旱稻孢囊线虫生活史及侵染特性

Life Cycle and Infection Characteristics of Rice Cyst Nematode,Heterodera elachista Ohshima in Rice

以2龄幼虫人工接种水稻幼苗和田间定点调查的方法,研究了旱稻孢囊线虫的生活史和侵染特性。结果表明,在30℃下接种后24h内,2龄幼虫大多聚集在根尖分生区或伸长区,接种后24h可侵入根系,侵入后虫体在中柱建立取食点;接种后6d,2龄幼虫发育成白雌虫,8d发育成雄虫,12d雌虫从阴门处产生胶状物质,雌虫的一部分卵产于胶质卵囊中。接种后18d,胶质卵囊中的2龄幼虫开始孵化。在30℃下,旱稻孢囊线虫从卵到卵的最短生活周期为22d;从接种到2龄幼虫从胶质卵囊中孵出,最短生活周期为18d。20℃下线虫发育缓慢。较高温度如28℃～35℃有利于2龄幼虫的侵染和发育。淹水条件不利于2龄幼虫的侵染,但对孢囊的发育无显著影响。

I.ife cycle and infection characteristics of Heterodera elachista in rice were investigated by artificial inoculations with second instar juveniles in laboratory and investigation in rice field. The second-instar juveniles were attracted nearby the meristem zone or elongation zone of rice root tips within 24 h, invaded and established feeding sites in the central cylinder of roots within 24 h at 30°C. After penetration, the juveniles developed into white females within six days and males within eight days. The gelatinous matrixes were secreted by the females from vulva within 12 days. Parts of eggs were released into the egg sac and parts of eggs were retained within the body of the brown cyst. The second-instar juveniles were emerged from egg mass within 18 days. The development of nematode were very slow below 20°C. The shortest life cycle at 30°C from the infective juvenile to the emergence of second instar juvenile is 18 days long while from egg to egg stage is 22 days. Relatively high temperatures（28-35 °C ） were favored to the invasion and development of H. elachista, while waterlogging reduced the rates of invasion and had no influence on the development of H. elachista.