Sago palm (Metroxylon rumphii MARTIUS) has been regarded as a typical C3 plant because of a low apparent photosynthetic rate, low light saturation, high CO₂ compensation point, and warm optimum temperature. However, there has been no report on the carbon stable isotope ratio (δ¹³C) of sago palm (Metroxylon sagu Rottb.). In the present study, sago palm leaflets in different growth stages and different leaf positions and sago starch samples were collected in Sungai Talau, Sarawak of Malaysia, Kendari, Sulawesi of Indonesia, and Pangasugan and Hilsig, Leyte of the Philippines, and their δ¹³C values were determined. The δ¹³C of sago samples ranged from -27.6 to -28.8‰, with a mean value of -28.4‰, indicating that sago palm is a C3 plant by means of δ¹³C.

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 Sago palms (Metroxylon sagu Rottb.) are still abundantly present in Leyte and Cebu provinces in the Philippines and are being utilized in the production of flour/starch and thatches. This study tried to elucidate the breaking resistance of sago leaflets to determine the durability of leaflets for making thatches. The mean values of the maximum breaking resistance of the total number of sago leaflets (4 years after transplanting) with and without the main (central) vein (midrib) (n = 10) taken in 2009 were 513 ± 514 gf (gf = 0.00980865 N) and 18.4 ± 7.0 gf, respectively. The mean maximum breaking resistance of sago leaflets 5 years after transplanting showed higher values than those of sago leaflets 4 years after transplanting. The maximum breaking resistance of sago leaflets with and without the vein increased with increasing leaflet weight, suggesting that the main vein of the sago leaflet regulated its breaking resistance. The maximum breaking resistance of sago leaflets followed a polynomial approximation, which indicated the physical development of sago leaflets accompanied by maturation.

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