Phytolith (biogenic opal silica) assemblages in all organs of the palm family are formed by the uptake of silicon from the soil through the root system. Characteristic
Metroxylon sagu phytoliths were counted to evaluate their presence and size distribution in different leaf and leaflet positions at the approaching flowering stage. At the sago field in Pangasugan, Leyte, Philippines, the samples of
M. sagu were collected from upper (the 4th leaf from the apex), middle (the 8th), and lower (the 11th or 14th) leaf portion and from upper, middle and lower leaflet position of each leaf. Phytolith assemblages in
M. sagu leaflets were extracted by a dry combustion method with an electric furnace and described based on morphology and ornamentation according to International Code for Phytolith Nomenclature 1.0 and 2.0 using a light-transmitting and scanning electron microscope. Spheroid echinate phytoliths, which were highly diagnostic with minor exceptions, were observed in the leaflets of
M. sagu (three palms) in Pangasugan. Incinerated leaflet samples amounted to approximately 9% of the oven-dry weight of leaflet. The phytoliths were counted under a light-transmitting microscope. The mean diameter of phytoliths was 13.2 μm. Phytoliths were divided into five classes by diameter size; <5 (A), 5–10 (B), 10–15(C), 15–20 (D), and >20 μm (E) accounted for 11.3, 23.4, 23.5, 25.9,and 15.9% of the total phytoliths, respectively. The number of conical projections (spines) in the five classes ranged from 8 to 34 with a mean value of 24.8. The largest number of spines (more than 30) was found in 15–20 μm (D) and >20μm (E) phytoliths. The increasing trend of the mean number of spines was observed in the increasing diameter of phytoliths with some exceptions. The phytolith assemblages supplied by
M. sagu will contribute to an useful indicator of
M. sagu growth for vegetation reconstruction and archaeological study.
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