不同水层光照强度对4种沉水植物生长的影响

Effects of light intensity at different depth of water on growth of 4 submerged plants

选取金鱼藻(Ceratophyllum demersum)、轮叶黑藻(Hydrilla verticillata)、水盾草(Cabomba caroliniana)、苦草(Val-lisneria gigantean)为试验材料,研究不同水层的光照强度对其存活率、株高、生物量等的影响,旨在找出这4种沉水植物在自然条件下的最适生长、最深耐受水层。结果表明:(1)不同沉水植物的最适生长和最深耐受水层不同。本研究条件下金鱼藻在表层(0m)水层生长情况最好,在1.5m水层处基本死亡;水盾草最适宜底层(2.0m)水层环境,在表层水层则存活率最低;苦草生长范围较广,在底层水层亦可生长;轮叶黑藻在表层至0.5m水层处的相对生长率最高,最深耐受水层为1.5m水层。(2)沉水植物恢复重建时,可根据目标水体的水深和水质,以及植物对水层的适应性进行种类选择。

The relative growth rate,plant height and branch number of 4 submerged plants（Ceratophyllum demersum,Vallisneria gigantean,Hydrilla verticillata and Cabomba caroliniana） at different depth of water were studied to determine the effect of light intensity in different water depth on growth of 4 submerged plant.The experiment attempts to explore the optimum and the maximal tolerant depth in water for the four submerged plants.The results showed that water depth had great influence on the growth of plants.Ceratophyllum demersum grew best in the surface layer but they almost entirely died at the depth of 1.5 m.The optimal depth for Cabomba caroliniana growth was the bottom layer,while its relative growth rate was the lowest in the surface layer of water.Vallisneria gigantean could grow in wide range of water depth.The optimal range of water depth for Hydrilla verticillata growth was 0-0.5 m,and the maximal tolerant depth for Hydrilla verticillata was 1.5 m.So,the depth and quality of target water body combined with the adaptability of plant to water depth should be considered when applying submerged plant for water remediation.