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Pascal Ginisty Bernard Besnainou Claire Sahut Jean Guezennec 《Biotechnology letters》1998,20(11):1035-1039
The influence of different cationic pretreatments of biomass (2000 meq cations/g biomass) on the biosorption of cobalt on Pseudomonas halodenitrificans was investigated. Li was the least inhibitory of Co2 biosorption (0.64 meq/g) and divalent ions were the most inhibitory (0.56 meq/g with Ca2, 0.46 meq/g with Mg2). Nevertheless, the binding between monovalent ions and biomass was too weak to study the role of ion-exchange in the mechanism of biosorption. A stoichiometric exchange occurred between Ca2 and 1 mM Co2 or less. © Rapid Science Ltd. 1998 相似文献
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Leaf chlorosis in oilseed rape plants (Brassica napus) grown on cadmium-polluted soil: causes and consequences for photosynthesis and growth 总被引:11,自引:0,他引:11
Brassica napus L. (oilseed rape) was grown from seeds on a reconstituted soil contaminated with cadmium (100 mg Cd kg−1 dry soil), resulting in a marked chlorosis of the leaves which was investigated using a combination of biochemical, biophysical
and physiological methods. Spectroscopic and chromatographic analyses of the photosynthetic pigments indicated that chlorosis
was not due to a direct interaction of Cd with the chlorophyll biosynthesis pathway. In addition, mineral deficiency and oxidative
stress were apparently not involved in the pigment loss. Leaf chlorosis was attributable to a marked decrease in the chloroplast
density caused by a reduction in the number of chloroplasts per cell and a change in cell size, suggesting that Cd interfered
with chloroplast replication and cell division. Relatively little Cd was found in the chloroplasts and the properties of the
photosynthetic apparatus (electron transport, protein composition, chlorophyll antenna size, chloroplast ultrastructure) were
not affected appreciably in plants grown on Cd-polluted soil. Depth profiling of photosynthetic pigments by phase-resolved
photoacoustic spectroscopy revealed that the Cd-induced decrease in pigment content was very pronounced at the leaf surface
(stomatal guard cells) compared to the leaf interior (mesophyll). This observation was consistent with light transmission
and fluorescence microscopy analyses, which revealed that stomata density in the epidermis was noticeably reduced in Cd-exposed
leaves. Concomitantly, the stomatal conductance estimated from gas-exchange measurements was strongly reduced with Cd. When
plants were grown in a high-CO2 atmosphere (4,000 μl CO2 l−1), the inhibitory effect of Cd on growth was not cancelled, suggesting that the reduced availability of CO2 at the chloroplast level associated with the low stomatal conductance was not the main component of Cd toxicity in oilseed
rape.
Received: 14 July 2000 / Accepted: 27 August 2000 相似文献
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Julia Bechteler Gabriel Peñaloza-Bojacá David Bell J. Gordon Burleigh Stuart F. McDaniel E. Christine Davis Emily B. Sessa Alexander Bippus D. Christine Cargill Sahut Chantanoarrapint Isabel Draper Lorena Endara Laura L. Forrest Ricardo Garilleti Sean W. Graham Sanna Huttunen Javier Jauregui Lazo Francisco Lara Juan Larraín Lily R. Lewis David G. Long Dietmar Quandt Karen Renzaglia Alfons Schäfer-Verwimp Gaik Ee Lee Adriel M. Sierra Matt von Konrat Charles E. Zartman Marta Regina Pereira Bernard Goffinet Juan Carlos Villarreal A. 《American journal of botany》2023,110(11):e16249
Premise
Bryophytes form a major component of terrestrial plant biomass, structuring ecological communities in all biomes. Our understanding of the evolutionary history of hornworts, liverworts, and mosses has been significantly reshaped by inferences from molecular data, which have highlighted extensive homoplasy in various traits and repeated bursts of diversification. However, the timing of key events in the phylogeny, patterns, and processes of diversification across bryophytes remain unclear.Methods
Using the GoFlag probe set, we sequenced 405 exons representing 228 nuclear genes for 531 species from 52 of the 54 orders of bryophytes. We inferred the species phylogeny from gene tree analyses using concatenated and coalescence approaches, assessed gene conflict, and estimated the timing of divergences based on 29 fossil calibrations.Results
The phylogeny resolves many relationships across the bryophytes, enabling us to resurrect five liverwort orders and recognize three more and propose 10 new orders of mosses. Most orders originated in the Jurassic and diversified in the Cretaceous or later. The phylogenomic data also highlight topological conflict in parts of the tree, suggesting complex processes of diversification that cannot be adequately captured in a single gene-tree topology.Conclusions
We sampled hundreds of loci across a broad phylogenetic spectrum spanning at least 450 Ma of evolution; these data resolved many of the critical nodes of the diversification of bryophytes. The data also highlight the need to explore the mechanisms underlying the phylogenetic ambiguity at specific nodes. The phylogenomic data provide an expandable framework toward reconstructing a comprehensive phylogeny of this important group of plants. 相似文献7.
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