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Plant growth conditions alter phytolith carbon.

Gallagher KL, Alfonso-Garcia A, Sanchez J, Potma EO, Santos GM - Front Plant Sci (2015)

Bottom Line: Previous work has suggested that plant silica is associated with compounds such as proteins, lipids, lignin, and carbohydrate complexes.These Raman spectra exhibited variability of spectral signatures and of relative intensities between sample treatments indicating that differing growth conditions altered the phytolith carbon.This may have strong implications for understanding the mechanism of phytolith formation, and for use of phytolith carbon isotope values in dating or paleoclimate reconstruction.

View Article: PubMed Central - PubMed

Affiliation: Department of Earth Systems Sciences, University of California, Irvine Irvine, CA, USA.

ABSTRACT
Many plants, including grasses and some important human food sources, accumulate, and precipitate silica in their cells to form opaline phytoliths. These phytoliths contain small amounts of organic matter (OM) that are trapped during the process of silicification. Previous work has suggested that plant silica is associated with compounds such as proteins, lipids, lignin, and carbohydrate complexes. It is not known whether these compounds are cellular components passively encapsulated as the cell silicifies, polymers actively involved in the precipitation process or random compounds assimilated by the plant and discarded into a "glass wastebasket." Here, we used Raman spectroscopy to map the distribution of OM in phytoliths, and to analyze individual phytoliths isolated from Sorghum bicolor plants grown under different laboratory treatments. Using mapping, we showed that OM in phytoliths is distributed throughout the silica and is not related to dark spots visible in light microscopy, previously assumed to be the repository for phytolith OM. The Raman spectra exhibited common bands indicative of C-H stretching modes of general OM, and further more diagnostic bands consistent with carbohydrates, lignins, and other OM. These Raman spectra exhibited variability of spectral signatures and of relative intensities between sample treatments indicating that differing growth conditions altered the phytolith carbon. This may have strong implications for understanding the mechanism of phytolith formation, and for use of phytolith carbon isotope values in dating or paleoclimate reconstruction.

No MeSH data available.


Related in: MedlinePlus

Scanning electron micrographs showed that phytoliths obtained from the extraction exhibited a variety of shapes consistent with silica deposition both within and between cells (A, 200 μm scale bar). For consistency, only the bilobate morphology, consistent with silica precipitated within cells (B, 10 μm scale bar) was used for this study. Phytoliths from sample treatment E are shown here.
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Figure 1: Scanning electron micrographs showed that phytoliths obtained from the extraction exhibited a variety of shapes consistent with silica deposition both within and between cells (A, 200 μm scale bar). For consistency, only the bilobate morphology, consistent with silica precipitated within cells (B, 10 μm scale bar) was used for this study. Phytoliths from sample treatment E are shown here.

Mentions: The phytolith samples exhibited a variety of morphologies based upon the cells or tissues in which the silica precipitated (Figure 1). Atypical silica bodies (not originating from specific silica cells) are well-known (Blackman, 1969), and were most notable in samples with higher silica inputs (Treatments C, D, E, and F) where intercalated silica sheets, casts of stomata, and broken pieces were observed. For consistency in our study, only bilobate phytoliths (30 phytoliths per treatment x 6 treatments; Figure 1B), typical of Sorghum bicolor silica cells, were randomly chosen in each sample for Raman analysis. For the MSG70 soil phytoliths only the trapezoidal shape, typical of a grass short cell was evaluated (n = 30 phytoliths).


Plant growth conditions alter phytolith carbon.

Gallagher KL, Alfonso-Garcia A, Sanchez J, Potma EO, Santos GM - Front Plant Sci (2015)

Scanning electron micrographs showed that phytoliths obtained from the extraction exhibited a variety of shapes consistent with silica deposition both within and between cells (A, 200 μm scale bar). For consistency, only the bilobate morphology, consistent with silica precipitated within cells (B, 10 μm scale bar) was used for this study. Phytoliths from sample treatment E are shown here.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4585121&req=5

Figure 1: Scanning electron micrographs showed that phytoliths obtained from the extraction exhibited a variety of shapes consistent with silica deposition both within and between cells (A, 200 μm scale bar). For consistency, only the bilobate morphology, consistent with silica precipitated within cells (B, 10 μm scale bar) was used for this study. Phytoliths from sample treatment E are shown here.
Mentions: The phytolith samples exhibited a variety of morphologies based upon the cells or tissues in which the silica precipitated (Figure 1). Atypical silica bodies (not originating from specific silica cells) are well-known (Blackman, 1969), and were most notable in samples with higher silica inputs (Treatments C, D, E, and F) where intercalated silica sheets, casts of stomata, and broken pieces were observed. For consistency in our study, only bilobate phytoliths (30 phytoliths per treatment x 6 treatments; Figure 1B), typical of Sorghum bicolor silica cells, were randomly chosen in each sample for Raman analysis. For the MSG70 soil phytoliths only the trapezoidal shape, typical of a grass short cell was evaluated (n = 30 phytoliths).

Bottom Line: Previous work has suggested that plant silica is associated with compounds such as proteins, lipids, lignin, and carbohydrate complexes.These Raman spectra exhibited variability of spectral signatures and of relative intensities between sample treatments indicating that differing growth conditions altered the phytolith carbon.This may have strong implications for understanding the mechanism of phytolith formation, and for use of phytolith carbon isotope values in dating or paleoclimate reconstruction.

View Article: PubMed Central - PubMed

Affiliation: Department of Earth Systems Sciences, University of California, Irvine Irvine, CA, USA.

ABSTRACT
Many plants, including grasses and some important human food sources, accumulate, and precipitate silica in their cells to form opaline phytoliths. These phytoliths contain small amounts of organic matter (OM) that are trapped during the process of silicification. Previous work has suggested that plant silica is associated with compounds such as proteins, lipids, lignin, and carbohydrate complexes. It is not known whether these compounds are cellular components passively encapsulated as the cell silicifies, polymers actively involved in the precipitation process or random compounds assimilated by the plant and discarded into a "glass wastebasket." Here, we used Raman spectroscopy to map the distribution of OM in phytoliths, and to analyze individual phytoliths isolated from Sorghum bicolor plants grown under different laboratory treatments. Using mapping, we showed that OM in phytoliths is distributed throughout the silica and is not related to dark spots visible in light microscopy, previously assumed to be the repository for phytolith OM. The Raman spectra exhibited common bands indicative of C-H stretching modes of general OM, and further more diagnostic bands consistent with carbohydrates, lignins, and other OM. These Raman spectra exhibited variability of spectral signatures and of relative intensities between sample treatments indicating that differing growth conditions altered the phytolith carbon. This may have strong implications for understanding the mechanism of phytolith formation, and for use of phytolith carbon isotope values in dating or paleoclimate reconstruction.

No MeSH data available.


Related in: MedlinePlus