水稻小穗头上的线虫形态特征鉴定

 对水稻生产上较大面积发现的“小穗头”现象，即稻穗长度缩短，籽粒明显减少, 米粒小且米色黑褐，部分籽粒为秕粒，剑叶形态正常，无干尖现象的成因进行了探讨。从水稻品种武育粳3号“小穗头”谷粒中分离到一种滑刃属线虫，百粒线虫数达2014条，单个谷粒带虫量最多可达74条，病穗中谷粒带虫率为92%。经外部形态和内部结构观察表明，虫体侧区具4条侧线，尾尖突为星状，具3~4刺突；雌虫后阴子宫囊短于肛阴距1/2，内无精子，卵母细胞多行排列，为2~4排；雄虫交合刺有一中等发育的缘突。虫体测量数据与Fortuner(1970)所测水稻干尖线虫的原始数据基本相符。因此，将该线虫鉴定为水稻干尖线虫Aphelenchoides besseyi Christie, 1942贝西滑刃线虫。

Description of Aphelenchoides besseyi from Abnormal Rice with Small Grains and Erect Panicles in China

The abnormal rice with small grains and erect panicles were found on a large scale in Jiangsu, China, which showed that the length of rice panicle was shortened and number of grains was decreased in comparison with normal rice, and grains were small and black-brown, moreover, some of them were unfilled, while flag leaf was normal. A kind of nematode of Aphelenchoides was isolated from the rice variety Wuyujing 3 with small grains and erect panicles. There were 2014 nematodes in one hundred grains infected, and up to 74 in a single grain, 92 percent of the grains tested had nematodes in the infested panicles. The diagnosis characters of nematode included that lateral fields was about one-fourth as wide as body, with four incisures. The terminus bore a mucro of diverse shape with 3-4 pointed processes. The female post-vulval uterine sac extends less than 50% of distance from vulva to anus, no sperm in it. Oocytes usually arranged in 2-4 rows. The male spicules has a middle rostrum. Morphological character and measurements showed that it might be conspecific with Aphelenchoides besseyi Christie, 1942.