Investigation of carbon dynamics in rhizosphere by synchrotron radiation-based Fourier transform infrared combined with two dimensional correlation spectroscopy.
Rhizosphere, formed via the input of root exudates, is one of the most dynamic biological interfaces on earth. Investigation of carbon dynamics in rhizosphere is thus crucial for the understanding of soil biogeochemical processes. Herein, synchrotron radiation-based Fourier transform infrared (SR-FTIR) combined with two dimensional correlation spectroscopy (2D-COS) was used to probe and identify the changes of chemical constituents and functional groups of organic carbon on the root/soil interface in rhizosphere of two plants [Leptochloa chinensis (L.) Nees and Cyperus rotundus L.]. The SR-FTIR results showed obviously heterogeneous distributions of functional groups in rhizosphere at microscale. Specifically, regardless of plant species, about 20-30 μm regions in rhizosphere can be affected by root activities. The peak area ratios of organic-OH and aliphatic-C to clay-OH on the root/soil interface in rhizosphere were 4.04-8.48 times higher than that in bulk soil, providing direct evidence of the organic carbon storage due to root activities. 2D-COS analysis suggested that the root activities induced the first adsorption or sequestration of newly organics (3350 cm-1) on the root/soil interface, followed by the destruction of clay-OH (3621 or 860 cm-1), leading to the release of mineral associated organics and nutrients (e.g., 1510 and 1150 cm-1) from the soil. These results can enlarge our knowledge on the concentration, distribution, and dynamics of organic carbon in rhizosphere at the microscale level and also the environmental behaviors and fate of other elements and contaminants that associated with organic carbon in rhizosphere. CAPSULE: SR-FTIR combined with 2D-COS can explore the distribution and dynamics of organic carbon on the root/soil interface in rhizosphere.
['Du|Haiyan|H|', 'Yu|Guanghui|G|', 'Guo|Mengjing|M|', 'Xu|Huacheng|H|']
D002244:Carbon D005583:Fourier Analysis D018517:Plant Roots D011827:Radiation D058441:Rhizosphere D012987:Soil D012988:Soil Microbiology D017550:Spectroscopy, Fourier Transform Infrared D013057:Spectrum Analysis D017356:Synchrotrons
Rhizosphere 2D-COS Root/soil interface Carbon storage SR-FTIR spectroscopy