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A novel method for separating root‐derived organic compounds from root respiration in non‐sterilized soils
Author(s) -
Kuzyakov Yakov,
Siniakina Svetlana V.
Publication year - 2001
Publication title -
journal of plant nutrition and soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 1436-8730
DOI - 10.1002/1522-2624(200110)164:5<511::aid-jpln511>3.0.co;2-t
Subject(s) - rhizosphere , respiration , chemistry , elution , lolium perenne , soil water , botany , environmental chemistry , horticulture , chromatography , biology , soil science , environmental science , bacteria , poaceae , genetics
A novel method of separating exudates from root respiration in non‐sterilized soils has been developed. The method is based on a simultaneous elution of exudates from rhizosphere and the blowout of CO 2 originating from root respiration. The innovation of the method lies in the function of a membrane pump to drive the movement of air and simultaneously the circulation of water according to the Siphon principle. The separation method was tested by means of 14 C pulse labeling of Lolium perenne to track the C dynamics in the production of rhizosphere CO 2 and of exudates, which were eluted. The total 14 C activity of rhizosphere CO 2 and of eluted exudates was found to be 8.5 % and 2.3 % of total assimilated 14 C, respectively. Thus, at least 19 % of root‐derived C can be accounted to root exudation. However, the suggested Siphon method underestimates the amount of exudates and shows only a minimum of organic substances exuded by roots. The diurnal dynamics of exudation was detected, but no significant day‐night changes were measured in root and microbial respiration. Tight coupling of assimilation with exudation, but not with root and microbial respiration, was observed. The advantages, shortcomings, and possible applications of the Siphon method are discussed.