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Investigating Short‐Term Carbon Flows in the Rhizospheres of Different Plant Species, Using Isotopic Trapping
Author(s) -
Cheng Weixin,
Coleman David C.,
Carroll C. Ronald,
Hoffman Carol A.
Publication year - 1994
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1994.00021962008600050007x
Subject(s) - rhizosphere , agronomy , biology , soil respiration , respiration , loam , botany , trapping , soil water , ecology , genetics , bacteria
Many difficulties exist in studying rhizosphere carbon flows in situ because of limited methodologies. Current photosynthate allocation to root respiration, rhizosphere microbial respiration and soluble root exudates in the rhizospheres of winter wheat ( Triticum aestivum L.), tall fescue ( Festuca arundinacea Schreb.), and buffalo gourd ( Cucurbita foetidissima HBK) were investigated using an isotopic trapping procedure. Plants were grown in containers with 165 g of sandy clay loam soil for 3 wk before the time of 14 C pulse labeling. Most root exudates were utilized by the microbes in the immediate rhizosphere and released as 14 CO 2 . Only a small amount of exudates was found in the bulk soil (2.7, 2.5, and 3.7% in the control treatments of wheat, tall fescue, and buffalo gourd respectively). The isotopic trapping mechanism was valid for all three species even though the patterns of total rhizosphere respiration (measured as total 14 CO 2 ) rates during the initial 8 h of tracing for the three plant species were different in peak time and peak height. The isotopic trapping procedure can be used in rhizosphere studies for various plant species in principle. Some modifications to the procedure may be needed for different plant‐soil systems.