摘要:

Patterns of allocation of biomass and calorie energy were investigated for 3 years in several populations of the following taxa:Aster acuminatus,A.nemoralis, and their natural hybridAster×blakei.Aster acuminatus, a forest understory species, allocates more biomass and energy to foliage and reproductive effort than the other two taxa.Aster nemoralis, a bog species, allocates more resources to stems and rhizomes thanA.acuminatusand, although average total biomass values were lower, tissues had higher caloric values. ForAster×blakei, two groups of populations showing morphological introgression to either parent were also correlated with resource allocation patterns. Caloric and biomass resource allocation patterns of populations of the three taxa did not vary significantly over the 3-year study period, except forA.acuminatuswhere biomass was significantly lower in 1979 than in the other 2 years. Populations showing higher absolute biomass values had organs with lower energy values. However, when these values were expressed as percentages, the patterns of allocation of biomass and energy were not differentiated within each species. [Translated by the journal]

ISSN:0008-4026    

DOI:10.1139/b88-231

出版商:NRC Research Press    

年代:1988

数据来源: NRC

摘要:

A study of the water status of spruce needles was conducted to characterize the physiology of the dieback disease of spruce in forests of the French Jura. Alterations of needles in the affected trees were observed with scanning electron microscopy. The water content of those trees was lower than that of healthy ones. Analyses of potassium, calcium, and magnesium levels in the needles have not revealed any deficiencies in major elements, but changes in mineral composition of the needles were observed in diseased trees. The direct action of air pollutants on foliage could explain the results. However, climatic, edaphic, and other factors could also be involved in the present dieback disease of forests. [Journal translation]

ISSN:0008-4026    

DOI:10.1139/b88-232

出版商:NRC Research Press    

年代:1988

数据来源: NRC

摘要:

Polypeptides extracted from the urediosporeling walls ofPuccinia graminis triticiwere separated by two-dimensional isoelectric focusing – polyacrylamide gel electrophoresis and stained with Coomassie brilliant blue or silver or electrophoretically transferred onto nitrocellulose membrane and probed for glycosylation using concanavalin A – horseradish peroxidase, soybean agglutinin-biotin – avidin peroxidase labeled, andLotuslectin-biotin – avidin peroxidase labeled. More than 40 proteins were distributed in the gel by silver staining. Forty concanavalin A binding glycopeptides were identified in the blot, but none of them had affinity to soybean agglutinin orLotuslectin. When fungal polypeptides were electrophoretically transferred through a nitrocellulose membrane that was pretreated with wheat leaf proteins, several fungal glycoproteins bound to the plant protein, suggesting that these pathogen wall components bound selectively to host proteins.

ISSN:0008-4026    

DOI:10.1139/b88-233

出版商:NRC Research Press    

年代:1988

数据来源: NRC

摘要:

Treatment with 10 μM taxol or 3 mM colchicine results in the development of similar aberrant morphotypes inViciahajastana (vetch) suspension cultures. After 2 days exposure to either drug, cells exhibit a disruption in polarity (i.e., swelling or spherical morphology). In taxol-treated cells, microtubules are abundant and brightly stained. In the presence of colchicine, microtubules are absent. Calcofluor staining illustrates that in the presence of taxol the microfibrils appear as thick ordered bundles, while in the presence of colchicine, microfibril bundles are smaller and exhibit less detectable order. The presence of thick bundles of microfibrils is confirmed in taxol-treated cells by the analysis of birefringence patterns. Walls of colchicine-treated cells exhibit a patchy birefringence pattern in polarized light, with adjacent patches exhibiting different order. Although taxol-treated cells contain abundant microtubules, their morphology and wall deposition resemble those of cells that lack microtubules. These observations indicate that the dynamics of microtubules may be important to their proper functioning in cell wall deposition. The differences in wall morphology between taxol- and colchicine-treated cells may reflect the different mechanisms of action of these two drugs.

ISSN:0008-4026    

DOI:10.1139/b88-234

出版商:NRC Research Press    

年代:1988

数据来源: NRC

摘要:

The living stems of striped maple (Acer pensylvanicumL.) at two sites in Nova Scotia were found to be covered by a striking pattern of fungal hyphae belonging toPseudospiropessp. The fungus colonizes branches or seedlings during their first season, and the density of its coverage increases every year thereafter. The fungus was absent from striped maple at a site near Lake Placid, NY, and there is some evidence that its frequency of occurrence has declined elsewhere in the last few years. A pure culture of the fungus was unable to hydrolyze several plant cell wall polymers. It was able to use simple lipids, however, and its presence increased the erosion of the cutinized layer of striped maple stems. The fungus does not penetrate the stem surface, and its occurrence is not correlated with twig length or volume. It was absent from three sympatric maple species.

ISSN:0008-4026    

DOI:10.1139/b88-235

出版商:NRC Research Press    

年代:1988

数据来源: NRC

摘要:

Eight winter wheat, one triticale, and three fall rye cultivars with mean lethal temperature (LT50) values from −5.5 to −20.0 °C were harvested in late November and analyzed for fructans. Fructose, sucrose, and oligofructans with a degree of polymerization (DP) of 6 or lower were found in all cultivars. The concentration of DP 4 fructan was higher than that of DP 5 in winter wheat and triticale, while the opposite trend was found in fall rye. Fructans with a DP of 7 or higher (high DP fructans) were found at high concentrations in hardy winter wheat and fall rye. The high DP fructan was very low or negligible in the least hardy winter wheat cultivar 'Super X'. Fructans in winter cereals consisted mainly of inulin type with a β-2-1 linkage. The activity of phlein sucrase, which catalyzes synthesis of phlein, was much lower in winter cereals compared with phlein-rich grasses. It was concluded that high DP fructans of inulin type in basal top tissues of winter cereals were more closely associated with freezing resistance than low DP fructans.

ISSN:0008-4026    

DOI:10.1139/b88-236

出版商:NRC Research Press    

年代:1988

数据来源: NRC

摘要:

Early leaf development ofAdiantum capillus-venerisL. was examined with special reference to the origin of constituent cells of the leaf. At the earliest stage of leaf development, an enlarged superficial cell (leaf initial cell) occurs in the fourth or fifth cell packet derived from the shoot apical cell and divides to form a leaf apical cell. At the same time, cells surrounding the enlarged cell, which are not derivatives of it, also divide to form the basal part of a leaf primordium. Unlike the situation in leaves of other ferns, the leaf apical cell does not divide actively during early development, while the basal cells divide frequently from the beginning. The major part of a fairly developed leaf primordium therefore consists of derivatives of the basal cells. The leaf primordium is multicellular in origin in the sense that its distal part is derived from the enlarged superficial cell and its basal part from the cells surrounding the enlarged superficial cell.

ISSN:0008-4026    

DOI:10.1139/b88-237

出版商:NRC Research Press    

年代:1988

数据来源: NRC

摘要:

Eggplant (Solarium melongenaL.) cotyledons grown on Murashige and Skoog medium with naphthaleneacetic acid formed callus, roots, and somatic embryos. Low levels of naphthaleneacetic acid (0.1 – 0.5 mg L−1) favoored rhizogenesis, intermediate levels (1.0 – 5.0 mg L−1) favoured embryogenesis, and high levels (10 – 50 mg L−1) favoured callogenesis. Addition of polyamines or their precursors did not induce morphogenesis on medium containing no growth regulator, nor did it affect embryogenesis on medium containing naphthaleneacetic acid, except at the highest concentrations tested, which were inhibitory. Enzyme-activated inhibitors of putrescine synthesis significantly reduced embryogenesis and stimulated rhizogenesis. α-Difluoromethylornithine was more potent in inhibiting embryogenesis and stimulating rhizogenesis than was α-difluoromethylarginine. α-Difluoromethylarginine did not inhibit growth and α-difluoromethylornithine stimulated growth. Addition of putrescine with α-difluoromethylornithine restored embryogenesis to control levels and reduced rhizogenesis. Competitive inhibitors of polyamine synthesis had nonspecific effects. Compared with seedling cotyledons, expiants grown on 5.0 mg naphthaleneacetic acid per litre contained slightly less free soluble putrescine and about the same amount of spermidine. At day 8, free putrescine and spermidine levels were higher in explants grown on naphthaleneacetic acid than in those grown on medium containing no growth regulator. Addition of α-difluoromethylornithine greatly reduced the putrescine and spermidine titres of the explants. Application of putrescine with α-difluoromethylornithine dramatically increased putrescine titres but not spermidine titres. Although the results suggest a role for polyamines in eggplant somatic embryogenesis, they do not support the hypothesis that polyamines act as auxin- or cytokinin-like growth regulators or as second messengers for auxin in this system.

ISSN:0008-4026    

DOI:10.1139/b88-238

出版商:NRC Research Press    

年代:1988

数据来源: NRC

摘要:

The ultrastructure of ascosporogenesis inGyromitra esculenta(Pers.) Fr. is examined and compared with that reported for other Pezizales. Observations are made on spore delimitation, primary wall deposition, and formation of the secondary wall. Primary wall formation is similar to that reported for other species of Pezizales. The more or less smooth, electron-dense secondary wall appears to be derived from loose, fibrillar material of the perisporal sac. Observations are also made on structure and origin of the epispore and on cytological details of the epiplasm and sporoplasm relating to spore ontogeny.

ISSN:0008-4026    

DOI:10.1139/b88-239

出版商:NRC Research Press    

年代:1988

数据来源: NRC

摘要:

Polypeptides from 5% CO2adapted and air-adapted cells ofChlamydomonas segnis, extracted in the presence of the zwitterionic (ampholytic) detergent CHAPS, then lyophilized and washed with a chloroform – methanol mixture, were compared with those extracted in the presence of sodium dodecyl sulphate and Nonidet-P40 and precipitated by cold acetone, using two-dimensional electrophoresis. The electrophoretograms of these detergent-soluble polypeptides indicate that the use of CHAPS instead of sodium dodecyl sulphate – Nonidet-P40 considerably increases the mobility of proteins in the isoelectric focussing gels, improves resolution, and facilitates the detection of polypeptides with low molecular masses on the gradient gels. Comparison of polypeptides extracted with CHAPS from air-adapted and 5% CO2adapted cells revealed the presence of 20 polypeptides unique to the former type of cells. Fourteen of these polypeptides had molecular masses of approximately 20 kDa and isoelectric-point (pI) values ranging from 7.4 to 6.4. They represented the major proteins characteristic of cells capable of active photosynthesis and growth under atmospheric concentrations of CO2.

ISSN:0008-4026    

DOI:10.1139/b88-240

出版商:NRC Research Press    

年代:1988

数据来源: NRC