Read D B, Bengough A G, Gregory P J, Crawford J W, Robinson D, Scrimgeour C M, Young I M, Zhang K, Zhang X
Department of Soil Science, The University of Reading, Whiteknights, PO Box 233, Reading, RG6 6DW.
Soil-Plant Dynamics Unit, Scottish Crop Research Institute, Dundee, DD2 5DA.
New Phytol. 2003 Feb;157(2):315-326. doi: 10.1046/j.1469-8137.2003.00665.x.
• Plant root mucilages contain powerful surfactants that will alter the interaction of soil solids with water and ions, and the rates of microbial processes. • The lipid composition of maize, lupin and wheat root mucilages was analysed by thin layer chromatography and gas chromatography-mass spectrometry. A commercially available phosphatidylcholine (lecithin), chemically similar to the phospholipid surfactants identified in the mucilages, was then used to evaluate its effects on selected soil properties. • The lipids found in the mucilages were principally phosphatidylcholines, composed mainly of saturated fatty acids, in contrast to the lipids extracted from root tissues. In soil at low tension, lecithin reduced the water content at any particular tension by as much as 10 and 50% in soil and acid-washed sand, respectively. Lecithin decreased the amount of phosphate adsorption in soil and increased the phosphate concentration in solution by 10%. The surfactant also reduced net rates of ammonium consumption and nitrate production in soil. • These experiments provide the first evidence we are aware of that plant-released surfactants will significantly modify the biophysical environment of the rhizosphere.
• 植物根系黏液含有强大的表面活性剂，这些表面活性剂会改变土壤固体与水和离子的相互作用以及微生物过程的速率。
• 通过薄层色谱法和气相色谱 - 质谱分析法对玉米、羽扇豆和小麦根系黏液的脂质组成进行了分析。然后使用一种市售的磷脂酰胆碱（卵磷脂），其化学性质与在黏液中鉴定出的磷脂表面活性剂相似，来评估其对选定土壤性质的影响。
• 与从根组织中提取的脂质相比，黏液中发现的脂质主要是磷脂酰胆碱，主要由饱和脂肪酸组成。在低张力土壤中，卵磷脂分别使土壤和酸洗砂在任何特定张力下的含水量降低了多达10%和50%。卵磷脂减少了土壤中磷酸盐的吸附量，并使溶液中的磷酸盐浓度增加了10%。该表面活性剂还降低了土壤中铵的消耗净速率和硝酸盐的产生速率。
• 这些实验提供了我们所知的首个证据，即植物释放的表面活性剂会显著改变根际的生物物理环境。
