水生维管束植物对水体铬污染的反应和净化作用

ON THE RESPONSE OF VASCULAR HYDROPHYTES TO CHROMIUM POLLUTION IN WATER SYSTEM AND ALIGNED EFFECT OF PURIFICATION

在人工培养条件下,沉水和浮水两种水生维管束植物对水体中的Cr(Ⅵ)具有不同的吸收富集能力。在3 ppm的Cr(Ⅵ)溶液中,浮水植物对Cr(Ⅵ)的吸收富集能力高于沉水植物。沉水植物对Cr(Ⅵ)的毒害作用较为敏感,在6 ppm Cr(Ⅵ)的水体中,其伤害症状出现迅速。在1～16ppm的Cr(Ⅵ)浓度范围内,沉水植物苦草的叶绿素含量随Cr(Ⅵ)浓度的增加而下降,叶绿素含量下降百分率与Cr(Ⅵ)浓度二者之间呈现线性关系,因此可用该种植物叶绿素含量的变化来确定Cr(Ⅵ)对植物的伤害阈值。利用对Cr(Ⅵ)反应敏感的苦草这类沉水植物作水体铬污染的生物鉴测是很适宜的。

Two types of vascular hydrophytes, submerged and floating plants were tested with artificial nutrient solution with additional potassium dichromate. All the four species of tested plants absorb and enrich chromium in aqulous solution. The absorbing and enriching abilities are different in different types of quatic plants. The accumulative ability is higher in floating plants than in submerged plants at lower concentration (3ppm) of chromium. Submerged plants are more sensitive to harmful influence of Cr-pollution than floating plants. Within a certair range of concentrations of chromium, there is a linear correlation between the chlorophyll content of vallisneria leves and the concentration of chromium in aqulous solution. Hence the change of chlorophyll content of this plant may be used for an index to determine the threshold concentration of injury of chromium. It is suitable using sensitive plants as vallisneria for biological monitoring to the Cr-pollution in water systems.