Carbon, Nitrogen, and Phosphorus Allocation Strategy Among Organs in Submerged Macrophytes Is Altered by Eutrophication

Abstract

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.

Effects of Sediments Phosphorus Inactivation on the Life Strategies of Myriophyllum spicatum: Implications for Lake Restoration

“…Resource allocation is one of the central contents of modern ecological life history theory study [60], and plants adjust resource allocation to optimize resource capture [61,62]. The trade-off in resource allocation is mainly through the allocation of different nutrients within specific organs and the allocation of the same nutrient between organs [47,63]. The allocation of plant biomass between root and shoot (the ratio of belowground biomass to aboveground biomass) is an important indicator for the evaluation of plant life strategy change with environmental factors.…”

“…For instance, the reduced availability of nutrients in the sediments leads to the increase in biomass allocation to the root system resulting in a higher root to shoot ratio [45,46]. Additionally, plants decreased the allocation of N and P to stem with increasing water total nitrogen concentration [47]. Moreover, due to the species-specific life history strategies of plants, different environmental factors, such as the ambient nutrient contents, have different effects on the plants [48].…”

Variation in resource allocation strategies and environmental driving factors for different life‐forms of aquatic plants in cold temperate zones

“…The elemental composition and stoichiometric characteristics of aquatic plants are considered to be explained by species (taxon) identity and closely related to the environmental conditions where plants grow (Demars & Edwards, 2007; Gong et al., 2018; Li et al., 2013; Rao et al., 2020; Wang et al., 2015; Xia et al., 2014). For all aquatic plants, WD was the main factor affecting aquatic plant stoichiometry characteristics (Figure 4e).…”

“…Additionally, the scaling exponent is not significant between different topographic features (temperate and alpine) and grassland types (steppe and meadow; Yang et al., 2010). Different allometric relationships of submerged plants have been observed under different light environments, and the reflections vary by species (Fu et al., 2012; Rao et al., 2020). Biomass allocation in different life‐forms of aquatic plants remains to be studied.…”

“…In addition, under the influence of the aquatic environment, the morphological structure and physiological and ecological processes of aquatic plants are significantly different from those of terrestrial plants (Lacoul & Freedman, 2006; Sardans et al., 2011). Due to their diverse life‐forms and phenotypic plasticity, aquatic plants can use different organs to absorb nutrients (Carignan & Kalff, 1980), and the nutrient allocation strategies of different aquatic plant organs may be altered with changes in environmental conditions (Rao et al., 2020; Xu et al., 2020). It is important to research the above‐ground and below‐ground nutrient distribution strategies of aquatic plants.…”