黑大豆根系对溶液甲醛的吸收及其代谢产物分析

Absorption of formaldehyde by black soybean roots and products of formaldehyde metabolism

本研究考查在2、4和6 mmol·L^(-1)甲醛(HCHO)溶液中处理的‘丹波’黑大豆(Glycine max cv.Tamba)根系对HCHO的吸收与代谢产物。结果表明,在48 h处理期内根系对HCHO的吸收与时间的关系为指数函数。活体根系吸收HCHO对其去除的贡献率分别为30.1%、26.7%和23.0%,显著大于死根系对HCHO的吸附作用,这一结果表明活体根中发生了HCHO代谢作用。碳-13核磁共振(^(13)C-NMR)分析表明,根系吸收的H^(13)CHO首先被氧化为H^(13)COOH;在H^(13)CHO处理0~4 h期间,H^(13)COOH被同化为草酸、甘氨酸、天冬酰胺、谷氨酰胺和丝氨酸,在4~48 h期间,这些有机酸被转化为苹果酸、柠檬酸、异柠檬酸和葡萄糖。4和6 mmol·L^(-1) H^(13)CHO处理2 h的根系中代谢产物种类与2 mmol·L^(-1)处理的相似,但每种代谢产物产量显著提高。

It has been shown that plant roots have considerable contribution to formaldehyde（HCHO）removal in bioreactors,which is associated with HCHO assimilation by roots.This study investigates HCHO absorption and metabolites in the roots of‘Tamba’black soybean（Glycine max）treated in 2,4 and 6 mmol·L^-1 HCHO solutions.The results show that the relationship between HCHO absorption and treatment time over a 48 h treatment period fits an exponential function.The contribution（30.1%,26.7%and 23.0%）of HCHO absorption by living roots to HCHO removal were significantly greater than that of the HCHO adsorption by dead roots after treatment for 48 h.The evidence suggests the presence of HCHO metabolism is in the living roots.^13C-NMR（carbon-13 nuclear magnetic resonance）analyses indicated that,in 2 mmol·L^-1 H^13CHO treated-roots,the absorbed H^13CHO was first oxidized to H^13COOH,which was then mainly converted to oxalate,glycine,asparagine,glutamine and serine during the 0-4 h treatment period.During the 4-48 h treatment period,these organic acids were converted to malate,citrate,isocitrate and glucose.The metabolite types in 4 and 6 mmol·L^-1H^13CHO treated-roots for 2 h were similar to those in 2 mmol·L^-1 H^13CHO treated-roots but the yield of each metabolite was significantly increased.