Leaf and root nutrient concentrations and stoichiometry along aridity and soil fertility gradients

Guofang Liu, Xuehua Ye, Zhenying Huang*, Ming Dong, Johannes H.C. Cornelissen

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

Questions: Leaf nitrogen (N), phosphorus (P) concentrations and N : P ratio have been extensively studied along environmental gradients, but whether and how leaves and roots show similar responses to climatic and fertility gradients is little studied. Also, the responses of leaf and root N and P in different plant functional types (PFT; legumes, grasses, forbs and shrubs) to environmental gradients are poorly known. We examined the following two hypotheses: (a) P concentration and N : P ratios in leaves or fine roots would not be modulated by soil N for legumes while they would be for non-legume PFTs; (b) Species turnover would have stronger influence on the responses of N and P concentrations and N : P ratios of plant tissues along aridity and soil fertility gradients than intraspecific variation. Study site: Ordos Plateau, China. Methods: We collected samples of leaf and fine roots covering 95 species of 28 families across 17 sites affiliated to four vegetation types on the dry Ordos Plateau of North China and compared variations in N and P concentrations and N : P ratios in both leaves and fine roots among PFTs. Results: We found that legumes had higher N concentrations in leaves and fine roots than the non-legume PFTs. Leaf and fine root P and N : P ratios increased with increasing soil N for most non-legume PFTs, but the relationships were decoupled for legumes. Species turnover had a stronger contribution to these relationships of N and P in leaves and fine roots along aridity and soil N gradients than intraspecific variation. Conclusions: When modeling vegetation nutrient stocks and cycling, the predictive power could be improved by taking into account not only influences of soil fertility but also of climate on leaf and root tissue N and soil N on tissue P and N : P ratio, especially for non-legume functional types.

Original languageEnglish
Pages (from-to)291-300
Number of pages10
JournalJournal of Vegetation Science
Volume30
Issue number2
Early online date4 Jan 2019
DOIs
Publication statusPublished - Mar 2019

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Keywords

  • aridity index gradient
  • dryland
  • ecological stoichiometry
  • fine root
  • intraspecific variation
  • nitrogen fixer
  • plant functional type
  • soil fertility gradient
  • species turnover

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