Sensitivities of Urochloa decumbens Plants to Glufosinate

ABSTRACT: This study aimed to assess the response of Urochloa decumbens plants to different doses of glufosinate ammonium, and the sensitivity of plant population to the herbicide. Two studies were conducted, both in greenhouse and repeated at different times. In the dose-response analysis, two experiments were conducted using seven doses of the glufosinate ammonium (0, 50, 100, 200, 400, 800, and 1,600 g a.i. ha-1) with four replications each. In the analysis of sensitivity levels of U. decumbens to herbicide, 44 plants were sprayed with a dose of 200 g a.i. ha-1 of the herbicide. Tissue ammonium content was determined, and injury percentage was visually assessed. Experiment data were converted to mg of ammonium per kg-1 of fresh mass and submitted to analysis of variance, and treatment means were compared by t test (p?0.10). Control of Urochloa decumbens plants by glufosinate might be associated with plant tissue ammonia content, which increased as a function of herbicide application, but not linearly as a function of dose rate. Variability existed in the ammonium content among the individuals of the population of U. decumbens.摘要：本研究旨在评估俯仰臂形草（Urochloa decumbens）植株对不同剂量草铵膦的响应，以及该植物种群对该除草剂的敏感性。本研究共开展两项试验，均于温室内开展并在不同时间重复进行。在剂量响应分析中，设置7个草铵膦施用剂量（0、50、100、200、400、800及1600 g a.i. ha⁻¹），每个剂量设置4次重复。在针对U. decumbens种群对除草剂的敏感性水平分析中，选取44株植株喷施200 g a.i. ha⁻¹的草铵膦。测定植株组织内的铵含量，并通过目视法评估植株受害率。试验数据被转换为每千克鲜质量对应的铵质量（mg·kg⁻¹鲜质量），随后进行方差分析，采用t检验比较处理均值（p≤0.10）。研究表明，草铵膦对俯仰臂形草的防除效果可能与植株组织内的铵含量相关，该含量随除草剂施用而升高，但并非随剂量呈线性变化。此外，该种群内不同植株个体间的铵含量存在变异。