Stoichiometric homeostasis of vascular plants in the Inner Mongolia grassland

Abstract

Stoichiometric homeostasis, the degree to which an organism maintains its C:N:P ratios around a given species- or stage-specific value despite variation in the relative availabilities of elements in its resource supplies, is a key parameter in ecological stoichiometry. However, its regulation and role in affecting organismal and ecosystem processes is still poorly understood in vascular plants. We performed a sand culture experiment and a field nitrogen (N) and phosphorus (P) addition experiment to evaluate the strength of N, P and N:P homeostasis in higher plants in the Inner Mongolia grassland. Our results showed that homeostatic regulation coefficients (H) of vascular plants ranged from 1.93 to 14.5. H varied according to plant species, aboveground and belowground compartments, plant developmental stage, and overall plant nutrient content and N:P ratio. H for belowground and for foliage were inversely related, while H increased with plant developmental stage. H for N (H(N)) was consistently greater than H for P (H(P)) while H for N:P (H(N:P)) was consistently greater than H(N) and H(P). Furthermore, species with greater N and P contents and lower N:P were less homeostatic, suggesting that more homeostatic plants are more conservative nutrient users. The results demonstrate that H of plants encompasses a considerable range but is stronger than that of algae and fungi and weaker than that of animals. This is the first comprehensive evaluation of factors influencing stoichiometric homeostasis in vascular plants.

Growth rate, protein:RNA ratio and stoichiometric homeostasis of submerged macrophytes under eutrophication stress

“…Stoichiometric homeostasis coefficients (H N:P ) for submerged macrophytes in the study were less than animals but more than algae and fungi, which is in agreement with many studies for vascular plants (Sistla and Schimel, 2012;Sterner and Elser, 2002;Xing et al, 2015;Yu et al, 2011). Most of previous studies on stoichiometric homeostasis have made comparisons between autotrophs and heterotrophs (Persson et al, 2010), or among heterotrophs (Karimi and Folt, 2006;Villar-Argaiz et al, 2002), whereas comparisons across plant species are relatively lacking.…”

“…Most of previous studies on stoichiometric homeostasis have made comparisons between autotrophs and heterotrophs (Persson et al, 2010), or among heterotrophs (Karimi and Folt, 2006;Villar-Argaiz et al, 2002), whereas comparisons across plant species are relatively lacking. Yu et al (2011) and Xing et al (2015) made comparisons across vascular plants species in the Inner Mongolia grassland and across submerged macrophytes species in Yunnan plateau lakes, respectively. Yu et al (2010) reported that species with strong homeostasis are dominant and stable in the community, while ecosystems dominated by homeostatic taxa are productive and stable.…”

“…Generally, autotrophic organisms are considered to be nonhomeostatic or weakly homeostatic, whereas heterotrophs are thought to be strictly homeostatic (Persson et al, 2010;Sterner and Elser, 2002). Previous studies have also documented that stoichiometric homeostasis of plants is lower than that of animals and bacteria, but higher than that of plankton and fungi Sterner and Elser, 2002;Xing et al, 2015;Yu et al, 2011). Plant stoichiometry varies with growth rate and the surrounding environment (Ågren and Weih, 2012).…”

Human-induced nitrogen–phosphorus imbalances alter natural and managed ecosystems across the globe

“…The species that are stoichiometrically more homoeostatic than others tend to have higher biomass; and ecosystems dominated by more homoeostatic species tend to have higher productivity and stability 37 . Less homoeostatic species tend to have greater nitrogen and phosphorus concentrations and lower N:P ratio 38 . This suggests that fast shift rates of N:P ratio can be more detrimental for less homoeostatic species, with consequences for community composition and carbon cycling.…”

Nitrogen:phosphorous supply ratio and allometry in five alpine plant species

“…In this study, the leaf N and root P concentrations of grasses differed little between equivalent N:P supply ratios characterized by different absolute levels of the N and P supply (Figure 3e,h). This supports the view that grasses have a homeostatic regulation mechanism that adjusts N and P uptake to meet the minimum requirement for growth (Yu et al., 2011). In the composite forbs, however, the leaf and root N concentrations differed significantly between the 135:1 (N addition) and 135:1 (P reduction) treatments (Figure 3e,g).…”