Garland J L, Levine L H, Yorio N C, Hummerick M E
Dynamac Corporation, Mail Code DYN-3, Kennedy Space Center, FL 32899, USA.
Water Res. 2004 Apr;38(8):1952-62. doi: 10.1016/j.watres.2004.01.005.
Anionic (sodium laureth sulfate, SLES), amphoteric (cocamidopropyl betaine, CAPB) and nonionic (alcohol polyethoxylate, AE) surfactants were added to separate nutrient film technique (NFT) hydroponic systems containing dwarf wheat (Triticum aestivum cv. USU Apogee) in a series of 21 day trials. Surfactant was added either in a (1). temporally dynamic mode (1-3 g surfactant m(-2) growing area d(-1)) as effected by automatic addition of a 300 ppm surfactant solution to meet plant water demand, or (2). continuous mode (2 g surfactant m(-2) growing area d(-1)) as effected by slow addition (10 mLh(-1)) of a 2000 ppm surfactant solution beginning at 4d after planting. SLES showed rapid primary degradation in both experiments, with no accumulation 24 h after initial addition. CAPB and AE were degraded less rapidly, with 30-50% remaining 24 h after initial addition, but CAPB and AE levels were below detection limit for the remainder of the study. No reductions in vegetative growth of wheat were observed in response to SLES, but biomass was reduced 20-25% with CAPB and AE. Microbial communities associated with both the plant roots and wetted hardware surfaces actively degraded the surfactants, as determined by monitoring surfactant levels following pulse additions at day 20 (with plants) and day 21 (after plant removal). In order to test whether the biofilm communities could ameliorate phytotoxicity by providing a microbial community acclimated for CAPB and AE decay, the continuous exposure systems were planted with wheat seeds after crop removal at day 21. Acclimation resulted in faster primary degradation (>90% within 24h) and reduced phytotoxicity. Overall, the studies indicate that relatively small areas (3-5m(2)) of hydroponic plant systems can process per capita production of mixed surfactants (5-10 g x person(-1)d(-1)) with minimal effects on plant growth.
在一系列为期21天的试验中，将阴离子型（月桂醇聚醚硫酸酯钠，SLES）、两性离子型（椰油酰胺丙基甜菜碱，CAPB）和非离子型（脂肪醇聚氧乙烯醚，AE）表面活性剂添加到分别装有矮秆小麦（普通小麦品种USU Apogee）的营养液膜技术（NFT）水培系统中。表面活性剂的添加方式有两种：（1）时间动态模式（1 - 3克表面活性剂/平方米种植面积/天），通过自动添加300 ppm的表面活性剂溶液来满足植物的需水量；（2）连续模式（2克表面活性剂/平方米种植面积/天），从种植后第4天开始，以缓慢添加（10毫升/小时）2000 ppm表面活性剂溶液的方式进行。在两个实验中，SLES均显示出快速的初级降解，初始添加后24小时内无积累。CAPB和AE的降解速度较慢，初始添加后24小时仍有30 - 50%残留，但在研究的剩余时间里，CAPB和AE的水平低于检测限。未观察到SLES对小麦营养生长有降低作用，但CAPB和AE使生物量降低了20 - 25%。通过监测第20天（有植物时）和第21天（移除植物后）脉冲添加表面活性剂后的水平，确定与植物根系和湿润硬件表面相关的微生物群落能积极降解表面活性剂。为了测试生物膜群落是否可以通过提供适应CAPB和AE降解的微生物群落来改善植物毒性，在第21天作物移除后，将连续暴露系统种植小麦种子。适应导致更快的初级降解（24小时内>90%）并降低了植物毒性。总体而言，研究表明相对较小面积（3 - 5平方米）的水培植物系统能够处理人均混合表面活性剂产量（5 - 10克/人/天），且对植物生长的影响最小。
