Resumo

YANG, G et al. Nitrogen deposition influences the response of Potentilla tanacetifolia to phosphorus addition. Phyton (B. Aires) [online]. 2016, vol.85, n.1, pp.100-107. ISSN 1851-5657.

Phosphorus is an essential macronutrient for all living plants and plant production. Simultaneously, atmospheric nitrogen deposition also affects plant productivity at a global scale. However, few studies have investigated how plants respond to P addition while simultaneously considering N deposition. We investigated plant biomass, nutrient status and stoichiometric ratios on Potentilla tanacetifolia in response to P fertilization under contrasting N addition rates in a typical meadow steppe in Inner Mongol ia, China. Aboveground biomass of P. tanacetifolia increased under increasing levels of P fertilization under conditions of N addition. However, there was no significant change in biomass when only phosphorus was added. Plant leaf and stem P concentrations increased linearly with P addition when there was no N addition. Our results suggest that increased plant P nutrition under P addition will not turn into plant growth enhancement unless N demands are also satisfied. Nitrogen addition significantly increased leaf N concentrations, and leaf and seed N:P ratios, when there was no P fertilization. Nevertheless, the effects of N addition were weakened, and eventually disappeared when P fertilization rates increased. This indicates that N-induced alterations of the plant nutrition status and stoichiometric ratios were P availability-dependent. Overall, our results suggest that multiple-nutrient constraints and their interactions must be considered when assessing plant nutrient and growth responses to nutrient enrichment.

Palavras-chave : Nitrogen; Phosphorus; N: P ratio; Plant organs.

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