Metroxylon Sagu Rottb Research Articles

Starch Properties of the Sago Palm (Metroxylon sagu Rottb.) in Different Soils

We investigated the relationships between starch concentrations and activities of starch synthetic enzymes in sago palms (Metroxylon sagu Rottb.) under acid sulfate and mineral soil conditions. Plants grown naturally that had reached their maturated stage were sampled. We found that the growth in acid sulfate soil is lower than that in mineral soil and that starch granules were larger and there was more amylase activity in acid sulfate soil than in mineral soil. Lower amylase activity in mineral soil could eliminate the degradation of starch, making the smaller granules suitable for storing large amounts of starch in a limited space inside cells.

Nutrient availability and response of sago palm (Metroxylon sago Rottb.) to controlled release N fertilizer on coastal lowland peat in the tropics

Sago palms (Metroxylon sagu Rottb.) growing on peat soils were found to grow more slowly and to show a lower production than palms growing on mineral soils. This difference was related to the physical and chemical constraints of peat soils, which include low bulk density, high acidity, and low N, P, K, Ca, Zn, and Cu levels. In coastal lowland peat soils, the distance from the sea has been found to be an important determinant of soil elemental composition. We predicted that a sufficient supply of N at the rosette stage would improve sago palm growth and that the availability of N in soil to which controlled release N fertilizer was applied might be higher than that in soil treated with soluble fertilizer. To investigate the changes in the nutrient composition of peat soils at various distances from the sea and the effect on sago palm growth, we studied sago palm areas in Indonesia and Malaysia. To observe the influence of N on the growth performance, we also conducted a fertilizer experiment on coastal lowland peat soil in Indonesia. Distance from the sea had no significant effect on the cation concentration in the soil solution (with the exception of Mg) or on the levels of soil-exchangeable cations. No significant differences were observed between the concentrations of exchangeable cations in surface peat soils and those in mature leaves. However, the concentrations of K, Na, and Ca in mature leaves increased significantly with their concentrations in the soil solution. This finding implies that the concentrations of cations in sago palm leaves depend directly on the concentrations of cations in the soil solution. No significant effect of N fertilizers on plant height and leaf formation was observed. N fertilizers applied twice a year did not affect appreciably the foliar concentration of N determined in December 1998 (5 months after the initial application) and December 1999. In June 2000, we detected a significantly higher concentration of N (p < 0.01) in young leaves of the palms treated with LP-100 or urea than in control leaves. However, no significant difference was detected between the LP-100 and urea treatments in the concentration of N in both mature and young leaves. This finding indicated that the concentration of N in sago palm leaves increased with the level of soil-applied N, regardless of whether N was applied as controlled release fertilizer or in the soluble form. We anticipate that a significant difference in the effects of these N fertilizers may occur during the next rainy season, when there should be a considerable loss of soluble N.

Morphological and Anatomical Observations of Adventitious and Lateral Roots of Sago Palms

Sago palm (Metroxylon sagu Rottb.), which produces starch in large quantities in its trunk, could become one of the most important nutritious food resources in the near future. Although its root functions are thought to be very important for the enormous shoot growth, the morphological and anatomical studies are limited. This study investigates external and internal structures of sago roots with reference to their functions to distinguish two types of roots in each plant; i.e., large (about 6-11 mm diameter) and small (about 4-6 mm diameter) roots. Large roots were adventitious roots whose primordia were formed just inside the epidermis in the stem, emerged from the trunk surface and grew downward into the soil. Small roots were lateral roots whose primordia were formed on large roots running horizontally or on other small roots, grew not only downward and obliquely in both deep peat and mineral soils, but also right above in deep peat soils. Anatomical observations revealed that both large and small roots had the same internal structures containing epidermis, exodermis, suberized sclerenchyma cells, cortex and stele, with only differences in their sizes or cell numbers. Both roots had characteristic development of schizogenous or lysigenous aerenchyma, but seem to have different functions. Root primordia were formed successively throughout the trunk. Root primordia in the lower trunk had a large diameter, while density of root primordia per unit trunk surface area was high in the upper trunk.

Sago Palm (Metroxylon Sagu, Arecaceae) production in the Eastern Archipelago of Indonesia: Variation in morphological characteristics and pith dry-matter yield

Eleven local varieties of sago palm (Metroxylon sagu Rottb.) in southeast and north Sulawesi and in northern Maluku were studied: one variety with a weak black band on the back of the petiole: three varieties with a brown band on the back of the petiole: seven bandless varieties comprising two spineless, four short spine and one long spine types. Large variation in morphological characteristics and pith dry-matter yield were estimated at 13 to 34% and 55%, respectively. The difference in pith dry-matter yield is mainly attributed to trunk diameter and dry-matter percentage of pith. Trunk diameter was not affected by the length of growth period, which might reflect the palm’s own characteristics, such as genetic background and growth environment. The dry-matter percentage of pith was not related to any characteristics measured. The pith dry-matter yield was highest in the short spine type, followed by the spineless and the long spine types.

Nutritional characteristics of sago palm and oil palm in tropical peat soil

To make clear the nutritional characteristics of sago palm (Metroxylon sagu Rottb.) and oil palm (Elaeis guineensin Jacq.) grown in tropical peat soil, minerals concentration, organic compounds concentration, and photo‐synthetic rate were estimated, and the obtained results were as follows. Since, the nitrogen (N), phosphorus (P), calcium (Ca), magnesium (Mg), and sodium (Na) concentration in mature leaves and trunk were higher in the oil palm than in the sago palm, but potassium (K) concentration was higher in the sago palm than in the oil palm, the minerals (especially N, P, Ca, and Mg) requirement for the oil palm were higher than in the sago palm. This indicates that the sago palm will adapt better than the oil palm to soils with poor nutrients. The manganese (Mn) and zinc (Zn) concentration in leaves of the sago palm and Ca and aluminum (Al) concentration in leaves of the oil palm increased with the increase of aging, indicating that those elements are eliminated from plants through leaf senescence. In the sago palm, the N and P distribution ratio to leaves remained almost constant during growth, indicating that N and P were predominantly distributed to leaves for maintaining leaf function. The photosynthetic rate [μmole carbon dioxide (CO2) m2 LA sec‐1] at light saturation was lower in the sago palm (5.8) and oil palm (10.0) than in wheat (25.4). As leaf longevity of sago and oil palms was longer (about 12 times) than that of wheat (Triticum aevstium L.), and the minerals concentration and photosynthetic rate remained constant for a long duration of growth, the cumulative carbon (C) accumulation per unit dry weight (photosynthetic rate x leaf longevity) in the individual leaf is assumed to be equal or greater than that of wheat. The photosynthetic ability of sago and oil palms leaves is very important for understanding why sago and oil palms have high productivity in spite of a low nutrient environment.

THE VARIABILITY OF THE SAGO PALM AND THE NEED AND POSSIBILITIES FOR ITS CONSERVATION

In the wild and in cultivation, sago palm (Metroxylon sagu Rottb.) is mostly propagated vegetatively through its suckers. Generative propagation occurs to a limited extent; there are strong indications of sago palm being largely an obligatory cross-pollinator. This opens the possibility of the existence of an endless amount of clonal varieties of sago palm, which is confirmed by the endless amount of different names for locally distinguished varieties in the areas where sago palm occurs naturally. Sago palm's great variability is now threatened by the decrease in area under natural and semi-natural sago forest in the centres of diversity (New Guinea, the Moluccas) and by the sole attention to high-yielding, quickly-maturing varieties for plantation purposes. A comprehensive plan is required for the conservation of the existing germplasm for future selection and breeding. The problems and uncertainties with in-vitro and standing in-situ germplasm collections are such that gathering varieties from the wild and planting them in special regional germplasm gardens seems the only viable option. Issues of collecting and describing material are dealt with, including the evaluation of information from local informants. Centres of sago palm diversity seem to coincide with centres of language diversity. It is demonstrated, however, that differences in name cannot be attributed singly to differences in language. An extensive list is given of examples of locally distinguished varieties reported in literature, and of varieties encountered during the author's 1988–1990 research on sago in the Moluccas and during a two-month all-Indonesia study tour in 1992.

Use of low-cost gelling agents and support matrices for industrial scale plant tissue culture

The efficacies of sago (from Metroxylon sagu Rottb.) and isubgol (from Plantago ovata Forsk.) as gelling agents and those of filter paper, nylon cloth, polystyrene foam and glass wool cloth as support matrices have been tested for the propagation of plantlets of chrysanthemum (Dendranthema grandiflora Tzvelev). The performances of these low-cost gelling agents and matrices were found satisfactory and could compare well with that of agar. Glass wool cloth was, however, found to be the best matrix. Comparative cost estimations of the matrices and gelling agents have been presented and their merits and/or demerits have been discussed. For a given quantity of a medium, sago and isubgol cost about 1/18th and 1/10th respectively, compared to agar (e.g. Sigma, purified agar, No. A. 7921). The corresponding costs of the matrices are also less than that of agar. The results showed the potential of the substitutes for economic commercial application, replacing the costliest, though not indispensable, gelling agent agar.