禾草類除草劑(graminicides)為一種萌後施用的選擇性除草劑，主要抑制禾本科雜草的生長， 依分子架構可分為兩類： 包括aryloxyphenoxypropionates 和cyclohexanediones，其作用為抑制脂肪酸合成路徑中第一個關鍵酵素乙醯輔酶A 羧化酵素(acetyl-coenzyme A carboxylase; ACCase)之活性，使植物無法合成脂肪酸，造成細胞膜構造受到破壞而導致植物死亡，此類除草劑亦可稱為ACCase 抑制型除草劑。植物細胞中的ACCase 可分為原核生物型(prokaryotic)及真核生物型(eukaryotic)兩種，於原核生物(prokaryote)的質體(plastids)中通常存在著多次單位(multisubunit)的ACCase 類型，屬於原核生物型ACCase；而真核生物(eukaryote)的細胞質(cytosol)中通常存在多功能型(multifunctional)的ACCase，屬於真核生物型ACCase。一般而言，禾草類除草劑會抑制質體中真核生物型ACCase 的活性，研究報告顯示禾本科植物質體中存在的MF ACCase 正是禾草類除草劑作用之目標位置，而MS ACCase 則對此類藥劑很不敏感。本篇報告主要探討禾草類除草劑所作用的目標酵素中兩類型ACCase 在不同植物物種中的分佈，以及在禾草類除草劑處理下抗性植物中ACCase 所扮演之角色。

Graminicides are postemergence herbicides selectively used in cereal crop fieldsfor the control of grass weeds. The action mechanism of this kind of herbicidesincluding aryloxyphenoxypropionates and cyclohexanediones is the inhibition ofacetyl-coenzyme A carboxylase (ACCase) activity, results in the blocking of fatty acidbiosynthesis and damage of cell membrane integrity. In general, there are two types ofACCase, i.e., prokaryotic and eukaryotic ACCase, in higher plants, the formercommonly exists in plastids and this protein complex consists of 4 different subunits(multisubunit ACCase), and the latter exists in cytosol in a single polypeptide form with4 corresponding subunit domains, also called multifunctional ACCase (MF ACCase). Ingerenal, the activity of eukaryotic ACCase in plastids of grass plants is susceptible toand inhibited by graminicides, whereas that of prokaryotic ACCase (MS ACCase) islittle affected. The distribution of both types of ACCase in higher plants, and the role ofACCase in the graminicide resistance are discussed.