Stoichiometry of Carbon, Nitrogen and Phosphorus in Shrub Organs Linked Closely With Mycorrhizal Strategy in Northern China

Mycorrhizal strategies include mycorrhizal statuses and mycorrhizal types, which are important reflections of the functional characteristics of ecosystems. The stoichiometry of carbon, nitrogen, and phosphorus in plant organs is an important part of ecosystem functions, which has an important impact on the nutrient cycle of the ecosystem. The concentration of carbon, nitrogen, and phosphorus played a crucial role in ecosystem functioning and dynamics. The purpose of this study is to provide theoretical basis and data support for improving the properties of global terrestrial ecosystems by exploring the impact of mycorrhizal strategies on the stoichiometry of C, N, and P in different shrub organs. In this study, stoichiometric patterns of carbon (C), nitrogen (N) and phosphorus (P) in different shrub organs under different mycorrhizal status or types were analyzed at 725 samples across Northern China. Results showed that in different mycorrhizal status, the highest carbon concentration in shrub organs appeared in the facultatively mycorrhizal (FM) mycorrhizal status, and the highest nitrogen concentration appeared in the Non-mycorrhizal (NM) mycorrhizal status. Under different mycorrhizal types, the nitrogen concentration in the shrub organs under the arbuscular mycorrhiza (AM) mycorrhizal type was the highest, and the phosphorus concentration under the ecto-mycorrhiza (ECM) mycorrhizal type was the highest. In the OM or FM mycorrhizal status, the concentrations of C, N, and P in the stems and leaves increase with the increase of the concentrations of C, N, and P in the roots. In the NM mycorrhizal status, the N concentration in the stems and leaves increases with the increase of the N concentration in the roots. Under AM, AM+ECM, and ECM mycorrhizal type, the concentrations of C, N, and P are closely related in roots, stems and leaves. The content of plant nutrients in different organs is closely related. It turned out that mycorrhizal statuses or types are able to alter the allocation of C, N, and P in different organs, and the relationships of C, N, and P among different organs are able to present different trend with the varying of mycorrhizal statuses or types.

Mycorrhizal Status of Natural Stands of Pterocarpus erinaceus Poir. (Fabaceae) in Sudanian and Guinean Zones of West Africa

Background and Aims: The sylviculture of Pterocarpus erinaceus is still in its infancy due to lack of information on its biology. The aim of this study is to investigate its mycorrhizal status in order to better address its sylviculture. Place and Duration of Study: The study was performed on the field from May 2019 to December 2020 and data were analyzed at the laboratory from January to March 2021. Methodology: The frequency and intensity of mycorrhization were determined under a microscope after staining with trypan blue of fine roots collected at a depth of 20 cm under adult plants at 5 sites, 3 in the Guinean zone and 2 in the Sudanian zone in Togo. The spore density was obtained on soil samples taken at the same depth under the same trees. Results: Results indicate, without significant differences (P value = 0.166) among sites, and show that P. erinaceus is frequently mycorrhized (88% to 94%). However, there were significant differences (P value = 0.001) in spore densities between sites located in the Sudanian zone (16.53 ± 1.25 and 10.66 ± 0.71 spores per gram of soil – SPGS – respectively for the Fazao-Malfakassa and Oti-Kéran-Mandouri) and those located in the Guinean zone (4.54 ± 0.3, 2.93 ± 0.43 and 3.76 ± 1.01 SPGS respectively at Abdoulaye, Hahomegbe and Togodo). There are significant differences between mycorrhization intensities Togodo which has a mycorhization intensity of 33.52 ± 2.54 and other sites. The redundancy analysis carried out by taking into account substrates’ chemical characteristics shows that spore density remains low when phosphorus and nitrogen are important in the rhizosphere whereas the intensity of mycorhizations is low when PHKCl is high. Conclusion: This study provided evidence of mycorrhizal symbiosis in Pterocarpus erinaceus whether in the Sudanian or Guinean zone. Chemical quality of the growing substrate has an influence on parameters of mychorization. Further studies should therefore allow an assessment of the degree of dependence of this species with respect to the possible benefits associated with this symbiosis.