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禾谷胞囊线虫(Heterodera avenae)是中国小麦生产的重要病原,造成小麦重大产量和经济损失。于2011—2012小麦生长季研究了北京地区禾谷胞囊线虫2龄幼虫的田间种群动态及侵染致病特征。结果表明:在小麦整个生长季内有2个2龄幼虫的孵化高峰。第1个小高峰出现在11月下旬,每100 m L土壤中最多可检测到105条2龄幼虫。而主要的孵化高峰出现在翌年春季的3月下旬—4月上旬,每100 m L土壤中最高可检测到295条2龄幼虫。秋季孵化的2龄幼虫能够侵染小麦并安全越冬,但春季孵化的2龄幼虫侵染更为严重,4月中旬平均每株小麦根系内可检测到230条幼虫。尽管禾谷胞囊线虫在1个生长季内可以侵染2次,但却只能发育形成1代成虫,至5月中旬平均每株小麦根系上雌虫数量可达287头。为了明确秋季侵染小麦的2龄幼虫来源,通过体外和体内试验检测了当季新形成胞囊的孵化和侵染潜力。结果表明:在4℃条件下保存100 d的胞囊相比保存50 d的胞囊能孵化出更多的2龄幼虫(P<0.05),而在室温保存50和100 d的胞囊均不能孵化出2龄幼虫。此外,经过4℃预处理的胞囊在小麦越冬期即可孵化2龄幼虫并造成侵染,而室温保存的胞囊不具有侵染能力。说明了低温诱导对于禾谷胞囊线虫北京种群的孵化是必要的,而秋季小麦根系侵染可能是残留在土壤中2年以上的胞囊所致。本研究结果将有助于加深对禾谷胞囊线虫生物学和生态学的认识。
Heterodera avenae is an important pathogen of wheat production in China, resulting in significant yield and economic loss of wheat. In the 2011-2012 wheat growing season, the population dynamics and pathogenic characteristics of 2nd instar larvae of cereal cyst nematode in Beijing were studied. The results showed that there were two hatching peaks of two 2nd instar larvae throughout the growing season. The first small peak occurred in late November with up to 105 second-instar larvae per 100 m L of soil. The main incubation peak appeared in late March to early April, with 295 second instar larvae per 100 m L of soils. The 2nd instar larvae hatched in autumn were able to infect wheat and live overwinter. However, 2nd instar larvae hatched in spring were more severely infected. In mid April, an average of 230 larvae could be detected in each root system. Although the H. cerealis can infect 2 times in one growth season, it can only develop into a generation of adult worms, and the average number of females per root of wheat reached 287 in mid-May. In order to clarify the source of 2nd instar larvae that invaded wheat in autumn, the incubation and infectivity potential of newly formed cysts during the season was examined by in vitro and in vivo tests. The results showed that more second-instar larvae hatched (P <0.05) than those preserved for 50 days at 40 ℃, while those preserved at room temperature for 50 and 100 days did not Hatching 2nd instar larvae. In addition, the pre-treated cysts at 4 ° C hatched 2nd-instar larvae and infested during winter, while non-invasive cysts at room temperature did not. It is indicated that the induction of low temperature is necessary for the hatching of the population of Heterodera glycines in Beijing, but the autumn wheat root infection may be caused by the cysts remaining in the soil for more than two years. The results of this study will help deepen the understanding of the cyst nematode biology and ecology.