The effects of the phosphorylation of native sago starch (NSS) on the physicochemical properties of phosphorylated sago starch (PSS) were investigated. PSS1 was prepared by reacting NSS with sodium tripolyphosphate, and PSS2, with phosphorus oxychloride in aqueous alkaline conditions (pH 8, 9, 10, and 11). The PSS was characterized for its phosphorus, ash, protein, fat, and amylose contents, swelling power and solubility, water-holding capacity, and paste clarity. The phosphorylation condition resulted in a decrease in the fat and protein content and an increase in the ash and amylose content. The phosphorus content of PSS1 prepared at pH 9 was higher than that prepared at other pH values, and that of PSS2 prepared at pH 11 was higher than that prepared at other pH values. The swelling power and water-holding capacity of PSS were higher than those of NSS, while the solubility was lower than that of NSS. The paste clarity of PSS1 was higher than that of NSS, and that of PSS2 was lower.

View full abstract

 Three young sago palms were collected at each sampling site from three locations in South Thailand to investigate the nutrient accumulation in plant tissues of sago palm in the rosette stage with no trunk formation grown at different levels of soil pH. The tendency in the case of Mg²⁺ concentration was displayed a significantly higher concentration in the whole plants of sago palm grown at the neutral pH soil (site 1) than those at the low pH soil (sites 2 and 3), which was similarly to that observed from soil sampled. Contrarily, the N and P concentrations in the whole plants of sago palm grown at the low pH soil (sites 2 and 3) were significantly higher than those at the neutral pH soil (site 1), although there were no differences in the available P and N in the soils at the three sampling sites. In addition, the effect of the difference in soil pH between the neutral pH soil (site 1) and the low pH soil (sites 2 and 3) on the K⁺ and Ca²⁺ concentrations in the whole plants were indistinct. It is likely that sago palm grown at the low pH soil (sites 2 and 3) could maintain the uptake of macronutrients, which may be one of the major reasons that sago palm can adapt to growth in extremely acidic conditions. Furthermore, sago palms at the three sampling sites tended to store a higher Al³⁺ concentration in the cortex of adventitious roots than in other parts, such as the leaflet, and a similar tendency was observed for the accumulation of SO₄^2- and Na⁺ in the plant tissues. It was, therefore, assumed that sago palm grown under any conditions of soil pH might exhibit an avoidance mechanism to restrict the distribution of any excess of undesirable nutrients in plant tissues, which may account for the ability of sago palm to grow in a range of soil pH from 4.3 to 7.0 in natural conditions.

View full abstract

 The study was conducted from May 2008 to May 2009 at Abelisawa village, District of Pohara, Southeast Sulawesi Province, Indonesia, to clarify the effect of seasonal changes in the groundwater level and mineral element concentrations on the early growth of suckers and the mineral element concentrations in leaflets. Two sites under different soil groundwater conditions, dry (D: groundwater approximately 0 to – 15 cm below the soil surface) and waterlogged (W: groundwater approximately 0 to +10 cm above the soil surface), were selected. The groundwater levels were recorded, and the water was sampled to determine the inorganic-N, P, K, Ca, and Mg concentrations, pH, and EC every two months under D and W. Five suckers approximately 1-yearold growing in clumps with their mother palms and other suckers under D and W were selected to measure the growth characters and sample the leaflets of the youngest expanded leaf for the determination of the total-N, P, K, Ca, and Mg concentrations. The groundwater levels during the study period ranged from +2.0 cm to +8.8 cm under W and from +1.1 cm to – 16.3 cm under D. The changes in groundwater levels, however, did not correspond to the amount of rainfall. Few noticeable effects of the groundwater changes on sucker growth, mineral elements concentrations, pH and EC in the groundwater and in the mineral element concentrations of the young expanded leaf were found. These indicate that groundwater levels ranging from +10 cm to – 20 cm will not critically affect sucker growth.

View full abstract