摘要:

The physiological attributes of yeast communities associated with trees from one gymnosperm and nine angiosperm families were examined in comparison with contemporary classifications of the tree taxa. While the relationships between yeasts found in five coniferous genera (Pinaceae) did not show much congruence with chemotaxonomic or immunological classifications, a physiological classification of yeast communities from 19 genera of Angisoperms showed some compatibility with their respective assignments to families. Clustering of trees as yeast habitats at the family and higher levels indicated that the physiological profiles of yeast communities are to some degree correlated with the taxonomic position of the tree taxa as viewed by some authors. The yeast communities associated with certain tree families appeared nutritionally specialized as compared to others. This evolutionary specialization most likely operates by selection of physiologically limited yeasts, rather than by reduction of the number of yeast species in each community.

ISSN:0008-4026    

DOI:10.1139/b82-038

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

A review of the history of palynology and its usefulness in biosystematics, taxonomy, geology, and allergology is presented. In addition, its application to the taxonomic study ofPlantago, Trifolium, Tamarix, Clarkia, andSuaedaas used by the staff at Agriculture Canada is summarized. Scanning electron photomicrographs and light photomicrographs representing segments of these studies are included.

ISSN:0008-4026    

DOI:10.1139/b82-039

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

The effect of abscisic acid (ABA) and the cytokinins benzyladenine (BA) and kinetin on the cold hardiness of winter wheat (Triticum aestivumL.) was investigated by controlled freeze tests. ABA or BA applied as a foliar spray to nonacclimated plants or to plants acclimated for 1 week had no measurable effect on crown cold hardiness. The crown water content of winter wheat plants grown in nutrient solution supplemented with BA or kinetin decreased by twofold but cold hardiness was not increased. Thus, a reduction in water content alone does not necessarily result in increased cold hardiness. After 7 days of hardening ABA added with BA increased cold hardiness of crowns 3 to 4 °C depending upon the treatment.

ISSN:0008-4026    

DOI:10.1139/b82-040

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

Three new Laboulbeniales occurring on Carabidae (ground beetles) are described:Laboulbenia sciakyi, parasitic onPlanetes elegansNietner (Galeritinae, Planetini) from Sri Lanka,Rhachomyces basilewskyi, parasitic onEunostus burgeoniAlluaud (Galeritinae, Galeritini) from Zaire, andRhachomyces leleupidiae, parasitic onLeleupidia kahuzianaBasilewsky (Zuphiinae, Leleupidiini) from Zaïre.

ISSN:0008-4026    

DOI:10.1139/b82-041

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

Botanists pay too little attention to the importance of plants to mankind, including the relation of plants to human health. Many plant products available to the public are capable of causing serious harm to consumers. These include products which can produce allergic reactions in previously sensitized individuals, preparations which cause gastroenteritis but which are dispensed as herb teas, expectorants, or cathartics, abortifacients, and products with cardiovascular involvements. A further problem arises from the misidentification of plant products and from the contamination of harmless or beneficial plant material with toxic species. On the other hand, there are excellent possibilities for the discovery of new beneficial plant derivatives as illustrated by the recent development of vincristine and vinblastine from periwinkle for the treatment of leukemia and lymphoma.

ISSN:0008-4026    

DOI:10.1139/b82-042

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

The relationship between quantity of epicuticular wax and plant sensitivity to hydrogen chloride (HCl) gas was investigated using 8-, 12-, and 16-day-oldPhaseolus vulgarisL. plants exposed for 20 min to 27.6 ± 3.9 mg HCl∙m−3. Twelve-day-old plants were more sensitive than 8- or 16-day-old plants and possessed the lowest mean surface wax quantity. Multiple regression analysis showed that surface wax quantity was negatively linearly related to percent of leaves glazed. Necrotic injury was also negatively correlated with surface wax quantity, but to a lesser degree than glazing. Chamber temperature also affected the amount of necrotic injury incurred. Plant age and HCl concentration did not contribute to the observed variation in any of the injury variables in the regression analysis.The results of this study support the hypothesis that cuticular resistance, which is influenced by the amount of epicuticular wax, is a major factor influencing leaf glazing due to gaseous HCl. Since necrotic injury was affected by both surface wax quantity and chamber temperature, the incidence and severity of necrotic injury may be controlled by both cuticular and stomatal resistance

ISSN:0008-4026    

DOI:10.1139/b82-043

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

The effects of photoperiod and temperature on flower initiation and the rate of node production in a New Guinea hybridImpatienscv. Starburst were investigated. The node of first flower initiation was not a reliable estimate of the time of flower initiation unless treatment influences on the rate of node production were also considered. Plants maintained at 25 °C responded as quantitative short-day plants; the time of flower initiation was earlier, and the degree of flowering was greater, in 8- and 14-h photoperiods than in 18-h photoperiods. In short (12-h) photoperiods flowering was modulated by temperature. The time of flower initiation was reduced from 27 days at 25 °C to 13 days at 20 °C and to 10 days at 15 °C. Night-break experiments indicated that flowering at 25 °C was subject to photoperiodic control but at 15 °C the plants were "day-neutral."

ISSN:0008-4026    

DOI:10.1139/b82-044

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

The fluorescence microscope is one of the most sensitive instruments available for morphological and microchemical analysis of cereal grains. Recent innovations in illuminating systems, fluorescence chemistry, and specimen preparation methods have combined to provide dramatic improvements over conventional bright-field microscopy in both specificity and sensitivity. Examples of useful fluorescence methods for microscopic analysis of cereals are included.

ISSN:0008-4026    

DOI:10.1139/b82-045

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

Different isolates ofHelminthosporium teresproducein vitrophytotoxic compounds which diffuse in the culture medium. These compounds bring about the wilting of barley and tomato plants with roots removed. A semiquantitative estimation of toxin production, which was based on the inhibition of the growth of tomato seedlings, allowed the isolates to be classified according to their level of toxigenicity.The toxins, of variable thermostability according to strains, are not proteins and are not specific. The action of toxin filtrates on the leaf blade of a susceptible barley cultivar brings about the appearance of necrosis on the whole thickness of the leaf blade. There is a positive correlation between toxin production level of the isolates and necrogenic power of their filtrates.During the leaf-colonization stage, the primary action of the parasite on the surrounding cells seems to affect the plasmalemma which retracts from the cell wall and shows evaginations. In such cells, starch builds up and the size of the plastoglobuli is markedly increased in the chloroplasts. The limiting membrane of these chloroplasts is not affected.

ISSN:0008-4026    

DOI:10.1139/b82-046

出版商:NRC Research Press    

年代:1982

数据来源: NRC

摘要:

The pattern of geographic variation in the annual shoot production of the three bog shrubs (leatherleaf (Chamaedaphne calyculata), bog laurel (Kalmia polifolia), and Labrador tea (Ledum groenlandicum) was examined using data collected at eight peatland sites along an 800-km latitudinal transect. Productivity varied significantly among sites, withL. groenlandicumexhibiting the greatest range of values (114–505 mg/shoot), followed byK. polifolia(83–341) andC. calyculata(73–241). This variation could be best interpreted by including both climatic and substrate variables in a multiple regression equation. The combination of three site variables (heat sum, depth to standing water, and water conductivity) accounted for between 63 and 86% of the observed variation in shoot productivity. Adding four other variables increased the percentage of variation explained to between 95 and 99%.

ISSN:0008-4026    

DOI:10.1139/b82-047

出版商:NRC Research Press    

年代:1982

数据来源: NRC