摘要:

Thein vitrowood decay abilities ofGanoderma lucidum(W. Curt.: Fr.) Karst. andG. tsugaeMurr. were studied using the following woods in agar block decay chambers:Vitis viniferaL.,Quercus hypoleucoidesA. Camus,Prosopis velutinaWoot.,Abies concolor(Gord. & Glend.) Lindl. ex. Hildebr., andPseudotsuga menziesii(Mirb.) Franco. Grape wood lost the most weight while mesquite the least.Ganoderma lucidumisolates generally caused greater weight loss of all woods than didG. tsugaeisolates. The range of the percent weight losses varied with the wood. BothGanodermaspecies caused simultaneous decay in all woods. However, chemical analyses of the decayed blocks indicated that selective delignification by both species also occurred in grape and white fir blocks. Chemical analysis of the decayed oak blocks indicated the percentages of lignin and holocellulose were not statistically different from the controls. However, there was a trend towards delignification. The analyses of the Douglas-fir blocks indicated only simultaneous decay. Scanning electron microscopy demonstrated selective delignification and simultaneous decay of all woods tested. However, the extent of the delignification differed among the wood species. Delignification appeared mainly in areas of tracheids or fiber tracheids, while the rays were simultaneously decayed.

ISSN:0008-4026    

DOI:10.1139/b86-217

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

The vegetative and floral development of the hybrid grape cultivar ‘Ventura’ was studied. A tendril forms opposite the last-formed leaf on the shoot but is slightly delayed in its initiation. Six nodes and 10 primordia complete one leaf–tendril initiation cycle. The inflorescence develops at the same site and is initially indistinguishable from the tendril. Inflorescence primordia are initiated on the upper arm, first opposite each other in a decussate arrangement and then apparently spirally. Each inflorescence primordium may subsequently initiate two lateral primordia, which become subtended by bracts. These in turn may repeat the pattern so that ultimately third- or fourth-order cysmose inflorescence branches may be produced. During floral development the calyx is initiated at first as three primordia, followed by a ring, which ultimately develops five lobes. The five corolla primordia alternate with the sepals. The five stamen primordia are initiated opposite the petals. The gynoecium initiates as five primordia, which later become a ring. Two septae are initiated opposite each other on the inner flank of the ring, forming the two-loculed ovary. Each septum forms a placenta, giving rise to two ovules. The upper portion of the gynoecial ring grows up over the ovules and forms the short style and discoid stigma.

ISSN:0008-4026    

DOI:10.1139/b86-218

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

Life history and electrophoretic variation were examined in 39 populations ofAbutilon theophrastiL., velvetleaf, collected from southern Ohio (39° N) to central Ontario (45° N). These collections represent a climatic gradient at the northern extreme of the distribution range of this weed species in North America. Plants from each of the 39 populations were grown from seed in a standard garden trial. A total of 51 growth, germination, and morphological characters were measured for each population. Significant among-population differences (p < 0.05) were found for 33 of the 51 characters. Many of these population differences were correlated with latitude and climate. These patterns of variation may well represent the first stages of differentiation in response to local environment. Of particular importance was the wide range of differences among populations in proportions of seeds exhibiting dormancy. Results from an electrophoretic survey of 16 enzyme systems provided evidence for very low levels of allozyme variation among the 39 populations ofA. theophrasti. Only two enzymes were variable and only four multi-locus electrophoretic genotypes were evident among the 39 populations. Velvetleaf exhibited a number of genetic features characteristic of successful colonizers: high levels of fixed heterozygosity as a result of polyploidy, multilocus associations providing a reduced number of genotypes, and high levels of population differentiation in morphometric and life-history traits.

ISSN:0008-4026    

DOI:10.1139/b86-219

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

Explants of root, hypocotyl, cotyledon, stem, shoot tip, and leaf of seedlings obtained byin vitrogermination of seeds, as well as embryos excised from seeds, were utilized for the induction of callus. Murashige and Skoog basal medium supplemented with naphthaleneacetic acid (4 ppm), kinetin (2 ppm), and coconut water (15%) was found to be optimal for induction and growth of callus from all explants. Growth rate experiments were performed with callus to study the effect of different growth regulators at various concentrations. The calluses were heterogeneous in nature and consisted predominately of diploid cells, although a few polyploid cells were also observed after two and four subcultures. Plantlets, isolated roots, leaves, and shoots were differentiated in various callus cultures. The root tips and shoot tips of such plantlets revealed only diploid constitution. Embryolike structures were formed in callus on transfer to media containing naphthaleneacetic acid and 6-benzylaminopurine. Embryoid development was traced to a single cell which was invariably isolated from the rest of the callus tissue. This initial divided to form a multicelled structure which later gave rise to a globular, ovoid, or heart-shaped embryoid, or one with irregular form. The embryoids germinated into complete plantlets with root and shoot. The embryoidal initials were mostly diploid but occasional aneuploids or polyploids were observed.

ISSN:0008-4026    

DOI:10.1139/b86-220

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

Variation in needle and twig anatomy for 46 populations ofPseudotsuga menziesiiwas apportioned into that due to (i) taxonomic structure (the varietymenziesiifrom coastal areas, the varietyglaucafrom east of the Cascade crest, and intermediates from intervening areas); (ii) populations; and (iii) individual trees within populations. The variation was classified on the basis of summary variables, the principal components resulting from principal components analysis. Principal components analysis was performed both on original needle and twig variables and on residuals from multiple regression analysis of elevation, latitude, and longitude. The analysis of residuals removes the effect of allopatry and macroclimate. In both analyses, the smallest source of variation was taxonomic structure while most of the variation occurred within populations, suggesting that recognition of subspecific taxa in this portion of the geographic range is not appropriate. The results of analyses of original variables and residuals were highly correlated, indicating that relationships between individuals are not the result of allopatry or selection due to macroclimate. The observation that individuals account for most of the variation in the data is interpreted as indicating that the production of individual variants is a more significant evolutionary event than population differentiation.

ISSN:0008-4026    

DOI:10.1139/b86-221

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

The growth habits inCallisia fragransare studied in relation to the variation of simple morphological parameters such as the leaf area and the internode length and diameter. The architecture of this species being simple, as in many Monocotyledons, these parameters are the main morphological indicators for the different phases of the biological cycle. Five phases have been distinguished: the stolon, the establishment of the leafy stem, the indefinite growth of the leafy stem, the transition to flowering, and the final stage of flowering with the production of axillary flowers. The establishment of the leafy stem and the transition to flowering are two evolutionary phases while the others are stabilized. The quantitative study of the parameters shows that the stem diameter is always positively correlated to the leaf area while the internode length is negatively correlated to the leaf area mainly during the evolutionary phases. The internode lengthening coefficient, which expresses the internode shape, is negatively correlated to the leaf area. The correlations inC. fragransare compared to those observed in previous studies, and some general laws concerning the evolution of the morphological parameters are formulated.

ISSN:0008-4026    

DOI:10.1139/b86-222

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

Recent sand movement was inferred from grain morphology, modal grain size, and grain size distributional skewness of samples from the surfaces of beach–dune landscapes. Negative skewness indicated recent net deflation, and either positive skewness or small modal grain size indicated recent net aeolian accretion. Large grains that were shiny and angular indicated surfaces that could not have been deposited by wind. Net deflation occurred where vegetational cover was below 10%, in foredunes and an interdunal blowout. All other sites in dunal, interdunal, or forested zones showed evidence of net accretion or a balance of accretion and deflation. Net accretion was evident in locations with as little as 15% cover. Relationships between sand movement and vegetational composition could not be separated from relationships with total cover. The sandy foreland of one island was bulldozed during the 1950s. This apparently brought coarser Holocene beach deposits near the surface, which limited the severity of blowout by providing a deflation armor.Ammophila breviligulatahas not recolonized the interdunal zone of this island, though it persists in this zone on the other islands. The study of grains in cores may reveal the history of vegetational cover at a site.

ISSN:0008-4026    

DOI:10.1139/b86-223

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

Localization for polyphenol oxidase was carried out on 6-day-old etiolated soybean (Glycine max(L.) Merr.) tissue. Light and electron microscope observations of tissues exposed to the substrateL-dihydroxyphenylalanine after chemical fixation revealed that polyphenol oxidase activity was present in the lamellae and membrane-bound inclusions of chloroplasts. Inhibitors of polyphenol oxidase, diethyldithiocarbamate and phenylhydrazine, prevented formation of the reaction product. Only plastids in epidermal and associated cortex collenchyma cell layers contained inclusions and enzyme activity. Most guard cells and all cortex parenchyma cells were devoid of both. Homogenates of epidermal strips were shown to contain 95–99% of the total polyphenol oxidase activity present in hypocotyls.

ISSN:0008-4026    

DOI:10.1139/b86-224

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

The age structure was studied of two stands ofPinus sylvestrisL. andPicea abies(L.) Karst. growing on "fire-safe," opposing (north- and south-facing, respectively) slopes at the forest limit in the Scandes Mountains, in central Sweden. It is suggested that the spatial species segregation is due to different microclimatic demands during seedling establishment and early survival stages. Establishment of pine correlated positively with the mean "tetraterm" (June – September) air temperature over 20-year periods (1861 – 1980). A sequence of thermally favourable years appears to be important for population net growth at the forest limit. Establishment of spruce may relate to an absence of early summer drought, stable snow cover during the winter, and certain high-temperature demands for seed maturation. The extant pine population died off almost entirely during the climatic deterioration of the Little Ice Age (prior to A.D. 1700). From the mid-18th century onwards a new pine population was established, the seed parents being the few remaining survivors from the foregoing decimation. This process conforms broadly with the known pattern of climatic change. After the climax of the Little Ice Age spruce colonized new territory, a consequence of the summer warming combined with the still fairly humid conditions in early summer. No spruce established during the climax phase of warming during the 20th century (A.D. 1925 – 1940).

ISSN:0008-4026    

DOI:10.1139/b86-225

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

The degree of vesicular–arbuscular mycorrhizal root colonization of alpine fell-field plants was measured at six sites in the northern Rocky Mountains of Montana and Wyoming. Soils derived from calcareous or acidic crystalline parent materials were analyzed for chemical and physical properties and vesicular–arbuscular mycorrhizal fungal propagule density. Soils associated with calcareous parent materials had finer texture, higher pH, and higher levels of calcium, sodium, and silicon. Viable vesicular–arbuscular mycorrhizal propagule density was positively correlated with plant canopy cover. Typical vesicular–arbuscular mycorrhizal colonization occurred in 84% of the species examined. Vesicular–arbuscular mycorrhizal root colonization was significantly greater on soils derived from calcareous parent materials. Alkaline pH and high levels of calcium associated with calcareous soils may result in these soils being functionally more phosphorus deficient than are crystalline soils. Phosphorus deficiency may partially explain the higher levels of vesicular–arbuscular mycorrhizal colonization observed.

ISSN:0008-4026    

DOI:10.1139/b86-226

出版商:NRC Research Press    

年代:1986

数据来源: NRC