蓝藻胁迫条件下不同基质类型对苦草和伊乐藻生长的影响

Effects of substrate on Vallisneria natans and Elodea canadensis under cyanobacterial stress conditions

为探讨蓝藻胁迫条件下沉水植物生长与基质营养含量的关系,研究了添加相同含量蓝藻后2种不同基质(较贫瘠的黄色粘土和较肥沃的黑色淤泥)对苦草和伊乐藻2种沉水植物生长的影响。结果表明:与伊乐藻相比,苦草的生物量在粘土条件下高于淤泥条件,而基质类型对伊乐藻生物量没有显著影响;苦草的最大叶片长度(用于表征株高)、无性系新株数目及其干物质重和伊乐藻的株高、分株数目和分枝干物质重也是在粘土条件下高于淤泥条件;苦草的最大根长在粘土条件下显著高于淤泥条件(p<0.05)。研究结果表明在蓝藻胁迫的条件下,高营养含量的基质不利于沉水植物的生长,并且对根生型沉水植物苦草的影响要大于假根沉水植物伊乐藻。

In order to investigate the relationships between the growth of submerged macrophytes and the nutrients condition of their substrates under cyanobactefial stress conditions, mesocosms were constructed to study the effects of two different substrates （the yellow clay with relative poor nutrient and the black sediment with rich nutrient） on the growth of two submersed aquatic macrophytes, i.e. Vallisneria natans and F, lodea canadensis after adding the same biomass of fresh cyanobacteria to each mesocosm. The results showed that the hiomass of V. natans in the yellow clay was higher than that in black sediment as compared to E. Canadensis. Meanwhile, the maximum leaf length and the number of the new ramets were higher in the yellow clay, and the maximum root length was significantly longer in the yellow clay than that in the black sediment. As for the E. Canadensis, there was no significant difference in hiomass between the two substrates, but the length, the number and the dry biomass of the new branches orE. Canadensis were larger in the yellow clay. All those results suggest that under cyanobacterial stress conditions, the substrates with the high nutrition level is not favorable to the growth of submerged macrophytes; moreover, their effects on the rooted submerged macrophyte V. natans were larger than those on the rhizoid submerged macrophyte E. Canadensis.