Koger Clifford H, Shaner Dale L, Krutz L Jason, Walker Timothy W, Buehring Nathan, Henry W Brien, Thomas Walter E, Wilcut John W
Crop Genetics and Production Research Unit, USDA-ARS, Stoneville, MS 38776, USA.
Pest Manag Sci. 2005 Dec;61(12):1161-7. doi: 10.1002/ps.1113.
Greenhouse and field studies were conducted to investigate response of two rice varieties, Priscilla and Cocodrie, to sub-lethal rates of glyphosate in terms of injury, shikimate accumulation and yield. In the greenhouse, more shikimate accumulated in Cocodrie than Priscilla at comparable glyphosate rates applied to plants at the three-leaf stage. In field studies, glyphosate was applied to both varieties when they were 74-cm tall and in the internode separation growth stage. Visual injury, plant height, and leaf-tissue samples for shikimate analysis were collected at 3, 7, 14, 21 and 28 days after treatment (DAT). Rice yield was also determined. Noticeable visual injury and height reduction to both varieties was observed as early as 7 and 3 DAT in Cocodrie and Priscilla, respectively. Shikimate levels in leaves began to increase in both varieties by 3 DAT in a dose-dependent manner and reached a peak between 7 and 14 DAT. Elevated shikimate levels were still detectable by 28 DAT. Similar levels of shikimate accumulated in both varieties at comparable glyphosate rates. However, glyphosate treatment at comparable rates reduced rice yields more in Cocodrie than in Priscilla. The highest rate of glyphosate reduced yield in Cocodrie by 92% whereas there was only a 60% yield reduction in Priscilla. Shikimate levels in glyphosate-treated rice were strongly correlated to yield reductions across both varieties and appeared to be a better predictor of yield reduction than was visual injury. Visual injury coupled with measured shikimate levels can be used collaboratively to identify glyphosate exposure and estimate subsequent rice yield reductions.
开展了温室和田间研究，以调查两个水稻品种（普莉西拉和科科德里）在受到亚致死剂量草甘膦影响时，在损伤、莽草酸积累和产量方面的反应。在温室中，当在三叶期对植株施用相当剂量的草甘膦时，科科德里积累的莽草酸比普莉西拉更多。在田间研究中，当两个品种长到74厘米高且处于节间分离生长阶段时，对它们施用草甘膦。在处理后3、7、14、21和28天（DAT）收集视觉损伤、株高以及用于莽草酸分析的叶片组织样本。同时测定了水稻产量。早在处理后7天和3天，分别在科科德里和普莉西拉中观察到两个品种明显的视觉损伤和株高降低。两个品种叶片中的莽草酸水平在处理后3天开始以剂量依赖的方式增加，并在7至14天达到峰值。到处理后28天，仍可检测到升高的莽草酸水平。在相当的草甘膦剂量下，两个品种积累的莽草酸水平相似。然而，相当剂量的草甘膦处理使科科德里的水稻产量比普莉西拉降低得更多。草甘膦最高剂量使科科德里的产量降低了92%，而普莉西拉仅降低了60%。草甘膦处理的水稻中的莽草酸水平与两个品种的产量降低密切相关，并且似乎比视觉损伤更能预测产量降低。视觉损伤与测得的莽草酸水平相结合，可以共同用于识别草甘膦暴露情况并估计随后水稻产量的降低。
