Phytoliths of Indian grasses and their potential use in identification

Abstract

Phytoliths are amorphous silicon dioxide (SiO2.nH2O) inclusions abundant in leaves, in‐ternodes and glumes in members of Poaceae. They may occur as inclusions filling the entire lumen of the silica cells, bulliform cells and trichomes or may be part of the outer epidermal cell walls. Since phytoliths are resistant to fungal or animal digestive juices, a large quantity of phytoliths accumulate in the soil where grasses grow. Compared with the pollen grains of grasses which tend to be uniform, phytoliths vary in sue and morphology and can be of value in identification at different taxonomic levels and in the dating of past vegetation. The size and shape of phytoliths of about 100 species of grasses from Tamil Nadu, India, have been determined. Silica bodies were observed either after isolation or in cleared leaf blades. Size and shape of phytoliths were determined under a microscope or from micrographs of the specimens. Size and shape can be used to assign the phytoliths to their respective subfamilies and to distinguish some of the grasses at the generic level. Drawings of silica cells and an identification key are provided for 80 species.

Phytolith‐rich biochar: A potential Si fertilizer in desilicated soils

“…Our estimated annual PhSi amount is close to the global estimate (204.8 Tg BSi/year) of annual global crop straw provided by Carey and Fulweiler (2016). The total PhSi amount in crop residues depends on DM biomass, and on plant species or plant part ( Since phytoliths are resistant to fungal or animal digestive juices after grass or crop feed ingestion, significant amounts of PhSi accumulate in animal manures Jones & Handreck, 1967;Krishnan, Samson, Ravichandran, Narasimhan, & Dayanandan, 2000). We estimate that the global PhSi amount in selected manures (cattle, pig, and poultry) amounts to 42.0 Tg Si/ year among which 94.5% is provided by cattle manures (Figure 3a).…”

Quantifiable differences between phytolith assemblages detected at species level: analysis of the leaves of nine Poa species (Poaceae)

“…For example Mejia-Saules and Bisby [10] found distinguishing silica bodies in the lemmae of Melica species. Form and position of phytoliths, which are not greatly influenced by environmental factors but are genetically controlled, may have considerable systematic potential [11][12][13].…”

Taxonomic assessment of opal phytoliths from grasses of deltaic West Bengal, India

“…Various workers from different parts of the globe, proposed different grass phytolith classification schemes and used diverse terms depending on varied criteria (Metcalfe 1960, Twiss et al 1969, Sase and Kondo 1974, Pearsall and Trimble 1983, Brown 1984, Kondo and Sase 1986, Piperno 1988, Mulholland 1989, Pearsall and Piperno 1990, Mulholland and Rapp 1992, Wang and Lu 1993, Fredlund and Tieszen 1994, Kondo et al 1994, Piperno and Pearsall 1998, Runge 1999, Krishnan et al 2000, Pearsall 2000, Lu and Liu 2003a, b, Gallego and Distel 2004, Blinnikov 2005, Madella et al 2005, Honaine et al 2006, Fahmy 2008, Barboni and Bremond 2009, Mercader et al 2010, Ghosh et al 2011, Gu et al 2013, Biswas et al 2016, Neumann et al 2017. Till date, there is no uniform, world-wide accepted grass phytolith classification scheme because of variations in materials, locality, classification parameter etc.…”

“…Phytolith formation in qualitative and quantitative terms is primarily genetically controlled (Dorweiler and Doebley 1997, Piperno et al 2002, Hodson et al 2005, Mitani and Ma 2005, Piperno 2006, Ma et al 2006, 2007a, b, Yamaji et al 2008, Chiba et al 2009, Peleg 2010, Markovich et al 2015, Exley 2015, Kumar et al 2016, McLarnon et al 2017 though environmental factors may sometimes be influential (Jie et al 2010, Liu et al 2013, Dey et al 2015. Due to the strong relationship between plant taxa and phytolith morphometry, these biogenic silicomorphs have been used as a taxonomic proxy (Metcalfe 1960, Twiss 1992, Mulholland and Rapp 1992, Krishnan et al 2000, Raole and Desai 2009, Ball et al 2009, Ahmad et al 2011, Shakoor et al 2014, Jattisha and Sabu 2012, Kealhofer et al 2015, Gu et al 2016, Neumann et al 2017.…”

“…Phytolith characters are considered as genetically governed important trait which may be only slightly influenced by environmental factors (Hodson et al 2005, Mitani and Ma 2005, Piperno 2006). Hence, their considerable diversity, distinctiveness and frequency attributes may provide crucial inputs in grass taxonomy and have been utilized for discriminating grass taxa at various taxonomic levels (Metcalfe 1960, Twiss 1992, Mulholland and Rapp 1992, Krishnan et al 2000, Raole and Desai 2009, Ball et al 2009, Ahmad et al 2011, Jattisha and Sabu 2012, Shakoor et al 2014, Kealhofer et al 2015, Gu et al 2016, Neumann et al 2017.…”