| Budget Amount *help |
¥5,800,000 (Direct Cost: ¥5,800,000)
Fiscal Year 1994: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1993: ¥4,000,000 (Direct Cost: ¥4,000,000)
|
|---|
| Research Abstract |
(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
|
