Data supporting: Differential responses of nitrogen uptake strategies by dominant woody species to tunnel excavation in karst and non-karst forests of Southwest China
Description
Dataset for “Differential responses of nitrogen uptake strategies by dominant woody species to tunnel excavation in karst and non-karst forests of Southwest China”, comprising soil physicochemical properties, plant nitrogen uptake rates and the relative contributions of different nitrogen forms, as well as root functional traits.
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In August 2023, a labeled hydroponic field experiment was conducted on the target plants. A 15N hydroponic method was used to measure the uptake rates of NH4+, NO3- and organic N by plants, and the contribution of different N forms to total N uptake was quantified. Over 90% of the soil N exists in soil organic matter, with 20-40% of the organic N potentially present in the form of amino acid N (Näsholm et al., 2009; Näsholm and Persson, 2001). Glycine, a common low-molecular-weight amino acid in soils that is rarely utilized by microorganisms, was chosen as the organic N source in this study (Liu et al., 2017; Liu et al., 2020; Ren et al., 2023). To provide the roots with a 'selection' of N forms, we prepared four N mixture solutions, each containing NH4+, NO3- and glycine at a concentration of 30 μmol N L-1 for each N form. The N concentration in the prepared solution was equivalent to 1/1000 of the total N content in the soil, with the aim of minimizing fertilization effects. Three of these solutions were labeled with 15N (the isotopic labels were 15NH4NO3, NH415NO3 and C2H515NO2, with abundances of 10%, 10% and 99%, respectively), where only one N form in each solution was labeled with 15N, and the other two forms remained unlabeled (i.e., 15NH4NO3+C2H5NO2, NH415NO3+C2H5NO2 and NH4NO3+C2H515NO2). All N mixtures contained 10 mg L-1 ampicillin to reduce microbial activity and prevent glycine decomposition. Additionally, 0.2 mmol L-1 of CaCl2 was added to each solution to maintain root function stability and integrity (Warren and Adams, 2007). The four prepared solutions were aliquoted into 15 mL centrifuge tubes and stored at 4°C for use in field tracing within one week.
Institutions
- Southwest UniversityChongqing, Chongqing