摘要:

Aluminum-induced inhibition of root growth in the Al-sensitive cultivar Kearney of barley (Hordeum vulgareL.) is the result of disruption of both cell division in the meristematic region and cell expansion in the zone of elongation of the roots. In seedlings directly germinated in 50 μM Al, inhibition of root growth is detected 48 h after initiation of germination and it results primarily from the disruption of cell elongation. In seedlings germinated for 2 days under Al-free conditions, inhibition of root growth is apparent 8 h after transfer to 50 μM Al. In this instance, root growth inhibition is mainly the result of disruption of cell division in the meristematic region of the root. The calcium indicator dyes chlorotetracycline and Fluo-3 are used to study the distribution of intracellular calcium and its relationship to aluminum phototoxicity. Aluminum increases both chlorotetracycline and Fluo-3 fluorescence intensities. Fluorescence of the cytosolic calcium indicator dye Fluo-3 increases primarily in the zone of elongation of the roots of seedlings directly germinated in 50 μM aluminum. The increase in Fluo-3 fluorescence occurs concomitantly with major changes in both the length and width of the cells in the zone of elongation. The evidence suggests that changes in calcium homeostasis occurring in cells of the zone of elongation may be a major factor in the disruption of cell expansion and consequently root growth in seedlings directly germinated in 50 μM aluminum.Key words: aluminum, calcium, barley, chlorotetracycline, Fluo-3.

ISSN:0008-4026    

DOI:10.1139/b95-197

出版商:NRC Research Press    

年代:1995

数据来源: NRC

摘要:

Growth, morphology, and anatomy were examined in cultivated barley (Hordeum vulgareL. cv. Harrington), and wild barley (Hordeum jubatumL.) collected from a wild population located in Saskatoon, Sask. Plants were grown in nutrient solution plus mixed sulphate salts with low or high calcium supply and in nutrient solution alone (control), using a hydroponic system in a growth chamber. Salt stress had greater deleterious effects on growth, morphology, and anatomy of 'Harrington' than wild barley. Additional Ca supply markedly improved these parameters in 'Harrington' but not in wild barley, suggesting a greater responsiveness to Ca in the cultivated species. The wild barley population had greater leaf and tiller numbers per plant but smaller leaf area and dry mass than 'Harrington' in control solution. After 20 days of salt treatment, 'Harrington' showed a greater reduction in tiller and leaf number, shoot height and root length, and tissue dry mass than wild barley. Calcium-deficiency symptoms were found in 'Harrington' leaves in the low Ca salt treatment but not in wild barley. On the other hand, shoot height and dry mass growth were significantly increased in 'Harrington' by high Ca salt treatment, suggesting that 'Harrington' was more responsive to supplemental Ca than wild barley. Salt stress induced thicker roots with larger vessels in 'Harrington' but not in the wild barley population.Key words: calcium nutrition,Hordeum vulgareL.,Hordeum jubatumL., hydraulic resistance, salt tolerance, root anatomy, sulphate salinity.

ISSN:0008-4026    

DOI:10.1139/b95-198

出版商:NRC Research Press    

年代:1995

数据来源: NRC

摘要:

A light microscope study of the initiation of the frond and sporangial development inSchizaea pectinatarevealed that sporangia arose from single-celled initials in marginal positions on narrow, strap-shaped pinnae. The sporangia were displaced to a superficial position by marginal development of a false indusial (pseudoindusial) structure. Divisions of a single, central initial with four cutting faces produced the archesporial tissue and a two-layered tapetum that differentiated into a combination tapetum consisting of an outer, cellular parietal tapetum and an inner, plasmodial tapetum that was intimately associated with the archesporial tissue and later with the developing spores. Mature sporangia had an apical annulus consisting mainly of a single tier of cells that differentiated from the layer of cells forming the sporangium wall. Thirty-two spore mother cells were produced and if no abortion occurred, approximately 128 spores developed within each sporangium.Key words:Schizaea pectinata, sporangial ontogeny, parietal tapetum, plasmodial tapetum, combination tapetum.

ISSN:0008-4026    

DOI:10.1139/b95-199

出版商:NRC Research Press    

年代:1995

数据来源: NRC

摘要:

Evolution of the exothermic profile of latent buds ofVitis viniferaL. cv. Pinot noir was followed using differential scanning microcalorimetry. Analyses performed on buds at the winterized state (stage 1), on wolly buds (stage 3), and on green pointing buds (stage 5) showed that modes and speed of extracellular and intracellular liquid crystallisation vary according to the phenological stage and are closely linked to the meristematic tissues. Among these, the vascular system plays a major role in the crystallisation process. Indeed, within the winterized buds, where it is at the procambial stage, i.e. nonfunctional, it forms a barrier to the propagation of ice toward the apical part of the bud where water remains in a prolongated surfusion state. On the opposite, during the period preceeding bud opening, from stage 3 to stage 5, where its differentiation leads to a continuous and functional vascular system connecting the bud base to its apical part, it forms a preferred path allowing rapid ice propagation, leading to a violent ice setting in all the tissues.Key words: latent bud, exotherm, calorimetry, vascular system, wine. [Journal translation]

ISSN:0008-4026    

DOI:10.1139/b95-200

出版商:NRC Research Press    

年代:1995

数据来源: NRC

摘要:

3-Dimethylsulfoniopropionate (DMSP) is an osmoprotectant compound that serves as the biogenic precursor of dimethyl sulfide (DMS), an important atmospheric sulfur gas. DMSP is known to be accumulated by many marine algae but has been little studied in higher plants; it has previously been identified in only four angiosperm genera (one genus from the Asteraceae and three from the Poaceae), at levels of about 5 to 30 μmol g−1fresh weight. Leaves of 177 species of angiosperms representing 90 families from 55 orders were screened for DMSP. An indirect assay was used in which DMSP treated with a cold NaOH solution released acrylic acid and DMS, the latter being analyzed by gas chromatography. The detection limit was 0.01 μmol g−1fresh weight. Twenty-nine species (from 22 families and 22 orders) had detectable levels of DMSP, all fairly low (≤ 1 μmol g−1fresh weight). In vivo radiotracer labeling results indicated that species from the Asteraceae, Poaceae, and Rosaceae containing DMSP synthesize it from methionine viaS-methylmethionine, and that this pathway may be present at a low level in species of Asteraceae that do not accumulate detectable amounts of DMSP. Taken together, these data imply that the capacity for DMSP production is widespread among Angiosperms.Key words: 3-dimethylsulfonioproprionate,S-methylmethionine, dimethyl sulfide.

ISSN:0008-4026    

DOI:10.1139/b95-201

出版商:NRC Research Press    

年代:1995

数据来源: NRC

摘要:

Seven varieties of post-harvest apple (Malus domesticaBorkh.) fruit, i.e., Spartan, McIntosh, Newtown, Royal Gala, Jonagold, Red Delicious, and Golden Delicious, were examined for the presence and location of condensed tannins in the peel, pulp, and seeds. Statistically significant differences in the condensed tannin content were found between varieties and sources, and in different tissues within a variety. Red Delicious had the greatest amount of condensed tannin in the peel and pulp, whereas Golden Delicious had the least. The amount in the seed was low and variable. Light and electron microscopy revealed tannins in the hypodermal layers of the peel, near the floral bundles in the cortex of the pulp, and in the thick-walled sclerenchyma and crushed parenchyma of the testa. The condensed tannin deposits in the peel appeared most concentrated in the hypodermal cell layer adjacent to the epidermis, with lesser amounts in cell layers closer to the cortex. Electron micrographs revealed that condensed tannin deposits were always found in the vacuole, taking different forms, and mainly associated with the tonoplast.Key words: condensed tannins, apple, peel, pulp, seed, vanillin–HCl, microscopy.

ISSN:0008-4026    

DOI:10.1139/b95-202

出版商:NRC Research Press    

年代:1995

数据来源: NRC

摘要:

The taxonomy and phylogenetic relationships of the fungal genusFimetariella(Ascomycotina, Lasiosphaeriaceae) are discussed. A revised generic description and key are presented. Descriptions and illustrations are provided for all taxa.Fimetariella dunarumn.comb. andFimetariella apotoma, Fimetariella brachycaulina, Fimetariella dolichopoda, Fimetariella macromischa, Fimetariella microsperma, andFimetariella tetrasporan.spp. are proposed. A phialidic anamorph resemblingCladorrhinumis reported forF.microsperma. The ascospores of the type speciesFimetariella rabenhorstiiare considered to possess two terminal germ pores, one large pore and one very small pore, along with several small, apparently nonfunctional pores. A key to the genera with these minor pores is included.Key words:Fimetariella,Cladorrhinum, coprophilous, fungi, keys, taxonomy.

ISSN:0008-4026    

DOI:10.1139/b95-203

出版商:NRC Research Press    

年代:1995

数据来源: NRC

摘要:

Mixed mating strategies in plants, such as chasmogamy and cleistogamy, may have evolved to optimize reproductive response to local, often variable, environmental conditions. A 2-year field experiment was conducted to examine the effects of light and nutrient availability on growth and chasmogamous and cleistogamous flower and fruit production inViola mirabilis, a perennial forest understory herb. Using a factorial design, we examined whether the mode of reproduction or reproductive output ofV.mirabiliswould be influenced by a repeated fertilizer application and (or) gradual shading with artificial plants. In this population ofV.mirabilis, the predominant mode of reproduction during both study years was chasmogamy. In the 2nd year of study, the number of both chasmogamous and cleistogamous flowers per plant decreased with decreasing light intensity, while the increased nutrient supply had no effect on flower or fruit production or plant growth. In addition, the proportion of cleistogamous flowers was smaller for shaded plants. However, the change in the proportion of cleistogamous or chasmogamous flowers from 1993 to 1994 was not affected by shading or fertilization. The production of cleistogamous flowers correlated positively with final total leaf area during both study years, while no correlation was found between the number of chasmogamous flowers and leaf area. In most studies, chasmogamy has been found to be dependent on plant size and favourable environmental conditions, whereas cleistogamy is generally considered to be relatively independent of these factors. However, our results suggest that only plants reaching a large size were capable of producing cleistogamous flowers in addition to chasmogamous flowers produced earlier in the season. Also, it seems that the general assumption of cleistogamic reproduction as a more advantageous mode of reproduction in poor light conditions compared with chasmogamy does not apply toV.mirabilis.Key words: chasmogamy, cleistogamy, light, nutrients, reproductive success,Viola mirabilis.

ISSN:0008-4026    

DOI:10.1139/b95-204

出版商:NRC Research Press    

年代:1995

数据来源: NRC

摘要:

Agaricus bisporusis known from field collections in several parts of southern Canada and the border states of Washington and Idaho. In Ontario, the species is associated with urban horticultural sites, agricultural areas, and thoroughfares. In British Columbia, Washington, and Idaho, the species is less well documented but occurs in habitats similar to those in Ontario. All studied isolates from these two regions were genotypically similar to those collected in Europe and also to a representative sample of cultivar isolates believed to be of European origin. In contrast, a population from forests ofPiceain the Rocky Mountains of Alberta had genotypes that are very different from European and cultivar groups, including the putatively introduced populations in other parts of Canada. To a lesser extent, the Albertan individuals also differed from three other isolated natural populations, two in California and one in Israel. Two of 35 isolates from Alberta had nuclear genotypes that were partially or entirely consistent with European ancestry, indicating that foreign (probably cultivar) germ plasm has become established in the native habitat. Thirty of 35 isolates from the Alberta field sample had one of six mitochondrial DNA (mtDNA) haplotypes known only from Alberta; the remaining five had an mtDNA type known from cultivar strains. However, nuclear genotypic similarity to other Albertan or European-cultivar isolates was not significantly correlated with presence or absence of this latter mtDNA type. The genetic diversity represented by the previously unknown Albertan population, and to a lesser extent by the heirloom varietal lineages and their derivatives that have become established in Ontario, British Columbia, Washington, and Idaho, is an important resource for breeders of this valuable fungal crop species. Threats to resource populations of this species, and possible responses, are discussed.Key words:Agaricus bisporus, mushroom population biology, resource management, germ plasm conservation, genetic diversity, microphylogeny.

ISSN:0008-4026    

DOI:10.1139/b95-205

出版商:NRC Research Press    

年代:1995

数据来源: NRC

摘要:

Amino acid pools and enzyme activities of NH3-assimilation (glutamine synthetase, glutamate synthase), proline biosynthesis (pyrroline-5-carboxylate reductase), proline catabolism (proline dehydrogenase, proline oxidase), and ornithine transamination (ornithine transaminase) were determined in control and salinized (140 mM NaCl) calli from tomato roots. Three populations were used: the domestic salt-sensitiveLycopersicon esculentumMill. cv. P-73, the wild salt-tolerantLycopersicon pennellii(Correll) D'Arcy, accession PE-47, and their F1interspecific cross, for which the relative growth rate on salt media was intermediate to those of the parents. Compared with control conditions, proline levels increased with NaCl treatments by twofold, threefold, and sixfold in the wild species, the F1hybrid, and the domestic species, respectively. This proline accumulation in the F1and the domestic populations was not modulated by changes in the enzyme activities of proline biosynthesis or catabolism. NaCl tolerance, amino acid (proline, alanine, arginine, asparagine) content, and velocity of enzymes responsible for proline biosynthesis and catabolism are dependent on explant sources (cotyledon, root) from which the F1calli were derived. The comparison of proline (PRO) responses in the different calli and populations indicated (i) various changes in anabolic or catabolic rates of PRO metabolism for a given range of PRO accumulation and (ii) the presence in the F1of both wild and sensitive parent characters in growth and PRO responses.Key words: callus culture,Lycopersicon esculentum,Lycopersicon pennellii, F1tomato, proline synthesis, proline catabolism, salt stress.

ISSN:0008-4026    

DOI:10.1139/b95-206

出版商:NRC Research Press    

年代:1995

数据来源: NRC