Migration of (14)C in the paddy soil-to-rice plant system after (14)C-acetic acid breakdown by microorganisms below the plow layer.

Migration of (14)C derived from (14)C-acetic acid was examined by using soils sampled from paddies in four administrative areas in Japan (Aomori, Yamanashi, Ehime and Okinawa) and rice plant in a tracer experiment to understand the fate of (14)C in the paddy soil-to-rice plant system. The loss of (14)C radioactivity levels derived from (14)C-acetic acid was caused by soil microorganism breakdown. A part of the (14)C fixation to soil was caused by microbial assimilation into the fatty acid fraction. (14)C moved upward via two different types of (14)C dynamics in soil: quick movement upward; and constant but slow movement upward. (14)C was highly assimilated into the plant panicle and that was caused by the root-uptake and the transfer of (14)C. Migration of (14)C derived from (14)C-acetic acid relied heavily upon changes of chemical forms and characteristics of (14)C-compound as caused by microorganisms in soil. Copyright 2009 Elsevier Ltd. All rights reserved.