Phytophtora cinnamomi引起之進口百合種球疫病

西元２０００年３月，一批自荷蘭進口之葵百合（Lilium oriental hybrid cv. Star Gazer）種球芽體發生嚴重腐敗，新芽基部與頂稍呈褐變腐敗狀；種植時，罹病百合植株莖部無法抽長即腐爛死亡。罹病組織經分離得到疫病菌 Phytophthora cinnamomi。以游走子或厚膜孢子懸浮液接種葵百合（cv. Star Gazer）種球之新芽，無論有無傷口，均可誘發病害，但有傷口時，發病較嚴重。接種種球苗產生之病徵與自然界發生者相同；但以菌絲塊接種時，不能造成病斑。另外，以游走子接種盆栽百合之頂芽和莖部時，發現本菌只為害幼嫩的頂芽。分離到的P. cinnamomi 三個菌株均為A1配對型。該菌在V–8培養基上之菌落白色平滑，無特殊花紋；菌絲生長溫度８－３２℃，最適２８－３２℃；在培養基上不產胞，但產生大量球形厚膜孢子（Chlamydospores），以及珊瑚狀菌絲膨脹體（coralloid hyphae swellings）。以礦物鹽液水洗處理後，可形成大量的胞囊（proliferated sporangia）。胞囊大小27 .5-67.5μm × 22.5-45.0μm，平均為48.6 × 34.7 μ m，胞囊長寬比1.06 –3.0，平均為1.58。P. cinnamomi 危害百合種球為苜度在台灣報導，推測可能因該菌之強腐生能力，殘存於介質中，隨百合種球入侵台灣，造成種球芽體腐敗。

關鍵字

百合；鱗莖；疫病；厚膜孢子；游走孢子；接種方法

並列摘要

In March 2000, most of the lily bulbs (Lilium oriental hybrid cv. Star Gazer) in a cargo from the Netherlands were found to be rotten. Shoots and basal portions of the affected bulbs showed brown discoloration and deterioration. When these blight bulbs were planted in the medium, stem shoots did not grow and the bulbs eventually died and rotten. Phytophthora cinnamomi was isolated from all the diseased tissues obtained from the affected bulbs. Both zoospore and chlamydospore suspensions, but not mycelia, of the isolated organism caused brown rot to the young shoots of lily bulbs (cv. Star Gazer) in the pathogenicity tests. The disease symptoms induced by the fungus via artificial inoculation were similar to those occurring in nature. Phytophthora cinnamomi was reisolated from the diseased tissues of inoculated plants. Wounding is not required for successful infection of lily bulbs by the fungus, but the disease was more severe when bulbs were Wounded, Zoospores of the pathogen could only infect very young tissues of lily plants such as buds and shoots. They were not able to infect the old stem tissues. To our best knowledge, this is a previously unreported new disease. All three isolates of P. cinnamomi obtained from lily bulbs were of the typical type and belonged to A 1 mating type. Colonies of the fungus on V –8 gar were white and smooth. The fungus failed to grow at 36℃ but were still able to grow at 8℃. Chlamydospores and coralloid hyphae swellings but not sporangia were produced on solid medium. However, abundant sporangia were produced when myceial mates were washed with a mineral solution for 3 times and incubated under light at 24°C. Sporangia were subspherical or lemon-shaped, non-deciduous and non-papillate. New sporangia were found successively Within or beyond empty sporangia by renewed growth of sporangiophore through the base of the original sporangium. Sporangia measured 27 .5-67.5μm × 22.5-45.0μm with an average of 48.6 × 34.7 μ m. The length/width (L/B) of sporangia ranged from 1.06 to 3.0 with a mean as 1.58.

並列關鍵字

Lily ； Phytophthora cinnanzomi ； zoospore ； chlamydospore ； inoculation ； first report

國際替代計量

Phytophtora cinnamomi引起之進口百合種球疫病

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