Paschke Mark W, Valdecantos Alejandro, Redente Edward F
Department of Forest, Rangeland and Watershed Stewardship, Colorado State University, Fort Collins, CO 80523-1472, USA.
Environ Pollut. 2005 May;135(2):313-22. doi: 10.1016/j.envpol.2004.08.006.
Manganese toxicity thresholds for restoration plants have not been established. As a result, ecological risk assessments rely on toxicity thresholds for agronomic species, which may differ from those of restoration species. Our objective was to provide Mn toxicity thresholds for grasses commonly used in restoration. We used a greenhouse screening study where seedlings of redtop, slender wheatgrass, tufted hairgrass, big bluegrass, basin wildrye, and common wheat were grown in sand culture and exposed to increasing concentrations of Mn. The LC50, EC50-plant, EC50-shoot, EC50-root, PT50-shoot, and the PT50-root were then determined. Phytotoxicity thresholds and effective concentrations for the restoration species were generally higher than values reported for agronomic species. Our estimates of PT50-shoot for the five restoration grasses range from 41,528 to 120,082 mg Mn kg(-1). Measures of EC50-plant for these restoration grasses ranged from 877 to >6,000 mg Mn l(-1). These thresholds might be more useful for risk assessors than those based on crop plants that are widely used.
恢复植物的锰毒性阈值尚未确定。因此，生态风险评估依赖于农艺物种的毒性阈值，而这些阈值可能与恢复物种的不同。我们的目标是提供恢复中常用草类的锰毒性阈值。我们进行了一项温室筛选研究，将红顶草、细茎冰草、丛生毛草、大蓝草、盆地野麦和普通小麦的幼苗种植在砂培中，并使其暴露于浓度不断增加的锰环境中。然后测定了半数致死浓度（LC50）、植物半数效应浓度（EC50-plant）、地上部分半数效应浓度（EC50-shoot）、根部半数效应浓度（EC50-root）、地上部分半数毒性浓度（PT50-shoot）和根部半数毒性浓度（PT50-root）。恢复物种的植物毒性阈值和有效浓度通常高于报道的农艺物种的值。我们对五种恢复草类地上部分半数毒性浓度（PT50-shoot）的估计范围为41,528至120,082毫克锰/千克（-1）。这些恢复草类的植物半数效应浓度（EC50-plant）测量值范围为877至>6,000毫克锰/升（-1）。这些阈值可能比基于广泛使用的作物植物的阈值对风险评估人员更有用。
