基质条件对苦草(Vallisneria natans)生长和形态特征的影响

通过模拟实验,对不同基质条件下苦草（Vallisneria natans）的形态特征、生物量积累及分配格局进行了研究.结果表明：（1）在营养盐较丰富的湖泥中,苦草的生物量、分株数量和匍匐茎总长度等指标显著大于粘土和沙土,也显著大于营养盐和有机质更高的河泥;（2）沙土中生长的苦草根系纤细,根系直径显著小于其他3种基质类型上的苦草;（3）河泥和沙土上生长的苦草叶绿素含量显著地低于湖泥和粘土上的苦草.因此,基质条件对苦草的生长和形态有较大的影响,苦草在一定程度上能够适应肥沃的基质条件,但当N、P、有机质含量过高时,苦草的生长受到抑制.

Effects of Sediments on the Growth and Morphology of Vallisneria natans

To determine the effect of different sediments on the morphology, biomass accumulation and allocation of Vallisneria natans, plants were planted in four soils: lake sediment, bank sediment, sandy loam and river sediment. After 7 weeks of growth, plants were dried, separated into aboveground and underground parts and weighed separately. The results showed that the biomass, ramet number and total stolon length of V. natans grown in the lake sediment were significantly higher than the plants grown in the sandy loam, bank sediment or river sediment. Compared with the plants grown in the other sediments, V. natans grown in sandy loam allocated more biomass to roots and had the highest ratio of root to shoot 0.48, but the root diameter of V. natans grown in sandy loam was lowest. Chlorophyll content of V. natans grown in sandy loam and river sediment were significantly lower than the plants grown in the lake sediment and bank sediment. The results suggested that sediment type played an important role in growth of V. natans. V. natans was able to grow normally under certain fertile sediments, but heavily eutrophic sediment as well as sterile sediment posed a negative effect on the growth of V. natans.