Investigations into Phytoliths as Diagnostic Markers for the Grasses (Poaceae) of Punjab

Abstract

Grasses are known to accumulate amorphous silica (SiO 2 .nH 2 O) within and between cells as silica bodies of characteristic shapes. The position and type of the host cells are the characters that seem to control their shape and size. The present study was carried out to assess and utilize the diagnostic potential of phytolith types in the identification of grass taxa at sub-familial, tribal, generic and specific levels. Clearing solution method was employed for locating the position of phytoliths within and between cells. Dry and wet ashing methods were subsequently employed for their isolation. Scanning Electron Microscopy was performed to study the ultra-structural features of phytoliths. Micromorphometric measurements of phytoliths were carried out with the help of image analysis software (Image J 1.46r). The study has brought out diagnostic potential of phytolith types for characterization of grasses of Punjab plains. For example, hat shaped phytoliths were identified as the diagnostic marker type for Digitaria ciliaris (Retz.) Koeler. However, full taxonomic potential of phytolith types for characterization of taxa can be realized only after further analysis of their physical properties and chemical architecture.

Phytolith profile of Acrachne racemosa (B. Heyne ex Roem. & Schult.) Ohwi (Cynodonteae, Chloridoideae, Poaceae)

“…Phytoliths have been reported mainly from aboveground parts like culm, leaf, and synflorescences [17,22,85,88,[94][95][96][97][98][99][100][101][102][103][104]. But in the present paper, we have increased the scope of phytolith analysis in Poaceae by the study of phytoliths from the underground parts (root) as well [105].…”

“…Phytoliths are inorganic, resistant to decay, and are durable fossils of terrestrial plants. They are released into the soil after the decomposition of plants [10,[15][16][17]. They occur in all types of plants and their parts.…”

“…Types of phytoliths help in the characterization of tribes and genera within Chloridoideae [17]. Based on globular echinate types of phytolith a classification system was proposed which allowed the identification of tribes and subtribes of Amazonian palms [43].…”

Separation of wavy and polylobate forms of phytoliths of the “crenate” morphotype in Pooideae Benth. species of the south of Western Siberia on the basis of phylogenetic data

“…Тем не менее, у большинства видов этой трибы имеются волнистые пластинки, а у Agropyron pectinatum и Elytrigia repens их количество значительно. Полученные данные согласуются с исследованием культурных видов трибы (Shakoor et al, 2014). Для культурных злаков выявлены морфометрические отличия фитолитов соцветий этой трибы от подтрибы Aveninae (трибы Poeae) (Ball et al, 2017).…”

“…Наиболее продвинулись исследования в области применения фитолитов для разграничения видов внутри рода или близких родов (Ball et al, 1996;Krishnan, Samson, 2000;Yost, Blinnikov, 2011;Jattisha, Sabu, 2012, 2015. Встречаются исследования, в которых указана диагностическая значимость на уровне триб (Lu, Liu, 2003a;Shakoor et al, 2014). Сопоставления фитолитного состава с филогенией злаков указывает на наличие форм, характерных на разных таксономических уровнях (Bobrov et al, 2001;Rudall et al, 2014;Hoskova et al, 2021).…”