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

(1)对田间和野外生长的16种植物根际和土壤中的酸性磷酸酶活性进行了研究。根际活性是土壤活性的1.1-26.8倍。(2)在土壤培养实验中，推测羽扇豆根、番茄和红豆杉根系分泌的酸性磷酸酶能水解有机磷化合物，释放无机磷，从而促进这些植物对磷的吸收。(3)羽扇豆根分泌的酸性磷酸酶能分解玉米叶片和城市污泥中的有机磷化合物，释放出无机磷。(4)对耐低磷土壤条件下生长的甜菜和番茄，在根际添加羽扇豆产酸性磷酸酶粗提液，提高了植株对磷的吸收，促进了植株的生长。(5)证实酸性磷酸酶分泌…。更多来自羽扇豆根系统的所有部分。推测该酶主要在表皮细胞中合成，并有效地分泌到根际。当植物受到轻度缺磷胁迫时，其合成和分泌能力增强。(6)羽扇豆根和番茄根系分泌的酸性磷酸酶特性差异不大，但羽扇豆根分泌量远大于番茄。(7)羽扇豆根分泌的酸性磷酸酶分布在距根表面2.5 mm的范围内。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一致。(8)柠檬酸、苹果酸、草酸等有机酸的分布规律与酸性磷酸酶相似。这些有机酸从土壤中含有的难溶无机磷化合物中释放出磷。(9)实验结果表明，植物根的酸性磷酸酶分泌功能可用于开发磷资源的高效循环利用，目前世界上磷资源的沉降量有限。较少

(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