Development of Efficient Recycling Utilization Method of Phosphorus Resources by Using Acid Phosphatase-Secreting Function of Plant Roots

(1)对16种农田和荒地植物根际和土壤中酸性磷酸酶活性进行了研究。根际活性是散装土壤的1.1 ~ 26.8倍。(2)在土壤培养实验中，认为露平、番茄和azuki根部分泌的酸性磷酸酶水解了有机磷酸盐化合物，释放出无机磷酸盐，从而增加了这些植物对磷的吸收。(3)露平根分泌的酸性磷酸酶能水解玉米叶片和城市污泥中含有的有机磷酸盐化合物，释放无机磷酸盐。(4)在土壤培养条件下，甜菜和番茄对低磷土壤耐受能力较弱，在根际添加芦萍粗分泌酸性磷酸酶溶液，可提高甜菜和番茄对磷的吸收，促进其生长。(5)阐明了紫穗槐根系各部位分泌的酸性磷酸酶较多。该酶主要在表皮细胞中合成，并有效地分泌到根际。轻度缺磷时，其合成和分泌增强。(6)卢平与番茄根系分泌的酸性磷酸酶特征差异不大，但其分泌量远高于番茄。(7)露平根分泌的酸性磷酸酶分布在距根表面2.5 mm范围内。根际有机磷化合物的耗竭与酸性磷酸酶在根际的分布规律相吻合。(8)柠檬酸、苹果酸、草酸等有机酸的分布规律与酸性磷酸酶的分布规律相似。这些有机酸从土壤中难溶的无机磷酸盐化合物中释放出磷酸盐。(9)从这些实验结果可以看出，植物根系分泌酸性磷酸酶的功能可以用于开发磷资源的高效循环利用，而世界上磷资源的储存量有限。少

(1) Acid phosphatase activities in the rhizosphere and bulk soils of sixteen plants grown in the agricultural fields and wild lands were investigated. The activity in the rhizosphere was 1.1-26.8 times higher than that in bulk soils. (2) In the soil culture experiments, it was assumed that acid phosphatase secreted from roots of lupin, tomato and azuki been, hydrolized organic phosphate compounds and released inorganic phosphate, thus increased absorption of phophorus by these plants. (3) Acid phosphatase secreted from lupin roots hydrolyzed organic phosphate compounds containing in the maize leaves and city sludges and released inorganic phosphate. (4) Phosphorus absorption of sugar beet and tomato, which are low in low phosphorus soil tolerance, grown in the soil culture condition was increased and the growth was improved by adding crude secreted acid phosphatase solution, obtained from lupin, to the rhizosphere of these plants. (5) It was clarified that acid phosphatase was secreted … More from all parts of root system in lupin. The enzyme was assumed to be synthesized mainly in the epidermis cells and secreted to the rhizosphere efficiently. the synthesis and secretion were enhanced when the plants sufferred from phosphorus deficiency lightly. (6) Characteristics of acid phosphatase secreted from roots of lupin and tomato were not quite different, but amount of the enzyme secreted was far lager in lupin than in tomato. (7) The acid phosphatase secreted from lupin roots was distributed within 2.5 mm from the root surface. Depletion of organic phosphate compounds in the rhizosphere was well corresponded to the distribution pattern of acid phosphatase in the rhizosphere. (8) It was shown that the distribution pattern of organic acids such as citric acid, malic acid and oxalic acid was similar to that of acid phosphatase. These organic acids released phosphate from difficultly soluble inorganic phosphate compounds contained in soils. (9) From these experimental results, it was concluded that acid phosphatase-secreting function of plant roots is able to be used for the development of efficient recycling utilization of phosphorus resources, of which deposited amount in the world is limited. Less