Infection characteristic and life cycle of Meloidogyne graminicola in roots of rice variety Shanyou 63 were investigated by using artificial inoculations with sodium hypochlorite -acid fuschin staining method. The second juvenile invaded root within 4-6 hours following inoculation under crowed conditions of inoculum at 26 ℃ while their number of larvae increased the most in the roots during 24 ~48 h after inoculation, The second juveniles entered at meristem zone or elongation zone of roots, then migrated intercellularly in the cortical cells down towards to meristem region closly behind the root cap, lining up parallel to the long axis of the root. They began to penetrated into vascular bundles and fed until procambium in the meristem region gave rise to the well-developed vascular bundles. The second juveniles which lied from the meristem zone to the elongation zone of same root showed a steady increadse in the dimensions. The developmental levels of second juveniles may closely related to the time when the second juveniles become sedentary and penetrate into vascular bundles for feeding. Egg masses produced by matured females were entirely embedded in the cortex of root. After hatching inside the root, secondary infections of the second juveniles may take place by moving to developing lateral root or moving to meristem region closly behind the root cap of new root, and also fed until procambium gave rise to the well-developed vascular bundles. The shortest life cycle was completed in 22 days at 26 ℃, or in 18 days at an ambient temperatures of 26-37 ℃.%在人工接种情况下,利用次氯酸钠-酸性品红染色方法,研究拟禾本科根结线虫对汕优63杂交稻幼苗根系的侵染特性及其生活史.结果表明:在26℃大量群体接种情况下,2龄线虫在接种后4～6 h内侵入根系,主要侵入时间为接种后24～48 h:2龄幼虫侵入部位为根尖分生区或伸长区,侵入后虫体迁移方向与根纵中轴平行,在皮层薄壁细胞间迁移,最终聚集于根冠最内侧的分生区,直待分生区原形成层发育成维管束后,2龄幼虫才侵入维管束内取食:根冠内侧分生区至伸长区的2龄幼虫呈侵染态线状至长颈瓶状逐渐发育膨大过程,其发育快慢可能与2龄幼虫开始定殖并侵入维管来取食时间先后有紧密关系:2龄幼虫可直接在根内孵化,并迁移至发育中的侧根,或迁移到新根根冠内侧分生区处,待分生区原形成层发育成维管束后进行再侵染；拟禾科根结线虫最短生活史在26℃下为22 d,在26～37℃环境温度下为18 d,其侵染具有群体优势特性.
展开▼
