Bushey Joseph T, Small Mitchell J, Dzombak David A, Ebbs Stephen D
Department of Civil and Environmental Engineering, Syracuse University, Syracuse, New York, USA.
Int J Phytoremediation. 2006;8(1):45-62. doi: 10.1080/15226510500507052.
A plant uptake model is applied to describe free cyanide and ferrocyanide transport and fate in willow (Salix eriocephala var. Michaux) grown in hydroponics. The model is applied to experimental data to determine best-fit parameter values, their associated uncertainty, and their relative importance to field-scale phytoremediation applications. The fitted model results, using least-squares optimization of the observed log concentrations, indicate that free cyanide volatilization from leaf tissue and free cyanide cell wall adsorption were negligible. The free cyanide maximum uptake rate and assimilate (noncyanide 15N) first-order leaf loss rate were the only coefficients that significantly affected the model goodness of fit and were concurrently sensitive to data uncertainty in the parameter optimization. Saturation kinetics may be applicable for free cyanide uptake into plants, but not for ferrocyanide uptake, which may occur via preferential protein-mediated or inefficient transpiration stream uptake. Within the free cyanide system, the relative magnitudes of the saturation uptake parameters and the demonstration of an active role for plants in uptake relative to transpiration suggest the potential importance of preferential diffusion through the cell membranes as reported in the literature, rather than protein-mediated uptake. The fitted 13-parameter model matched the observed data well except for the predicted stem and leaf tissue assimilate concentrations, which were significantly underestimated, particularly in the free cyanide system. These low predicted values, combined with the slightly underestimated solution free cyanide removal, suggest that noncyanide 15N redistribution in phloem should be considered.
应用一种植物吸收模型来描述水培柳树（Salix eriocephala var. Michaux）中游离氰化物和亚铁氰化物的运输及归宿。该模型应用于实验数据，以确定最佳拟合参数值、其相关不确定性以及它们对田间规模植物修复应用的相对重要性。使用观测对数浓度的最小二乘法优化得到的拟合模型结果表明，叶组织中游离氰化物的挥发和游离氰化物在细胞壁上的吸附可忽略不计。游离氰化物的最大吸收速率和同化物（非氰化物15N）的一级叶片损失率是仅有的对模型拟合优度有显著影响且在参数优化中对数据不确定性同时敏感的系数。饱和动力学可能适用于游离氰化物进入植物的吸收过程，但不适用于亚铁氰化物的吸收，亚铁氰化物的吸收可能通过优先的蛋白质介导或低效的蒸腾流吸收发生。在游离氰化物系统中，饱和吸收参数的相对大小以及植物在吸收相对于蒸腾过程中所起的积极作用表明，如文献报道的那样，通过细胞膜的优先扩散而非蛋白质介导的吸收具有潜在重要性。除了预测的茎和叶组织同化物浓度被显著低估，尤其是在游离氰化物系统中，拟合的13参数模型与观测数据匹配良好。这些低预测值，再加上溶液中游离氰化物去除量略有低估，表明应考虑韧皮部中非氰化物15N的重新分布。
