascended up to at least the octyl homologue, but when barriers were present, a peak for phytotoxicity was exhibited near the amyl homologue.Studies on the uptake of the compounds from aqueous solutions by potato tissue andMonilinia fructicolaspores showed that a distribution equilibrium existed between the tissue or spores and the external solution. With increasing length of side chain the affinity for the biophase increased and hence the differential toxicity could be attributed to the partitioning of the chemical between the two phases.

ISSN:0008-4026    

DOI:10.1139/b57-010

出版商:NRC Research Press    

年代:1957

数据来源: NRC