摘要:

AbstractThe bladders ofGeosiphon pyriforme, an endosymbiotic consortium of a fungus and the cyanobacteriumNostoc punctiforme, show nitrogenase activity. This suggests that the organism is capable of nitrogen fixation.

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1992.tb00309.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractUptake and desorption kinetics of methylglucose and pentachlorophenol (PCP) by needles ofPicea abies(L.) Karst. were studied. Uptake of methylglucose was very rapid, equilibrium was obtained within 2 h and the amounts of methylglucose associated with the needles could be completely desorbed within 8 h. In contrast, PCP uptake was steady for several hours and the amounts of PCP taken up could only partially be desorbed again. Needles treated with NaN3prior to uptake measurements, showed no methylglucose uptake at all, whereas PCP uptake was not affected. Thus it is concluded that the hydrophilic methylglucose was taken up solely by epiphytic microorganisms, whereas the lipophilic PCP was taken up into the needle interior in significant amounts. Consequences of these results on studies of foliar uptake of chemicals are pointed out.

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1992.tb00310.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe goal of the presented paper was to study the emission effects of natural air pollutants on the protein complexes of the thylakoid membrane. The tests were carried out in the frame of a long‐term experiment in which spruce trees kept in open‐top chambers with unfiltered ambient‐air were compared to spruce trees in chambers with purified‐air. The reaction centres of photosystem I (P‐700), cytochrome f, cytochrome b‐563, cytochrome b‐559, as well as the oxidation speed of the antennae chlorophylls were quantified.The concentrations of the cytochromes f and b‐563 indicate a marked annual rhythm with decreased concentrations during the summer months. The spruce trees in chambers with ambient‐air showed a smaller amount of the studied redox components in relation to 1000 molecules of chlorophyll than did the spruce trees in chambers exposed to purified‐air. In addition, increased oxidation speed of antennae chlorophylls could be observed on the isolated thylakoid membranes of the spruce trees in chambers with ambient‐air conditions. A relationship between the oxidation speed and the ozone concentration of the ambient air could be observed, i.e. with increasing ozone levels the oxidation of the antennae chlorophylls accelerated. However, the damage occurred only with a temporary delay (the so‐called memory effect).In case of the cytochromes f and b‐563 (components of the cytochrome b6f‐complex), a chamber effect related to changed light conditions became obvious when comparing spruce trees kept in chambers to trees left in their natural surrounding. The reduced photosynthetically active radiation — it is reduced in the chambers by 10 − 30% — led to a decrease of both cytochromes.In spite of the effects due to the chambers, the results indicate that ozone could be an effective damage factor and this will be of importance with regard to the situation in

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1992.tb00311.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractIn order to assess and compare the species‐specific mineral metabolism of various plants, we raised eight selected species from different families under identical nutritional conditions. Five different nutrient solutions with varying Ca/K ratios were used. After two months of growth, the leaves were harvested, arranged according to age, and analyzed with respect to their K, Ca, and Mg contents. The ion ratios, the changes of ion contents with increasing age, the differences in water‐ and acid‐soluble Ca (calcium oxalate), and the dependence of ion uptake on variations of ion concentrations in the solutions revealed a species‐specific (“physiotypic”) feature of mineral metabolism. These features are discussed taking into consideration the ecological demands of the investigated species, and assuming that the physiological peculiarities of a species should affect its ecologic

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1992.tb00312.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractParameters of light propagation in plant leaves — absorption and scattering coefficients, asymmetry of scattering — have been estimated on the basis of measured transmission and emission as well as internal fluxes. This estimation has been carried through by solving the inverse problem of the 4‐flux radiative transfer — a theory considering forward and backward diffuse as well as directed components of the overall radiation in a multiple scattering sample. Using the gained parameters, light flux gradients in a two‐layered model leaf have been calculated at different wavelengths. Monte Carlo simulation of absorption spectra performed with the parameters obtained with this treatment is in a good agreement with experimental spectra, thus substantiating the theory. Parallel calculations with the two‐flux (Kubelka‐Munk) theory provide an estimation of the accuracy and applicability of this more simple treatment. Calculations have been performed for three different plants:Catalpa bignonioides, Tilia americanaand

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1992.tb00313.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThein vitroandin vivophosphorylation of stomatal phosphoenolpyruvate carboxylase [EC 4.1. 1.31] fromVicia fabaL. was demonstrated by feeding the concentrated enzyme after 0–70% ammonium sulfate precipitation of guard cell protoplasts with32P and subsequent analysis of autoradiograms and Western immunoblots, after SDS‐PAGE, of protein samples. Thein vitroandin vivoresults provide evidence for a radioactive labeling of the two stomatal PEPCase bands (112 and 110 k

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1992.tb00314.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractA peroxidase which catalyzes, in essentially quantitative yield, the dimerization of jatrotthizine to 4,4′‐bisjatrorrhizine was isolated and partly characterized fromBerberis stoloniferacell cultures. This peroxidase also mediates the demethylation of a variety of 10‐ or 3‐O‐CH3substituted tetrahydroprotoberberines and their quarternary analogues. A survey of more than 30 cell culture species, using seven different alkaloids, demonstrated the presence of this catalytic activity mainly in the plant families Berberidaceae and Ranunculaceae, while it was absent in the Papaveraceae. Caution is justified when employing alkaloids labelled at their [‐O‐CH3] groups for enzymatic assays except when peroxidases (even without addition of H2O2) ar

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1992.tb00315.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractComplex‐heterozygotes discovered in populations ofO. grandiflorain Alabama are composed of a typical grandiflora (B) complex and an altered B complex which modifies the phenotype in the direction ofO. villosa(A). A cytogenetic analysis of the new complex, designated BA, is reported including results of its compatibility with different plastomes. The evidence suggests that the BAcomplex resulted from hybridization betweenO. grandifloraand the pollen complex of the sympatricO. bienni

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1992.tb00316.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe circadian rhythm in the oxygen production of 30 individualAcetabulariacells has been studied at different temperatures. The temperature induced period variation was continuously evaluated over the whole data record of each individual cell with an advanced spectral analysis technique. The observed circadian periods of O2production displayed a well established region of temperature compensation between 25 °C and 30 °C with a Q10, value of 0.9, whereas between 15°C and 22°C a positive temperature coefficient was measured (Q10at 22 °C 0.9, Q10at 20°C 0.8, Q10at 17°

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1992.tb00317.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractIn flowers ofHeliotropiums.l. the primary carpel tips are overtopped by commissural outgrowths. Therefore the stylar cleft mimics a lateral orientation of the carpels. In species in which the fruit splits into four diaspores the separation tissues run through both the median and the transverse fruit planes. In species where only two two‐seeded nutlets are developed the fruit splits within the false septa and each half is composed of parts of both carpels (“syn‐mericarp

ISSN:0932-8629    

DOI:10.1111/j.1438-8677.1992.tb00318.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY