• 作者： 陳?紀
• 作者服務機構： 國立中興大學植病系
• 中文摘要： 本研究室利用電子顯微鏡檢查水稻黃萎病，甘蔗白葉病，狗牙根白葉病，四生臂形草白葉病，柑枯黃龍病，甘藷簇葉病，大豆簇葉病，絲瓜簇葉病及蕃茄簇葉病等叢生萎黃病類之病組織之結果，均於其韌皮部（主為篩管）內發現多數大小不一而多形性之類似菌質體。此種菌體外圍具有單位膜，但無細胞壁，內部充滿核醣體顆粒及類似DNA之網狀絲。核醣體顆粒一般多位於菌體之周邊，而網狀絲則位於菌體中央較空虛之部位。 在所有的病例，大小不一之類似菌質體混生於同一細胞內，由此可推測此種類似菌質體乃由小型之菌體漸次變為大型者。又有些觀察顯示成熟之菌體，以芽殖或裂殖方式增殖之情形。於水稻黃萎病之場合，類似菌質體累積於篩板兩側，並有菌體變細而通過篩孔之情形，顯示此類菌質體乃經由篩孔而傳導至植物體各部位。 以四環素處理水稻黃萎病病株，使病徵減輕或消失時，組織內之類似菌質體顯著減少，但經一段時日，病徵再度出現時，菌體又恢復生長與繁殖，故四環素只能暫詩抑制類似菌質體之生長而不能將其完全消滅。
• 英文摘要： Electron microscopic examination fromyoung leaves infected with rice yellow dwarf,sugarcane white leaf, Cynodon dactylon whiteleaf, Brachiaria distachya white leaf, citruslikubin, sweet potato witches' broom, soybeanwitches' broom, loofah witches' broom andtomato witches' broom revealed the presence ofpleomorphic bodies which resembled Mycoplasmaspecies: The Mycoplasma-like organisms (MLO)were fround in various size and varying con-centration in sieve elements of vascular tissue.These bodies were possesed. of a three-layeredunit membrane and were filled with ribosomegranules and DNA-like net-strands in the cyto-plasm. Occasionally, budding-like protrusion fromthe large bodies and constriction at themiddle of the large bodies were observed whichwere suggestive of multiplication of new bodies.The diversity in size of the bodies found sim-ultaneously in one cell might represent theirdeveloping stages. In rice yellow dwarf MLOwere found coucentrated along both sides ofsieve plates. Some were found extruding intothe sieve pores, indicating that cell to celldistribution of the organisms might take placethrough such pores. The number of MLO in diseased sieveelements decreased as the symptom disappearedby treatment with tetracycline-HCL. They couldgrow and reproduce again when symptoms re-appeared. Therefore, tetracycline treatment-depressed only the growth of MLO in diseasedplants but did not kill them completely.
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