Lemna (duckweed) as an indicator of acid water.

莱姆纳是一种对重金属和其他水污染物非常敏感的植物。此外，由于它的体积小，繁殖速度快，对实验很有用。我们曾多次尝试将莱姆纳作为水体污染检测的指示种。本课题主要对柠檬草作为酸性水指示剂的利用进行了研究。不同ph条件下Lemna的生长和增殖研究表明，在ph为4 - 6的培养基上，Lemna的生长和增殖最有效。在pH3.6的培养基上，Lemna不能生长，24h内死亡。不同pH下Lemna对重金属的吸收受介质pH的影响，高pH的介质影响Lemna对重金属更敏感。结果表明，重金属的大量吸收和积累导致了lemna对重金属的高敏感性。羊草在河水和雨水中的生长情况在雨水中生长时，羊草的生长速度非常慢。pH值越高，生长速度越快。培养基的pH值对在河水和污水上的生长也有影响。

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.