| Research Abstract |
To elucidate the nutritional characteristics of plants adapted to low pH soils, nutrients content in leaves was compared among plants grown in alluvial soil (Botanical garden of Hokkaido University), acid soil, and serpentine soil. Among macro nutrients in leaves, variation of N,P,and K content was small among soils, Ca content was lower in acid soil and serpentine soil than in alluvial soil, and Mg content was lower in acid soil, or higher in serpentine soil than in alluvial soil. Among micro nutrients in leaves, Fe and Mn content was lower and higher, respectively in acid soil and serpentine soil than in alluvial soil. It is expected that Al content will be high in acid soils, and will be low in high pH soil (serpentine soil), however Al content in leaves did not show the consistent tendency among soils, indicating that Al content reflect on the plant own characteristics, not on soil properties. As a results, N,P,K,Al nutrients in leaves are regulated by plant own nutritional charact
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eristics, on the other hand, Ca, Mg, Fe, and Mn nutrients in leaves are affected by soil nutrients.
In Southern Peninsular Thailand, adverse soils such as ; acid sulfate, peat, sandy podozol, and saline soils are distributed. Melastoma malabathricum and Melaleuca cajuputi were dominant plants grown in low pH and peat soils. M.malabathricum accumulated the huge amount of aluminum (Al) in leaves, especially in new growing leaves, therefore, M.malabathricum is designated as Al accumulator plant. While, M.cajuputi did not accumulate Al in shoot, therefore, M.cajuputi is designated typically as Al excluder plant. Thus, M.Malabathricum and M.cajuputi adapt well to low pH soils, while they have a different strategy for Al. When low pH tolerant plants (especially M.malabathricum and M.cajuputi) were hydroponically cultivated in Al-P equilibrium system with 3 Al levels at pH4.0, these plants grew well by Al application, and could not absorbed phosphorous and nitrogen without Al, indicating that Al is important element for especially phosphorous adsorption in both Al accumulator plants and Al excluder plants. Less
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