Yan Xue, Yu Dan, Li Yong-Ke
College of Life Sciences, Wuhan University, Wuhan 430072, PR China.
Chemosphere. 2006 Jan;62(4):595-601. doi: 10.1016/j.chemosphere.2005.06.018. Epub 2005 Aug 3.
An approximately four months long glasshouse experiment was conducted to examine the effects of elevated carbon dioxide (CO(2)) concentration (1,000 +/- 50 micromol mol(-1)) in the atmosphere on biomass accumulation and allocation pattern, clonal growth and nitrogen (N), phosphorus (P) accumulation by the submerged plant Vallisneria spinulosa Yan. Elevated CO(2) significantly increased V. spinulosa total fresh biomass ( approximately 130%) after 120 days, due to more biomass accumulation in all morphological organs than in those at ambient CO(2) (390 +/- 20 micromol mol(-1)). About 75% of the additional total biomass at elevated CO(2) was accounted for by leaf and rhizome (above ground) biomass and only 25% of it belonged to root and turion (below ground). However, the turions biomass exhibited a greater increase rate than that of organ above ground, which caused reduction in the above/below ground biomass ratio. The clonal growth of V. spinulosa responded positively to elevated CO(2). The number of primary ramets increased up to 1.4-folds at elevated CO(2) and induced a dense growth pattern. For nutrients absorption, concentration of N in leaf and in turion was significantly (p <or= 0.05) reduced by 13.4% and by 15.7% in elevated CO(2) and were not affected in both root and rhizome. Percent P, in contrast, was significantly (p <or= 0.05) enhanced in all of the organs, ranging from 35% to 147%, except for turion. Compared with those in ambient CO(2), the mean accumulation per ramet of N and P significantly higher in elevated CO(2). These results showed that elevated CO(2) could promote submerged plant biomass accumulation, and it should be an adaptive strategy for clonal plants to increase the nutrient absorption efficiency of root and reproduce more clonal ramets to exploit enough resources to match with higher growth in elevated CO(2).
进行了一项为期约四个月的温室实验，以研究大气中二氧化碳（CO₂）浓度升高（1000±50 μmol mol⁻¹）对沉水植物刺苦草（Vallisneria spinulosa Yan）生物量积累与分配模式、克隆生长以及氮（N）、磷（P）积累的影响。120天后，二氧化碳浓度升高显著增加了刺苦草的总鲜生物量（约130%），这是因为与环境二氧化碳浓度（390±20 μmol mol⁻¹）下相比，所有形态器官中的生物量积累更多。在二氧化碳浓度升高时，额外总生物量的约75%由叶片和根状茎（地上部分）生物量构成，只有25%属于根和块茎（地下部分）。然而，块茎生物量的增加速率高于地上器官，这导致地上/地下生物量比降低。刺苦草的克隆生长对二氧化碳浓度升高有积极响应。在二氧化碳浓度升高时，一级分株数量增加至1.4倍，并形成密集的生长模式。对于养分吸收，二氧化碳浓度升高时，叶片和块茎中的氮浓度显著降低（p≤0.05），分别降低了13.4%和15.7%，而根和根状茎中的氮浓度不受影响。相比之下，除块茎外，所有器官中的磷含量均显著增加（p≤0.05），增幅在35%至147%之间。与环境二氧化碳浓度下相比，二氧化碳浓度升高时每个分株的氮和磷平均积累量显著更高。这些结果表明，二氧化碳浓度升高可促进沉水植物生物量积累，这应该是克隆植物的一种适应性策略，即提高根系养分吸收效率并繁殖更多克隆分株，以获取足够资源来适应二氧化碳浓度升高时更高的生长需求。
