洱海底泥特性对七种沉水植物生长的影响

为研究洱海底泥特性对沉水植物生长的影响，采用不同比例洱海底泥与湖岸土壤掺混形成五种基质，并分别移栽苦草、黑藻、微齿眼子菜、马来眼子菜、光叶眼子菜、穿叶眼子菜和狐尾藻，进行为期70d的室外生长实验，结果表明不同基质对几种植物的影响具种间差异。（1）在基质为50%深层底泥+50%湖岸土壤（碳、氮、磷含量分别为31.59、0.334和0.095 mg/g）时，苦草、马来眼子菜和光叶眼子菜的株高最大；基质为100%深层底泥（碳、氮、磷含量分别为37.88、0.803和0.149 mg/g）时，黑藻、微齿眼子菜、穿叶眼子菜和狐尾藻的株高最大；（2）基质为100%深层底泥时，苦草、黑藻、微齿眼子菜、马来眼子菜和光叶眼子菜生物量增加最多且相对生长速率最大；基质为100%浅层底泥（碳、氮、磷含量分别为77.37、5.691和0.136 mg/g）时，穿叶眼子菜生物量增加最多，相对生长速率最大；狐尾藻在基质为50%浅层底泥+50%深层底泥（碳、氮、磷含量分别为49.27、2.005和0.131 mg/g）时生物量增加最多，相对生长速率最大；（3）基质为100%湖岸土壤（碳、氮、磷含量分别为22.06、0.327和0.231 mg/g）时，7种沉水植物均生长缓慢，生物量增加较少。综上所述，中营养底泥（碳、氮、磷含量分别为31.59-49.27、0.334-2.005和0.095-0.131 mg/g）更适合沉水植物生长，底泥中过高或过低营养都不利于沉水植物生长。

GROWTH OF SEVEN SUBMERSED MACROPHYTES CULTURED ON FIVE SEDIMENT MIXTURES FROM THE LAKE ERHAI

In an outdoor 70d experiment, seven submersed macrophytes, Vallisneria natans, Hydrilla verticillata, Pota-mogeton maackianus, Potamogeton malaianus, Potamogeton lucens, Potamogeton perfoliatus and Myriophyllum spicatum were cultured on five sediment mixtures consisting of different proportions in lake sediment and local soil from the Lake Erhai, with aims to examine effects of sediment properties on the plant growth. At the end of the experi-ment, V. natans, P. malaianus and P. lucens grown on the sediment mixture of 50% deep-layer lake sediment and 50%local soil (C: 31.59 mg/g; N: 0.334 mg/g; P: 0.095 mg/g), which had the highest shoot heights, and so did for H. verti-cillata, P. maackianus, P. perfoliatus and M. spicatum grown on the 100% deep-layer lake sediment (C: 37.88 mg/g; N:0.803 mg/g; P: 0.149 mg/g). On the 100% deep-layer lake sediment, V. natans, H. verticillata, P. maackianus, P. malaia-nus and P. lucens had the highest relative growth rate (RGR) and biomass production, and so did for P. perfoliatus and M. verticillatum grown on the 100% surface lake sediment (C: 77.37 mg/g; N: 5.691 mg/g; P: 0.136 mg/g), and the sed-iment mixture of 50% surface lake sediment and 50% deep-layer lake sediment (C: 49.27 mg/g; N: 2.005 mg/g; P:0.131 mg/g) respectively. All the plant species did not grown well and got marginal biomass production on the 100%local soil (C: 22.06 mg/g; N: 0.327 mg/g; P: 0.231 mg/g). The results revealed that the sediment mixtures with interme-dium nutrients contents (C: 31.59—49.27 mg/g; N: 0.334—2.005 mg/g; P: 0.095—0.131 mg/g) were most beneficial to growth of submersed macrophytes, instead of the sediments with extremely higher or lower nutrient contents.