A scanning proton microprobe study of macrohairs from the lemma of the grass Phalaris canariensis L

Abstract

Proton-induced X-ray emission combined with a scanning proton microprobe has been used to investigate the distribution of inorganic elements in silicifying macrohairs from the lemma of the grass Phalaris canariensis L. Results, presented in the form of X-ray spectra and two-dimensional elemental maps, showed that the inorganic elements Si, K, P, S and Cl were spatially organized within the macrohairs during the different stages of silicification. Much lower quantities of all elements except silicon were found in the mature macrohairs. It is suggested that these changes in the inorganic content of the macrohairs are related to a silicification process that is associated with cellular activity.

Isolation of a wide range of minerals from a thermally treated plant: Equisetum arvense, a Mare’s tale

“…Back in the 1980s, Williams and co-workers were one of the first groups to characterize the nature of silica in biological systems by using transmission electron microscopy, FTIR and NMR spectroscopy [5]. This natural silica, often referred to as biogenic silica, is present in the form of amorphous silica [5, 6] and for some plants seems to be an essential mineral for growth [7]. The ability of plants to produce biogenic silica with a wide range of morphologies under mild physiological conditions is of great interest to scientists (and industry); as it gives the material exceptional properties, such as ordered hierarchical porous structures applicable for catalysis [8], biosensing [9] and biomedical applications [9].…”

“…cellulose), proteins, other carbohydrates, lipids, metal ions (such as Ca, K, S, Cl, Na, Al and P), and phenolic compounds, which also play an important role in the hierarchical structures of biosilica [10]. The distribution and amount of silicon and other metal ions vary between individual plant families [11] and, within the plant, depending on the anatomical region studied [6]. For example, macrohairs from the lemma of the grass Phalaris canariensis L., showed a higher deposition of silicon, as silica throughout the macrohair for the mature stages of the plant; whereas for early stages (immature plant), silicon, as silica was mainly deposited at the tip of the microhair [6].…”

“…The distribution and amount of silicon and other metal ions vary between individual plant families [11] and, within the plant, depending on the anatomical region studied [6]. For example, macrohairs from the lemma of the grass Phalaris canariensis L., showed a higher deposition of silicon, as silica throughout the macrohair for the mature stages of the plant; whereas for early stages (immature plant), silicon, as silica was mainly deposited at the tip of the microhair [6]. In addition, the silica formed in these plant hairs was remarkably free of metal ions [6].…”

Irrigation and phytolith formation: an experimental study

“…When nitrogen is added to soil, the percentage of silicon in wheat decreases (Hutton and Norrish, 1974), while sodium fluoride inhibits silicon uptake in rice (Mitsui and Takatoh, 1959;Okuda and Takahashi, 1965). Other variables that affect silicon uptake are species (Parry and Smithson, 1958, 1966; for a review of silicon uptake in different species see Lewin and Reimann, 1969, p. 294) and plant age (Sangster, 1970;Bartoli and Souchier, 1978;Perry et al, 1984).…”

Microfósseis contidos no cálculo dentário como evidência do uso de recursos vegetais nos sambaquis de Jabuticabeira II (SC) e Moraes (SP)

“…Isso estabeleceu a base comparativa moderna para identificação de plantas fósseis. Os últimos anos desse período apresentaram um decréscimo no estudo de fitólitos no solo e em sedimentos, mas ainda continuaram sendo realizadas pesquisas relacionadas ao estudo de estágios de desenvolvimento da silicificação, características ultraestruturais das células silicificadas e suas funções morfológicas (Hodson et al, 1984;Perry et al, 1984;Sangster, 1985appud Piperno, 1988 (Piperno, 1988).…”