Plant-Soil Interaction at Super-strong Acid Range

研究了超强酸条件下植物-土壤相互作用，得到以下结果.阐明了盐土酸性特征与植被的关系。通过对日本和韩国茶园土壤的实地调查，明确了茶园土壤的酸性特征和茶树根系的生长分布。日本茶园土壤pH<4.0，土壤中粘土矿物遭到破坏，导致排水沟中低结晶铝硅酸盐的形成.利用~ 1H Al NMR研究了Al十三聚体在土壤溶液中的行为<27>，阐明了Al十三聚体是不稳定的，Al -腐殖酸复合体是可溶性Al的重要来源.结果表明，热带泥炭土和茶园土壤有机质矿化受降雨量、地下水变化、土壤pH和土壤Eh的影响。阐明了铝胁迫下木麻黄的促生机制和铝积累机制，并阐明了铝与有机酸的螯合作用是植物耐铝的重要机制.小麦、大麦和黑麦的耐铝机制是通过分泌有机酸来实现的，水稻耐铝基因存在于第6号染色体上，是一个基因调控.构建了具有有机酸释放能力的转基因耐铝拟南芥和大麦.阐明了植物耐低磷性与有机酸释放能力的关系.通过长期定位试验，阐明了重施化肥对土壤强酸化的作用机理，认为土壤交换性铝是重要的植物毒害铝。

Plant-soil interaction at super-strong acid range was examined and following results were obtained.1. Relationship between the acid characteristics and vegetation of the solfatara soil was clarified. Field investigation of the tea garden soil was done both in Japan and South Korea, Acid characteristics of the soil and the growth and distribution of tea root were clarified. Moreover, it was clarified that the tea garden soil in Japan showed soil pH<4.0, and the destruction of the clay mineral occurred in the soil resulting genesis of low crystalline alumino-silicate in the drainage canal.2. Behavior of Al tridecamer in the soil solution was examined using ^<27>Al NMR and it was clarified that Al tridecamer was not stable, and Al - humus complex was an important source for soluble Al.3. It was clarified that mineralization of soil organic matters both in the tropical peat soil and tea garden soil were ruled by the amount of the rainfall, underground water change, soil pH and soil Eh.4. Growth promotion mechanism and Al accumulation mechanism of Melastoma were clarified, and it was also clarified that Al chelation with the organic acid released was important as the Al tolerance mechanism of plants.5. Al tolerance mechanism of backwheat, barley and rye was attributed to the secretion of organic acids, and Al tolerant gene of the rice existed in the No6 chromosome and was one gene regulation.6. Genetically modified Al tolerant Arabidopsis and barley with the ability of the organic acid release were created.7. Relationship between a low phosphoric acid resistant and the ability of organic acid release in plant was clarified.8. Mechanism of the strong acidification by heavy application of fertilizers in Andisol was clarified in long term field experiment, and soil exchangeable Al was important as phytotoxic Al.