The allocation of limiting elements among plant organs is an important aspect of the adaptation of plants to their ambient environment. Although eutrophication can extremely alter light and nutrient availability, little is known about nutrient partitioning among organs of submerged macrophytes in response to eutrophication. Here, we analyzed the stoichiometric scaling of carbon (C), nitrogen (N), and phosphorus (P) concentrations among organs (leaf, stem, and root) of 327 individuals of seven common submerged macrophytes (three growth forms), sampled from 26 Yangtze plain lakes whose nutrient levels differed. Scaling exponents of stem nutrients to leaf (or root) nutrients varied among the growth forms. With increasing water total N (WTN) concentration, the scaling exponents of stem C to leaf (or root) C increased from <1 to >1, however, those of stem P to root P showed the opposite trend. These results indicated that, as plant nutrient content increased, plants growing in low WTN concentration accumulated leaf C (or stem P) at a faster rate, whereas those in high WTN concentration showed a faster increase in their stem C (or root P). Additionally, the scaling exponents of stem N to leaf (or root) N and stem P to leaf P were consistently large than 1, but decreased with a greater WTN concentration. This suggested that plants invested more N and P into stem than leaf tissues, with a higher investment of N in stem than root tissues, but eutrophication would decrease the allocation of N and P to stem. Such shifts in plant nutrient allocation strategies from low to high WTN concentration may be attributed to changed light and nutrient availability. In summary, eutrophication would alter nutrient allocation strategies of submerged macrophytes, which may influence their community structures by enhancing the competitive ability of some species in the process of eutrophication.

植物器官之间限制元素的分配是植物适应周围环境的一个重要方面。尽管富营养化会极大地改变光和养分的可用性，但人们对沉水植物器官之间养分分配对富营养化的响应知之甚少。在这里，我们分析了 7 种常见沉水植物（三种生长形式）的 327 个个体的器官（叶、茎和根）中碳 (C)、氮 (N) 和磷 (P) 浓度的化学计量比例，这些植物采样自长江平原26个湖泊营养水平存在差异。茎养分与叶（或根）养分的比例指数因生长形式而异。随着水体全氮（WTN）浓度的增加，茎C到叶（或根）C的标度指数从<1 id=205>1增加，而茎P到根P的标度指数则呈现相反的趋势。这些结果表明，随着植物养分含量的增加，在低WTN浓度下生长的植物以更快的速度积累叶C（或茎P），而在高WTN浓度下生长的植物其茎C（或根P）则表现出更快的增加。此外，茎 N 与叶（或根）N 和茎 P 与叶 P 的标度指数始终大于 1，但随着 WTN 浓度的增加而减小。这表明植物向茎中投入的氮和磷多于叶组织，茎中氮的投入高于根组织，但富营养化会减少氮和磷向茎的分配。植物养分分配策略从低 WTN 浓度到高浓度的转变可能归因于光照和养分可用性的变化。 综上所述，富营养化会改变沉水植物的养分分配策略，从而可能通过增强某些物种在富营养化过程中的竞争能力来影响其群落结构。