水下光照补偿对沉水植物苦草生长及主要生理指标的影响

Effects of underwater illumination compensation on growth and physiological indices of submerged macrophyte Vallisneria natans L.

水下有效光强是影响沉水植物群落生态恢复的主要限制因子。笔者通过设置不同水下人工光照补偿处理,研究在混浊水体中沉水植物苦草(Vallisneria natans L.)幼苗的生长和主要生理指标。结果表明:水下高光照补偿能够提高苦草幼苗的存活率,以及对幼苗的总生物量、平均单株生物量和产生的克隆株数量也具有一定的促进作用(相比对照处理分别显著增长了25%、220%、150%和160%)。通过水下光照补偿处理,苦草幼苗的叶片数、叶长及叶宽均有所增长(高补光处理相比对照处理分别增长了130%、100%和30%),并且随着光照强度的增强而增加。由于水体浊度的影响,对照组幼苗叶片的叶绿素含量减少,并且叶绿素a/b值降低。而通过水下补光,幼苗叶片的SOD酶和POD酶活性均有所升高,说明水下补光未能增加幼苗叶片内的活性氧。综上所述,水下光照补偿对苦草幼苗的存活、生长及叶片生理指标均有一定的促进作用。因此,水下光照补偿系统可以作为沉水植被生态恢复的有效方法。

Effective light intensity at underwater is the main limiting factor which affects the ecological restoration of submerged plant communities. We used artificial constructing underwater illumination compensation for Vallisneria natans L.in ecological restoration in turbid water（ 90 NTU）. We investigated the effect of different levels of the underwater illumination compensation on V. natans seedling survival,leaf morphological and physiological changes in metabolism mechanisms. The results showed that the high level of underwater illumination compensation increased the survival rate of V.natans seedlings,the total biomass of seedlings,the average biomass per plant and the number of clones（ significantly increased 25%,220%,150% and 160% compared with the control group,respectively）. Through the underwater illumination compensation,V. natans increased its seedling leaf number,leaf length and width,and this trend was enhanced by increasing illumination intensity（ high level of underwater illumination compensation group significantly increased 130%,100% and 30% compared with the control treatment,respectively）. Due to water turbidity,the control group decreased chlorophyll content in leaves and chl a /b ratio. Through the underwater illumination compensation,SOD and POD activities of seedlings were also increased,indicating that the underwater illumination compensation was unable to increase seedling leaves of reactive oxygen. In summary,the underwater illumination compensation could promote the V. natans seedling survival,growth and physiological indexes. Therefore,the underwater illumination compensation system should be an effective submerged vegetation restoration method.