Nutrient resorption efficiency of twigs is more vulnerable to warming than that of leaves of Cunninghamia lanceolata seedlings

Global warming is a major global issue that may affect nutrient cycling in terrestrial ecosystems. Plants usually employ the strategy of nutrient resorption to conserve resources. Over the past few decades, there has been widespread attention given to how warming affects the nutrient resorption efficiency (NuRE) in leaves. Twig is another important component of plant. The unique physiological characteristics of twig may make its NuRE response to warming different from that of leaf. However, there is insufficient knowledge regarding how warming affects NuRE in twigs.

We assessed the response of nutrient concentrations (nitrogen, phosphorus, potassium, calcium, and magnesium) and NuREs in leaves and twigs to warming, by using plant samples (Cunninghamia lanceolata) from a manipulative field warming experiment (+ 5 °C).

The nutrient concentrations and NuREs of leaves remained unchanged under warming. In contrast, warming significantly decreased nitrogen concentration (− 13%) and increased calcium (+ 21%) and magnesium (+ 44%) concentrations in mature twigs. Warming significantly decreased NRE (− 10%), KRE (− 15%), and CaRE (− 7%), and increased MgRE (+ 12%) in twigs. It was also found that warming decreased the water content of twigs, and there were significant negative correlations between NuREs and nutrients in senesced organs.

The nutrient concentrations and NuRE of twigs are more vulnerable to warming than those of leaves. The regulation of NuRE response to warming is influenced by water and nutrients. Incorporating plant twig NuRE into nutrient cycling modeling and ecosystem productivity predictions may improve the accuracy of predictions under future warming conditions.