摘要:

Effects of 2,4-D and picloram at 50 and 100 ppm on early development ofPinus resinosaseedlings were studied. Both herbicides caused abnormal development of pine seedlings. After seeds germinated, the first conspicuous effect of 2,4-D treatment was cessation of root elongation. Proliferation and expansion of parenchyma cells in the stem and cotyledons were also stimulated by 2,4-D, causing abnormal thickening of seedlings. Disorganization and collapse of parenchyma cells in the upper stem were followed by callus formation. Cotyledons of 2,4-D-treated plants developed abnormally. Formation of vascular strands was retarded. Division and expansion of mesophyll cells were stimulated by 2,4-D causing decrease in intercellular spaces. Numbers of stomata and chloroplasts were lower in cotyledons of treated plants than in controls. Cotyledons of treated plants were fused to primary needles. Expansion of early formed primary needles and initiation and expansion of additional primary needles were inhibited by 2,4-D. Effects of picloram on pine seedlings were somewhat similar to effects of 2,4-D but picloram appeared to be more toxic at comparable dosages.

ISSN:0008-4026    

DOI:10.1139/b71-246

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Most ecological studies of chytrids and chytridiaceous fungi in soils are primarily distributional, and autecological information for particular species is scant. In this study the distribution of 11 species,Schizochytrium aggregatum, Thraustochytrium roseum, Chytriomyces hyalinus, Rhizophlyctis harderi, Rhizophydiumsp. (utriculare?),R. sphaerocarpum, R. carpophilum, R. sphaerotheca, Phlyctochytrium chaetiferum, P. palustre, andP. reinboldtae, is numerically expressed by an index (DII) derived from occurrence and frequency for 19 habitats. Mean values of various environmental parameters—pH, organic matter, bulk density, osmolarity, Ca2+, Mg2+, and Na+—are calculated for each habitat, and linear correlations of DII against means of the environmental factors of each habitat are calculated for each species. Also the range, mean, and standard deviation of chemical and physical parameters at sites where each species occurs are calculated. By these methods some autecological facts appear for each species. Basically the fungi are divisible into four groups: (1) obligately marine,S. aggregatum; (2) marine,T. roseum; (3) facultatively marine,C. hyalinus, R. harderi, R. sphaerocarpum, P. chaetiferum, R. carpophilum, R. sphaerotheca, Rhizophydiumsp. (utriculare?); and (4) marine occasionals,P. palustre, P. reinboldtae. Problematic aspects of the study are discussed and another line of investigation is proposed.

ISSN:0008-4026    

DOI:10.1139/b71-247

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Temperature and salinity responses of 57 isolates of various taxa of the Chytridiales and Blastocladiales were determined after maintenance of isolates under controlled conditions for a minimum period of 6 months. Differences and similarities among isolates generally seem constant in time and over several isolates of the same species from the same collection. Since these differences and similarities within a species tend to correlate with habitat types, they possibly represent ecotypes.

ISSN:0008-4026    

DOI:10.1139/b71-248

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The translocation of14C-assimilate in sugar beet can be stopped at the top of the petiole when cyanide (pH 7,0.5 M) is applied to the petiole about 12 cm from the base of the blade 3 min before the14CO2assimilation. Such an inhibition persists for at least 50 min. The possible retarding effect of cyanide on photosynthesis, the loading process of sugar into the venation, and movement of sucrose along the conduit have been investigated by chromatographic analyses of the photosynthetic products and by radioautography of the14C movement in the leaf blade. The cyanide moves rapidly upward from the point of application in the petiole, but does not affect the photosynthetic or loading processes in the leaf blade. The results suggest that a cyanide-sensitive mechanism located in the phloem tissue along the conducting pathway is essential to maintain the normal rapid movement of assimilate from the source to the sink.

ISSN:0008-4026    

DOI:10.1139/b71-249

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The structure of protein bodies from cotyledon tissue of dormant squash seeds was studied using several different preparative techniques. Four major components, the proteinaceous matrix, the protein crystalloid, the soft globoid, and the globoid crystal were found and verified to be present in protein bodies from the large mesophyll cells. Some of these four components were found to be absent in protein bodies of epidermal cells or in protein bodies near the nucleus of mesophyll cells. The globoid crystal, which was hard and electron dense after osmium fixation, is probably the site of phytin storage. The globoid crystal was usually surrounded by the soft globoid, a material of undetermined composition which tended to smear during freeze-etching. Some protein bodies contained several of these globoid regions although most protein bodies seemed to have only one globoid region. One or several protein crystalloids were usually found in protein bodies. Both the protein crystalloids and the globoid regions were surrounded by a proteinaceous matrix substance.Glutaraldehyde–permanganate fixation of tissue clearly showed the presence of the proteinaceous ground substance and the protein crystalloid but the globoid structures were absent. In tissue chemically fixed with glutaraldehyde–osmium all four components were sometimes found but interpretation, on the basis of this fixation alone, was difficult because of the presence of fixation artifacts. Isolation of protein bodies from cotyledon tissue made faster and better quality osmium or glutaraldehyde–osmium fixations possible. In such protein body pellets all four components were seen. Freeze-etching of tissue verified the presence of the globoid crystal and the soft globoid in most protein bodies from cotyledon mesophyll cells. In dormant seed tissue the two proteinaceous components usually were not distinguishable by the freeze-etching technique however. Thus only through the use of several different preparative techniques was it possible to locate and verify the presence of the various structural components in protein bodies from squash cotyledons.

ISSN:0008-4026    

DOI:10.1139/b71-250

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The expression of adult plant oat stem rust resistance conferred by genepg-11is associated with a reduction of chlorophyll and carotenoid pigments in the leaf and stem tissue. Seedlings that possess genepg-11are susceptible to stem rust and have near normal pigment levels but with increasing age the pigment content decreases more rapidly than in plants without the gene and the plants become moderately resistant to stem rust. The ratio of chlorophyll to carotenoids remains unchanged at all stages of plant development. This gene has effects unlike any other known gene for stem rust resistance in oats.

ISSN:0008-4026    

DOI:10.1139/b71-251

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Starch composition (amylose content) and the activities of starch-synthesizing enzymes were determined in cultures ofPolytoma uvellaand potatoes kept at various temperatures. In general ADPG-α-glucan glucosyltransferases were much less thermostable in vivo than P- and Q-enzymes. Potato phosphorylase proved to be the most stable enzyme. InPolytomaboth P/Q ratio and amylose content decreased at 30 °C, whereas they remained unchanged in potatoes grown at 30 °C. This confirms the results from earlier experiments which indicated that the P/Q ratio is correlated with amylose content, and is also in agreement with the simultaneous increase in amylose percentage and P/Q ratio observed during the development of starch granules in corn endosperm. The results are discussed in relation to the problem of amylose production in starch granules and the importance of phosphorylase in starch synthesis.

ISSN:0008-4026    

DOI:10.1139/b71-252

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Leaf extracts of three highly variable, heterophyllus varieties ofS. gramineawere studied using two-dimensional paper chromatography. Inter- and intra-population variation in phenolic patterns were analyzed and compared with statistical analyses of morphological variation. Infraspecific chemical variation showed a high correlation with previously established ecotypic differentiation of taxa. Individual plant phenolic patterns of phyllodial, submersed leaves differed from those of emersed leaves, indicating that environmental parameters modify production of phenolic compounds. Since ecotypic differentiation in all taxa within the complex is not detectable by morphological characters, a possible explanation for the lack of correlation between morphological and chemical evidence is discussed.

ISSN:0008-4026    

DOI:10.1139/b71-253

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The phenolic compounds in leaf material of 52 taxa of the Caprifoliaceae representing 11 genera have been examined. The cyanogenetic glycoside sambunigrin was found to occur only in certain members ofSambucus. Chlorogenic acid isomers and simple phenolic acids were identified in all taxa examined; coumarins were of more limited distribution. The flavonols kaempferol and quercetin, considered to be primitive chemical types, occur most frequently inViburnum, Sambucus, andWeigela. The flavones apigenin and luteolin, more advanced types, are predominant inSymphoricarpos, Triosteum, andLonicera. Amentoflavone, a biflavonyl derivative, has been found in two species ofViburnum, substantiating an earlier report of its existence in this genus. This is also taken to represent a primitive chemical type which supports the contention thatViburnumis one of the more primitive genera in the family. A number of other relationships within the family are discussed in light of the chemical data.

ISSN:0008-4026    

DOI:10.1139/b71-254

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The effect of small increments of direct current on the growth and ion uptake in Scotia tomato plants was determined. The natural endogenous current in the plant was first assessed and the current applied to reinforce or oppose the natural with three treatment durations per day. Significant increases in linear growth (5 to 30%) were obtained and also significant increases in uptake by the plants of K, Ca, and P when currents were between 15 and 3 μA per plant with the plant negative to the ground. A reduction in growth occurred when the plants were treated with 15 μA positive to the ground or with any currents of magnitude greater than 30 μA per plant. The increased ion accumulation seems not to be merely a passive movement under the applied potential, and it is thought that small currents may stimulate active ion pumps or alter the internal distribution of growth-regulating compounds in a somewhat erratic manner.

ISSN:0008-4026    

DOI:10.1139/b71-255

出版商:NRC Research Press    

年代:1971

数据来源: NRC