【正文】 sessing the power of killing or preventing the growth of fungi. ?殺菌劑（ fungicide）：殺菌、抑菌、提高抗病力，所有這種能達(dá)到防治植物病害的農(nóng)藥都是殺菌劑。 ?在離體下無殺菌毒性，在活體內(nèi)通過削弱病原菌的致病能力或者提高寄主抗病能力來達(dá)到防治病害的作用機理也被稱為間接作用機理 (indirect mode of action) 。1,3 Glucanase（葡聚糖酶） ? Systemic accumulation of antimicrobial pounds called phytoalexins（植物抗毒素） . 53 Chitinases ? Chitin is the major ponent of all fungal cell walls except for the Oomycetes ? Chitinases break down fungal cell walls ? Chitinases can break down insect exoskeletons ? Activity is greatly enhanced by Glucanase 54 223。 ?第二代殺菌劑（ anic chemicals） ?傳統(tǒng)保護劑 (conventional protectants) ?植物藥害 (phytotoxicity) ； ?第三代殺菌劑：內(nèi)吸性殺菌劑（ systemic fungicide ） ?第四代殺菌劑：三環(huán)唑等較早使用的無殺菌毒性化合物。 10 Classification according to action ?(b) postinfection curative fungicides which kill (inhibit) the developing mycelium in the plant epidermis. ?(c) Postsymptomatic eradication fungicides which perate and kill the mycelium and new spores. 11 Classification according to action ?保護型殺菌劑 protective fungicide ?鏟除性殺菌劑 eradication fungicide ?治療性殺菌劑 curative fungicide ?內(nèi)吸性殺菌劑 systemic fungicide 12 Toxicity of fungicide ?In general, fungicides are of low to moderate mammalian toxicology, although they are believed to have a higher overall incidence than other pesticides to cause developmental toxicology and oncogenesis. 13 Toxicity of fungicide ?It has, for example, been estimated that more than 80 per cent of all oncogenic risk from the use of pesticides es from a few fungicides. 14 Toxicity of fungicide ?Fungicides usually are responsible for only a small proportion of pesticiderelated deaths, and account for only about 5 per cent or less of human pesticide exposures reported to Poison Control Centers. 15 Toxicity of fungicide ?It has been noted that since fungi differ significantly in morphology and physiology from other forms of life, they may be successfully bated by pounds of low toxicity to other anisms, notably mammals. 16 ?Part II ?Mode of Action 17 殺菌劑毒理學(xué) ?殺菌作用 (fungitoxicity) ?抑菌作用 (fungistasis) ?內(nèi)吸性殺菌劑 (systemic fungicides, systemics) ?抗產(chǎn)孢劑 (antisporulants) 18 內(nèi)吸性殺菌劑（ systemic fungicide ） ?選擇性 (selectivity) ? (1) 靶標(biāo)位點 (target site)和作用位點(site of action) ? (2)靶標(biāo)受體 (receptor)對藥劑的親合力(affinity)的差異 ? (3)藥劑對原生質(zhì)膜滲透性 (permeability)的差異 ? (4)對殺菌劑的積累 (或排出 )、解毒(detoxify)作用的差異等 19 殺菌劑毒理學(xué) ?離體（ in vitro） 活體（ in vivo） ?無殺菌毒性化合物 (nonfungitoxic pounds) ? (1)干擾病原菌的致病機理，削弱病原菌的致病力或使病原菌不能侵入；三環(huán)唑(tricyclazole)為抗穿透劑(antiperant) ? (2)提高寄主植物的