椰子平臍蠕孢葉斑病病原菌鑒定及生物學特性測定

摘 要 2012年10月，在海南省文昌市的椰子苗圃中，發(fā)現(xiàn)了一種新的葉斑病。顯微觀察表明，病原菌分生孢子稍彎曲，淺褐色，紡錘狀或梭狀，具有5～9個假隔膜、分生孢子梗多單生，直立或稍彎曲，表明其為平臍蠕孢屬（Bipolari. sp）。ITS序列分析表明其和4株狗尾草平臍蠕孢的序列同源性（HE792936.1，JX462256，GUO73108.1，F(xiàn)J606786.1）的同源性為99%。生物學特性研究結(jié)果表明：該菌菌絲適宜生長溫度為20～30 ℃，菌絲生長和孢子最適萌發(fā)溫度分別是25 ℃和30 ℃；最適pH值為4～11；玉米粉培養(yǎng)基（CAM）及馬鈴薯葡萄糖瓊脂培養(yǎng)基（PDA）最適合菌絲生長，最佳碳源為蔗糖，甘油不適合菌絲生長；最佳氮源為蛋白胨，其次是磷酸氫二銨；完全光照有利于菌絲生長。菌絲及分生孢子的致死溫度和時間分別是56 ℃，15 min。

關鍵詞 椰子；平臍蠕孢；生物學特性

中圖分類號 S435. 61 文獻標識碼 A

Abstract In October 2012， a new leaf spot disease was observed on coconut seedlings in Wenchang， Hainan province. Based on microscopic observation， the conidiophores were slightly flexuous or straight， produced curved， spindle-shaped or fusiform， septate conidia with 5 to 9 pseuedo-septa. Thus， the pathogen belong to Bipolari. sp. Furthermore， the result of ITS sequence analysis revealed 99% sequence similarity with B. setariae. The results of biological characteristics showed that CAM and PDA medium were the best for the mycelial growth of pathogen. Temperature ranged from 20 to 30 ℃ were optimum for its mycelia growth， and conidia germinated best on 30 ℃. pH ranged from 4 to 11 was optimum for its mycelia growth. The mycelia grew best on media with sucrose as C source. Peptone nitrate and was the best nitrogen sources for mycelial growth and the（NH4）2HPO4 nitrate was the second. Continuous light was the best for mycelial growth. The lethal temperature was 56 ℃， 15 minutes for hypha growth and conidiospore.

Key words Cocos nucifera L.； Bipolaris.sp； Biological characteristics

doi 10.3969/j.issn.1000-2561.2015.03.023

椰子（Cocos nucifera L.）屬于棕櫚科椰子屬，是熱帶地區(qū)主要的木本油料作物之一，綜合利用經(jīng)濟效益高，故享有“寶樹”之稱， 具有極其重要的觀賞價值[1]。在海南、廣西、廣東、云南、四川、福建及臺灣等?。▍^(qū)）均有種植，其中主要集中在海南省，種植面積已達到約14萬hm2[2]。隨著海南國際旅游島建設步伐的加快，椰子的需求量日益增加、供不應求，其經(jīng)濟價值也逐年提升，致使椰子種植面積不斷擴大，但隨之而來的椰子樹的病害也日趨嚴重，制約了椰子產(chǎn)業(yè)化的發(fā)展。

2012年10月，筆者在海南省文昌市椰子研究所椰子種植苗圃發(fā)現(xiàn)了一種新的葉斑病，該病主要為害椰子葉，嚴重影響長勢并降低觀賞價值。該病主要危害2～6齡椰子幼苗，嚴重時病斑擴大至葉尖，整片葉子枯萎死亡?！?br>