RESUMO
The impacts of enhanced nitrogen (N) deposition on the global forest carbon (C) sink and other ecosystem services may depend on whether N is deposited in reduced (mainly as ammonium) or oxidized forms (mainly as nitrate) and the subsequent fate of each. However, the fates of the two key reactive N forms and their contributions to forest C sinks are unclear. Here, we analyze results from 13 ecosystem-scale paired 15N-labelling experiments in temperate, subtropical, and tropical forests. Results show that total ecosystem N retention is similar for ammonium and nitrate, but plants take up more labelled nitrate ([Formula: see text]%) ([Formula: see text]) than ammonium ([Formula: see text]%) while soils retain more ammonium ([Formula: see text]%) than nitrate ([Formula: see text]%). We estimate that the N deposition-induced C sink in forests in the 2010s is [Formula: see text] Pg C yr-1, higher than previous estimates because of a larger role for oxidized N and greater rates of global N deposition.
Assuntos
Compostos de Amônio/análise , Sequestro de Carbono/fisiologia , Recuperação e Remediação Ambiental , Florestas , Nitratos/análise , Árvores/metabolismo , Meio Ambiente , Isótopos de Nitrogênio/química , Óxidos de Nitrogênio/análise , Solo/químicaRESUMO
The complete mitochondrial genome of Tamiops swinhoei has been determined in this study. It is 16,513 bp in size and consists of 2 rRNA genes, 13 protein-coding genes, 22 tRNA genes and one non-coding region (D-loop). The overall base composition of the heavy strand of the T. swinhoei mitochondrial genome is A: 32.63%, T: 28.67%, C: 26.33% and G: 12.37%. The alignment of the Tamiops species control regions exhibited high genetic variability and rich A + T content (63.42%).
Assuntos
Genoma Mitocondrial , Sciuridae/genética , Animais , Códon , DNA Mitocondrial/química , DNA Mitocondrial/isolamento & purificação , DNA Mitocondrial/metabolismo , Proteínas de Peixes/química , Proteínas de Peixes/genética , Proteínas de Peixes/metabolismo , RNA Ribossômico/química , RNA Ribossômico/isolamento & purificação , RNA Ribossômico/metabolismo , RNA de Transferência/química , RNA de Transferência/isolamento & purificação , RNA de Transferência/metabolismo , Análise de Sequência de DNARESUMO
PREMISE OF THE STUDY: Microsatellite loci were developed for Cephalotaxus oliveri, an endemic and endangered conifer in China, which will allow assessment of the levels of genetic diversity and a means to understand the genetic consequences of habitat fragmentation. METHODS AND RESULTS: Using the Fast Isolation by AFLP of Sequences COntaining (FIASCO) Repeats protocol, 19 microsatellite loci were identified in C. oliveri, 13 of which were polymorphic within a sample of 52 individuals representing five natural populations. The actual number of alleles per locus ranged from one to five. Twelve polymorphic loci were also successfully amplified in C. fortunei. CONCLUSIONS: These microsatellite loci will provide a useful tool for further investigating genetic variation in natural populations of C. oliveri, which will inform future conservation and management strategies. Additionally, cross-amplification in C. fortunei suggested the potential utility of these loci in this and other congeneric species.