Lemna (duckweed) as an indicator of acid water.

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Lemna is a plant very sensitive to heavy metals and other water pollutants. Furthermore, it is useful for experiments because of its small size and rapid multiplication rate. We have made many attempts to use Lemna as an indicator species for the detection of water pollution. In this project, the study on the utilization of Lemna as an indicator of acid water was made.1. The Growth and the Multiplication of Lemna under various pHIt was made clear that the growth and the multiplication of Lemna were made most effectively on the medium adjusted to pH4 - 6. When Lemna was planted on the medium of pH3.6, it couldn't grow and died within 24hrs.2. The Absorption of Heavy Metals under Various pHThe sensitivity of Lemna to heavy metals was affected by medium pH. The high pH value of the medium affected Lemna more sensitive to heavy metals. And it was shown that more absorption and accumulation of heavy metals resulted in the high sensitivity to heavy metals of Lemna.3. The Growth of Lemna on the River Water and on the Rain WaterWhen grown on the rain water, the growth rate of Lemna was so little. The growth rate was larger on the medium of higher pH value.Growth on the river water and on the sewage water were also affected by medium pH.