نتایج جستجو برای: silicification
تعداد نتایج: 299 فیلتر نتایج به سال:
Plants take up silicon as mono-silicic acid, which is released to soil by the weathering of silicate minerals. Silicic acid can be taken up by plant roots passively or actively, and later it is deposited in its polymerized form as amorphous hydrated silica. Major silica depositions in grasses occur in root endodermis, leaf epidermal cells, and outer epidermal cells of inflorescence bracts. Deba...
A systematic model study on the role(s) of putrescine homologues on silicification is presented and it is proposed that electrostatic forces between additive and silicic acid, and the hydrophobic behaviour of the additives are both important in silicification.
Plants are significant exponents of biological silicification. While not all plants are generally considered as biosilicifiers the extent to which all plants deposit biogenic silica is largely unknown. There are plants which are known as silica accumulators though even in these plants the extent and degree to which their tissues are silicified is neither appreciated nor understood. An elucidati...
The preparation of hybrid materials from supramolecular polymers through the sol-gel process is presented. Supramolecular polymers are assembled from phosphodiester-linked pyrene oligomers and act as water-soluble one- or two-dimensional templates for silicification. The fibrillary and planar morphologies of the assemblies, as well as the excitonic interactions between the chromophores, remain ...
A series of experiments was made to determine the capacity of an archaeal strain, Methanocaldococcus jannaschii to bind metals and to study the effects of metal-binding on the subsequent silicification of the microorganisms. The results showed that M. jannaschii can rapidly bind several metal cations (Fe 3+ , Ca 2+ , Pb 2+ , Zn 2+ , Cu 2+ ). Considering the lack of silicification of this strain...
INTRODUCTION Silicification in angiosperms is a phenomenon that has attracted increasing attention in recent years. It is now widely acknowledged that silicification has many benefits to angiosperms (Richmond and Sussman, 2003; Ma and Yamaji, 2008; Epstein, 2009; Guntzer et al., 2012), and that it probably plays appreciable roles at the ecosystem and landscape levels as well (Cooke and Leishman...
Biosilicification sets the standard for the localized in vitro precipitation of silica at low orthosilicate concentrations in aqueous environment under ambient conditions. Numerous parameters must be controlled for the development of new technologies in designing inventive nanosilica structures, which are able to challenge the biological templates. A long neglected requirement that came into fo...
Bioinspired by diatoms, biomimetic silicification confers an artificial shell on cyanobacteria to alleviate photoinhibition; thus, the photosynthesis of the resulting cyanobacteria@SiO2 becomes more efficient under high light conditions.
The interaction between iron availability and the phytoplankton elemental composition was investigated during the in situ iron fertilization experiment EIFEX and in laboratory experiments with the Southern Ocean diatom species Fragilariopsis kerguelensis and Chaetoceros dichaeta. Contrary to other in situ iron fertilization experiments we observed an increase in the BSi:POC, BSi:PON, and BSi:PO...
The diagenetic changes of the Lower-Middle Eocene limestones in the area to the west of AssiutMinia Stretch include the following processes: compaction, cementation, neomorphism, silicification, glauconitization and ferrugination. The compaction is represented by mechanical and chemical types. Cementation is either shallow submarine (represented by micrite, fibrous calcite and isopachous calcit...
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