摘要:

Two cultivars of tomato of Saint-Pierre phénotype, isogenic for the resistance against verticilliosis and different for the resistance against mildew (and againstPhytophthora parasiticaDast.), were inoculated withP.parasiticaand withVerticillium albo-atrumReinke et Berth. Associated with the defence reactions, an accumulation of sesquiterpenes phenolic compounds, tomatin, and oxygenated compounds of methyl linoleate took place in the tissues. Synthesis of these compounds in the host varies with the cultivars and the parasites in presence.In vitrostudies on the inhibition ofP.parasiticahave shown an important synergism between the dienols on one side and the phenolic compounds and tomatin on the other side. [Translated by the Journal]

ISSN:0008-4026    

DOI:10.1139/b86-131

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

Acetolyzed exines ofJuniperus communisextracted with hot 2-aminoethanol were prepared for electron microscopy. The strongly osmiophilic, homogeneous exine first becomes granular. With further extraction, granules are observed to surround unstained polygonal regions. The connections between granules are then broken leading to compound polygons, open polygons, and finally detached pieces. Orbicules and exine-1 are completely removed. The pattern of structural change is similar to that observed inLilium longiflorumand inFagus sylvatica.

ISSN:0008-4026    

DOI:10.1139/b86-132

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

Diurnal courses of gross CO2uptake and thallus water content of the lichenRamalina menziesiiTayl. were measured together with the environmental variables temperature, irradiance, and atmospheric humidity at a coastal and an inland site in central California. Twenty-three days, distributed over all seasons and a variety of weather conditions, were recorded at the inland site; 14 were recorded at the coastal site. Conditions in both habitats were similar in that the most frequent reason for photosynthetic inactivity inR.menziesiiwas insufficient thallus hydration. Irradiance was another factor controlling photosynthetic rates; temperature, on the other hand, had little influence. At the inland site, CO2fixation was concentrated in the rainy winter season and very little CO2fixation took place during the hot summers. In contrast, fog and high atmospheric humidity that frequently occur during summers at the coast provided sufficient moisture for frequent photosynthetic activity, thus resulting in intermittent activity throughout the year. While extremely high gross photosynthetic rates of up to 15 mg CO2 g−1thallus dry weight were measured at the inland site, rates at the coast were always much lower.

ISSN:0008-4026    

DOI:10.1139/b86-133

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

Histological analysis of developmental events during adventitious shoot formation in cultured epicotyl explants of black and white spruce was carried out. Cells towards the periphery of the expiants and between the bases of the cotyledons responded to cytokinin and became meristematic. Cell division in these regions led to the formation of meristemoids and ultimately intercotyledonary adventitious shoots. These shoots developed a vascular system, which became connected to the main vascular system of the expiant. After about a month of culture, the entire expiant became meristematic and showed evidence of additionalde novoshoot development. Several rings of bud primordia were found at the periphery of the expiant after about 40 days of culture. These primordia that developed in the subepidermal layers could easily be distinguished from the surrounding cells by their distinct boundaries and intense staining for nucleic acids and proteins. After 2 months of culture, the entire expiant was covered with well-developed shoots having organized apical meristems, needle primordia, and vascular systems.

ISSN:0008-4026    

DOI:10.1139/b86-134

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

The preparation and use of a strain-specific fluorescent antibody reagent is described for specific identification of a virulent strain ofFusarium vasinfectumAtk., in host tissues ofGossypium arboreum, var. K7 and in soil. Methods are discussed to eliminate autofluorescence of host tissues and soil.

ISSN:0008-4026    

DOI:10.1139/b86-135

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

Contrary to generalizations about differences in the adaptive significance of C3and C4photosynthesis,Stipa neomexicana, a C3grass, was restricted to the driest sites along a topographic and soil moisture gradient in a semiarid grassland in Arizona. The distribution ofStipa neomexicanawas inversely related to the abundance of C4grasses. The total biomass of C4grasses increased from low values on ridge crests to maximum values on lower, wetter sites. Ordination analysis confirmed that the topographic and soil moisture gradient was the factor most closely associated both with grass species distributions and with total biomass and cover. Other factors, such as soil fertility, did not appear to be closely related to vegetation patterns. The data suggest thatStipa neomexicanawas excluded from sites with greater soil moisture by competition with C4neighbors. While it is likely that other factors besides photosynthetic type determine the ability to survive on the driest sites in this system, C4photosynthesis appears to confer an advantage in competitive ability in microhabitats with greater amounts of soil moisture.

ISSN:0008-4026    

DOI:10.1139/b86-136

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

The concentrations of total nitrogen, of soluble and insoluble nitrogen, and of amino acids and free amides are always higher in tumors caused byEriosoma lanigerumHaussm. onPirus malusL. cv. Calville Blanc than in the controls. The highest concentrations are found in branches on the first days after their infestation by the aphid. Some of these compounds, such as asparagine and arginine, are notably present in the tumors and seem to be specific features of the tumoral state.

ISSN:0008-4026    

DOI:10.1139/b86-137

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

Prolonged exposure to blue light was necessary for almost complete inhibition of sporulation inAlternaria cichoriiNattrass. When a 24-h blue light exposure was followed by darkness, the inhibition of sporulation decreased gradually.

ISSN:0008-4026    

DOI:10.1139/b86-138

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

Soils were collected from eight different sites of saline marshy soils of Port Blair situated in the Andaman and Nicobar islands, India. A total of 93 333 colony-forming units representing 46 species of thermophilous fungi were isolated by the soil dilution method. The fungi were tabulated in order of ecological importance based on their frequency, relative density, and presence in the selected sites of this study. This is apparently the first study of these fungi from the Port Blair soils. Of the 46 species,Mucor miehei,Rhizopus oligosporus,Thermoascus crustaceous,T.thermophilus, andTrichoderma pseudokoningiiare new records for India andAcremonium terricola,Aspergillus acculeatus,A.nidulansvar.latus, andSporotrichum thermophileare isolated from Indian soils for the first time. The temperature responses of the fungi revealed 14 microthermophiles and 22 thermotolerant and 10 true thermophilic species. Thirteen species of thermophilous fungi have been reported in addition to those already recorded in the literature.

ISSN:0008-4026    

DOI:10.1139/b86-139

出版商:NRC Research Press    

年代:1986

数据来源: NRC

摘要:

Reciprocal factor analysis of data obtained from 70 stands in the Bois-de-Saraguay, points to drainage and succession – disturbance as the principal factors governing floristic composition. Successional vectors of the 11 most abundant tree species were also plotted on the ordination. The position of the vectors characterizes the species with regards to the two gradients which were identified. The shape of successional vectors allows the recognition of three classes. The first one includes those species showing an association pattern with other species, which hardly varies during the different growth phases. The second one groups together those with distinctly better reproduction in communities where they are scarce in the tree stratum. The third one regroups those which cannot maintain high densities in the intermediate strata of communities where they are common among trees and seedlings. However, further studies showed that the exact shape of the vectors is also related to abiotic variables, especially drainage modifications. A detailed analysis of these successional vectors allows a better understanding of what determines the occupancy of the study site by the species present. [Translated by the Journal]

ISSN:0008-4026    

DOI:10.1139/b86-140

出版商:NRC Research Press    

年代:1986

数据来源: NRC