咸淡交替灌溉对克隆植物大米草生长繁殖和生物量分配的影响

通过温室模拟控制实验,研究了咸淡交替灌溉处理对外来克隆植物大米草(Spartina anglica)形态性状、克隆生长、生物量积累及分配格局的影响。实验共设6种浇灌处理:单一淡水灌溉(D)、单一咸水浇灌(X)、淡咸交替灌溉(DX)、咸淡交替灌溉(XD)、淡咸淡交替灌溉(DXD)和咸淡咸交替灌溉(XDX)。结果表明:DX处理条件下,大米草株高、叶片数及根长均达到最高;克隆数最多,且显著高于X、DXD和XDX处理;芽数及根状茎总长均显著大于XDX处理;在DX和D处理下,地上生物量、根系生物量、地下生物量和总生物量均显著高于其它处理。这表明作为滨海盐沼植物,大米草种群比较适应淡咸水交替环境,单一的咸水,以及过度的咸淡转换均不利于大米草的生长繁殖与生物量积累,而淡咸水交替过程的失序可能是引起我国大米草种群衰退的重要原因。

Plant growth, reproduction and biomass allocation in response of clonal plant Spartina anglica to alternative irrigation of fresh and saline water

Results of the greenhouse experiment showed that fresh and saline water alternation irrigation had significant effects on morphological traits, clonal characteristics, biomass accumulation and biomass allocation patterns of Spartina anglica coming from the Xinyang Harbor in Jiangsu Province, China. Six irrigation treatments were set up in our experiments including single irrigation with freshwater (D) or salt water(X), single alternating irrigation with freshwater and saltwater (DX and XD) and double alternating irrigation (DXD and XDX). With the DX treatment, plant height, number of leaves and the length of roots reached the maximal value. Meanwhile, the number of ramets was significantly higher than those of X, DXD and XDX treatments (P < 0.05); the number of buds and total rhizome length were significantly higher than those of XDX treatment (P < 0.05). Roots biomass, below\|ground biomass and total biomass under DX and D treatments were both significantly higher than those of other treatments (P < 0.05). The results showed that S. anglica populations grew better with the DX treatment, which did good to sustain and regenerate the population. Not only X treatment but also excessive alternative irrigation of fresh and saline water worked against the growth and biomass accumulation of Spartina anglica. The results indicated that the frequent change in fresh and saline water for S. anglica vegetation area would explain the decline of its populations over its range.