Effects of Various Anions on Absorption and Toxicity of Lead in Plants

식물체의 연(Pb) 흡수 및 유해성에 미치는 음이온의 영향

The seeds of bean(Glycine max M.) and corn(Zea mays L.) soaked in 5000ppm lead solution for 24 hours were sowed in the flowerpots being placed sandy-clay soil under the field condition. The fixed concentrations of various anions and 2000 ppm lead were supplied alternately in the sandy-clay soi of the flowerpots at two days interval from May to July in 1976. After the plants were harvested prior to the flowering stage, the lead contents of plnat and soil were analyzed by atomic absorption spectrophotometer. The lead contents absorbed by the plant roots showed the highest in an weak acid soil of the best suitable condition of plant growth. The absorption of lead by the plant roots was inhibited by the various anions, especially divalent anions of the soil. Some phosphate anions inhibited lead absorption more than otehr various anions in the soil. The more various anions were in the soil, the more plants could be protected from the lead toxicity. In the case of lead supply in the soil, 99.5% of lead was accumulated in the upper layer of the soil(0-10cm), and 0.5% of lead accumulated in the lower layer (10-20cm). Therefore, the yellow-brown and white symptoms on the leaves and the inhibition of root growth by lead toxicity was increased in the early stage of the germination, however decreased in accordance with the progress of the growing stage becuase of the root growth toward beneath the lower layer of the soil. In spite of the contents of 3773ppm lead in the soil, the symptoms of lead toxicity was not found in the grown plants. At that time the lead contents of the plants absorbed from the soil were minimum 0.78ppm and maximum 3.64ppm through the growing stage.