Silicon Uptake (silicon + uptake)

Distribution by Scientific Domains


Selected Abstracts


Silicon-mediated resistance of sugarcane to Eldana saccharina Walker (Lepidoptera: Pyralidae): effects of silicon source and cultivar

JOURNAL OF APPLIED ENTOMOLOGY, Issue 8 2006
M. G. Keeping
Abstract:, The effects of four silicon sources , a USA calcium silicate, a local (South African) calcium silicate, Slagment® and fly ash , on the resistance of sugarcane cultivars (two resistant and two susceptible) to Eldana saccharina Walker (Lepidoptera: Pyralidae) were studied in a potted sugarcane trial. Silicon sources were applied at 5000 or 10 000 kg/ha for the calcium silicates and Slagment; fly ash was applied at 15 000 or 30 000 kg/ha. The greatest increase in plant silicon content (particularly in stalks) was recorded for plants treated with local calcium silicate. Silicon uptake did not vary significantly between the susceptible and resistant cultivars, although the resistant cultivars had inherently higher silicon content than the susceptible ones. Treatment with silicon significantly reduced borer damage and borer performance at the higher treatment level. In general, borer damage and performance decreased with increasing rates of applied silicon and both variables were inversely related with per cent stalk silicon. On average, the higher silicon rate reduced damage by 34% in the susceptible cultivars and by 26% in the resistant cultivars, supporting the argument that susceptible cultivars benefit more from silicon treatments than resistant ones. We propose that calcium silicate amendments could be employed in the integrated, area-wide management of E. saccharina and in the management of soil acidity, both of which are widespread problems in the South African sugar industry. [source]


Effects of active silicon uptake by rice on 29Si fractionation in various plant parts,

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 16 2009
Jan Reent Köster
Rice (Oryza sativa L.) accumulates large amounts of silicon which improves its growth and health due to enhanced resistance to biotic and abiotic stresses. Silicon uptake and loading to xylem in rice are predominantly active processes performed by transporters encoded by the recently identified genes Lsi1 (Si influx transporter gene) and Lsi2 (Si efflux transporter gene). Silicon deposition in rice during translocation to upper plant tissues is known to discriminate against the heavier isotopes 29Si and 30Si, resulting in isotope fractionation within the plant. We analyzed straw and husk samples of rice mutants defective in Lsi1, Lsi2 or both for silicon content and ,29Si using isotope ratio mass spectrometry (IRMS) and compared these results with those for the corresponding wild-type varieties (WT). The silicon content was higher in husk than in straw. All the mutant rice lines showed clearly lower silicon content than the WT lines (4,23% Si of WT). The ,29Si was lower in straw and husk for the uptake defective mutant (lsi1) than for WT, albeit ,29Si was 0.3, higher in husk than in straw in both lines. The effect of defective efflux (lsi2) differed for straw and husk with higher ,29Si in straw, but lower ,29Si in husk while WT showed similar ,29Si in both fractions. These initial results show the potential of Si isotopes to enlighten the influence of active uptake on translocation and deposition processes in the plant. Copyright © 2009 John Wiley & Sons, Ltd. [source]


When to say when: can excessive drinking explain silicon uptake in diatoms?

BIOESSAYS, Issue 3 2009
Kimberlee Thamatrakoln
Abstract Diatoms are the single most important drivers of the oceanic silicon biogeochemical cycle. Due to their considerable promise in nanotechnology, there is tremendous interest in understanding the mechanism by which they produce their intricately and ornately decorated silica-based cell wall. Although specific proteins have been implicated in some of the key steps of silicification, the exact mechanisms are poorly understood. Silicon transporters, identified in both diatoms and silicoflagellates, are hypothesized to mediate silicon uptake. Recently, macropinocytosis, the non-specific engulfment of extracellular fluid, was proposed as a more energetically favorable uptake mechanism, which can also explain the long-observed effect of salinity on frustule morphology. We explore the bioenergetic, membrane recycling, and vacuolar volume requirements that must be satisfied for pinocytosis-mediated silicon uptake. These calculated requirements contrast starkly with existing data on diatom physiology, uptake kinetics, growth, and ultrastructure, leading us to conclude that pinocytosis cannot be the primary mechanism of silicon uptake. [source]