ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1991.tb00186.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1991.tb00187.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractIn this and three further papers 205 yeasts and yeast states of Basidiomycetes and presumed relatives were investigated comparatively on the basis of the carbohydrate (neutral sugars) pattern of purified cell walls, urease‐activity, diazonium blue B reaction on the production of extracellular amyloid compounds (EAS), fermentation of carbohydrates, and ubiquinone data. A clustering leading to theProtomyces‐, theMicrobotryum‐, theUstilago‐, theDacrymyces‐, and theTremella‐type became apparent, especially from the qualitative and quantitative cell wall carbohydrate pattern.The different yeast types correspond well with 5S rRNA clusters known from the literature. 31 strains clustering within theMicrobotryum‐type comprise the phragmobasidial smut fungi of dicotyledonous hosts (Microbotryum. Sphacelotheca), the phragmobasidialRhodosporidium‐ andLeucosporidium‐species including some anamorphRhodotorula‐species, which lack an oxidative degradation of myo‐inositol, the generaSporobolomycesandSporidiobolus, the Septobasidiales and some simple septate Auriculariales e.g.Agaricostilbum, Platygloea. Main characteristics of theMicrobotryum‐type are: 1. The absence of extracellular amyloid compounds. 2. The dominance of mannose and the presence of fucose as cell wall constituents. 3. A positive DBB‐reaction and splitting of urea. FourUstilagospecies parasitic on dicotyledonous hosts were transfered toMicrobotryum (M. scabiosae, M. scorzonerae, M. cordae, M. vinosum) as a consequence from cell wall carbohydrate composition, production of rhodotorulic acid, and 5S rRNA sequence data from the literature.The predominance of mannose in the cell wall — otherwise only known from ascomycetous yeasts –, a type A secondary structure of 5S rRNA, a simple unifactorial mating system in all parasitic smut species suggest that theMicrobotryum‐typemight be ancestral to theUstilago‐type. An evolution of simple (“siphonal”) holobasidia from “pseudotr

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1991.tb00188.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe occurrence and abundance of nickel‐resistant bacteria was studied in various soils originating from serpentine and other ultramafic rocks from both temperate and tropical localities. Samples were taken from soil covered with herbs and shrubs not known to accumulate nickel and from areas inhabited by nickel‐hyperaccumulating shrubs and trees. In samples taken from the humus and mineral soil layers underneath the canopy of nickel‐hyperaccumulating trees, the number of bacteria able to grow at 3, 10 and 20 mM NiCl2, was almost as high as the number of bacteria growing in the absence of nickel ions. In contrast, for soil samples taken outside these areas only moderately nickel‐resistant (3 mM NiCl2) bacteria and low numbers were encountered. It is concluded that, in humid climate zones, the predominance of nickel‐resistant bacteria in the soil is not due to the nickel ions generated by the weathering of nickel‐containing rocks but is due to nickel salts being continuously liberated by the decay of nickel‐rich leaf litter. Nickel‐hyperaccumulating plants can be considered to drive a nickel cycle resulting in the continuous percolation of the top soil

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1991.tb00189.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractFortyEctocarpus siliculosusisolates from a wide geographical range, including gametophyte and sporophyte plants, have all been acclimated to the same salinity for several years. Their salinity tolerances in respect of cell viability, photosynthesis and dark respiration were evaluated over the salinity range: 8 to 96 ‰. Significant differences in the physiological tolerances to salt stress compared with viability measurements were evident. Genotypic differences in salt tolerances between groupings of the isolates, and also differences in responses of gametophyte and sporophyte generations were found. However, diploid and haploid sporophyte material had similar tolerances. Triploid and tetraploid sporophytes did not have improved tolerances over those of diploid plants. Culture plants originating from low salinities in the Baltic Sea had broader tolerances than field material collected from Baltic waters of similar salinit

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1991.tb00190.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractConcentrations of ions and sucrose in the vacuolar sap ofChara canescensgrowing in an oligohaline lake (1.5 ‰) were estimated over the main growth period of the plants. During fructification vacuolar sap contained a mean of 41 mol m−3(range 10.2–61.8) sucrose. The mean turgor pressure was 239 mosmol kg−1(range 219–264).In long‐ and short‐term experiments these plants were subjected to increasing salinities up to 22 ‰. When salinity was increased from 1.5 to 4.4 ‰ turgor pressure was restored to only 80 % of the initial value. This reduced level of turgor pressure was maintained up to a salinity of 22 ‰. The increase in vacuolar osmotic potential was due to the monovalent ions Na+, K+and Cl−. The relative amounts of Na+and K+participating in the regulation process were dependent on external salinity.The regulatory mechanisms observed in the brackish water speciesCh. canescensare compared with those reported from freshwater a

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1991.tb00191.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractWildAnanasspecies in northern South America occur in shady environments and appear to be relatively intolerant to droughts associated with growth under full sun exposure. This behaviour contrasts with the higher productivity of commercial varieties ofAnanas comosuswhen grown under full sun exposure. Such differentiation within the genus offers an opportunity to study the process of adaptation of apparently high light avoiding species into true sun plants. As a first approximation, the analysis of nitrogen content and carbon and hydrogen isotope ratios of bromeliads growing under natural conditions was undertaken to test the following hypotheses: 1. Leaf nitrogen content of plants grown under partial shade is higher than that of the same species in the same habitat growing under full sun exposure, due to the higher availability to nitrogen in the under‐canopy, but also to the lower proportion of structural carbohydrates in shade leaves; 2. δ13C values are usually more negative in CAM bromeliads growing under partial shade because of the lower contribution of CAM to total carbon gain, and the probable fixation of CO2originating from soil respiration; 3. δD values of CAM bromeliads are less negative than those of C3 bromeliads, but CAM bromeliads grown in shady habitats tend to have more negative δD values because of the lower relative accumulation of deuterium in leaf tissue water, and also because of their relatively lower CAM activity. The results show a clear differentiation between CAM and C3 bromeliads based on δ13C values, and in general δD values are less negative in CAM bromeliads. However, in several species overlapping δD values between C3 and CAM bromeliads were observed. The analysis of paired samples of the same species grown under contrasting light intensity usually conformed with the expectations. A number of deviations from the hypotheses were observed which appeared to be related to particular environmental conditions. The interpretation of δD values obtained from total organic matter is made difficult by the local variation of hydrogen/deuterium ratios in water available to t

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1991.tb00192.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe ultrastructure of mycoparasitic interactions in heterobasidiomycetes is diverse. A previously unknown cell structure, involved in a specific parasitic interaction, is described and illustrated. Cells of the parasitePlatygloea peniophorae(Auriculariales s.l., Basidiomycetes) which attach to host cells ofHyphoderma praetermissum(Aphyllophorales, Basidiomycetes) form distinct marginal vesicular bodies with electron‐opaque cores and electron transparent sheaths. Finally, the vesicular content projects through the cell wall of the parasite and then interacts with the cell wall of the host. Ontogenetic stages are described and illustrated in detai

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1991.tb00193.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe excretion of some sugars (maltose, glucose, and glucose‐6‐phosphate) was studied at pH 2.5–6.0 in 38 strains ofChlorellabelonging to 15 species of which 7 are capable and 8 incapable of symbiosis withHydra viridis. A high rate of maltose excretion below pH 4.0 (Cernichiari et al., 1969) was found only inC. vulgaris(non‐symbiotic) andC. mirabilis(non‐symbiotic). The otherChlorellaspecies are characterized by quite different patterns of sugar excretion.C. spec. (= “C. paramecii”;symbiotic) excretes very high amounts of maltose in the whole range from pH 2.5–6.0.C. kessleri(symbiotic),C. luteoviridis(symbiotic), andC. fuscavar.fusca(non‐symbiotic) show a predominant excretion of glucose‐6‐phosphate from pH 2.5–6.0. Some strains also exhibit a high excretion of glucose above pH 4.0 (C. spec. = “C. paramecii”) or below pH 3.0 (C. fuscavar.vacuolata). Several species, e.g.C. saccharophilavar.saccharophila(symbiotic),C. sorokiniana(non‐symbiotic), andC. protothecoides(symbiotic), excrete only very small amounts of sugars. There is no obvious correlation between sugar excretion and the ability or inability of theChlorellaspecies to form stabl

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1991.tb00194.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractPlant regeneration via organogenesis and embryogenesis was obtained from callus cultures ofChamaecytisus purpureusandChamaecytisus austriacus. While 2,4‐D (4 or 0.5 mg/l) proved highly efficient for callus induction, a combination of 0.1 mg/l IBA and 10 mg/1 BAP induced a high frequency of shoots from the calli. It is shown that, beside the growth factors, the composition of the basal medium represents a critical factor for regeneration. With increasing culture age, a strong reduction of the differentiation capacity was observe

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1991.tb00195.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY