白絹病菌菌核培養在含10m molal（0.06%w/w）之自然土表或暴露於含0.5％尿素之自然土中，則失去其活力，將其外表橫切面及內部組織經掃描電子顯微鏡及光學顯微鏡下觀察，得知其與未經處理之菌核共無明顯差異。但可發現在經處理過之菌核表面裂縫處有大量微生物聚集。暴露在0.5％尿素自然土中之菌核，可見有滲出物的產生，此滲出物經以anthrone及ninhydrin呈色反應，得知是醣類和氨基酸。經處理過之菌核平均每一個滲出之醣量為47.5ug約等於無處理者（15ug）之3.2倍，而滲出的氨基酸量為0.28 mM 約為無處理者（0.02mM）之14倍。
Study on the Etiologiy of Lost Viability of Sclerotium rolfsii in Urea-amended Soil
Fang, H. C.
The purpose of this experiment mainly was to discuss the selerotia of Sclerotium rolfsii that lost viability in urea-amended natural soil. As examined by both scanning electron microscopy (both surface view and cross section) was noted between untreated sclerotia and sclerotia which had been placed on 10 m molal (0.06% w/w) urea-amended natural soil or exposed to the atmosphere of 0.5% urea-amended natural soil. Only treated sclerotia showed abundant aggregate of microorganisms in surface cracks. Sclerotial leakage was detected in the sclerotia that had been exposed to the atmosphere of 0.5% urea-amended natural soil. The anthrone and ninhydrin tests indicated that the leakage contained carbohydrates and amino acids. The average leakage of carbohydrates and amino acids of one treated sclerotium were 47.5 µg and 0.28 mM, respectively. They were 3.2 and 14 times higher than the untreated ones (15µg, 0.22 mM).
Accepted for publication: October 9, 1991.