The framework of ecological stoichiometry, concerning the balance of multielement in ecological interactions, is largely limited to nitrogen (N) and phosphorus (P).Beyond these two, all other essential elements are also required by plants and involved in ecological functioning and progresses. Considerable variability in element concentrations could occur in plants, although plants can maintain relatively constant nutrient concentrations in environments with varied nutrient availability (stoichiometric homeostasis). A better understanding on the concentrations, variability and stoichiometric homeostatic of all essential elements are critical to achieve a broad perspective on plant stoichiometry. Here, we attempt to ask : 1)what is the pattern of concentrations, variability and stoichiometric homeostasis of diverse elements in grassland plants? 2)how do the element homeostasis and multielement composition differ among species? In the present study, three plant species (Leymus chinensis, Cleistogenes squarrosa and Chenopodium glaucum, representing different plant functional types in Inner Mongolia grassland) were cultured to analyze interspecies differences in multielement stoichiometry. We investigated the pattern of ten elements including macroelements (N, P, potassium (K), sulfur (S)), microelements (iron (Fe), zinc (Zn), boron (B), molybdenum (Mo)), and non-essential elements(cadmium (Cd) and lead (Pb)).
Results/Conclusions
Across these ten elements we studied, homeostasis coefficient (H) was significantly positively correlated with element concentration and negatively correlated with coefficient of variation within each species. It indicated that those abundant elements have stronger stoichiometric homeostasis and are less variable under changed nutrients supply in plants. For all individual elements (except Pb), homeostatic regulation strength was highest in dominant plant Leymus chinensis and lowest in rare plant Chenopodium glaucum. There were also clear differences in multielement composition among grassland plant species. The species specific stoichiometric homeostasis and multielement composition in grassland highlighted the importance of trace elements in characterizing taxonomic identity. Our findings may help us to approach a synthetic theory of ecological stoichiometry and a comprehensively understanding on plant nutrition in a changing world.