为明确土壤湿度对烟草孢囊线虫（Heterodera glycines，HGT）侵染的影响，采用定量接种和杯栽试验方法，通过定期取样、土壤中线虫分离和根组织中线虫染色后镜检，测定了3种土壤湿度—低湿度（体积含水量MVP 3%～9%）、中湿度（MVP 15%～25%）和高湿度（MVP 30%～40%）状况下HGT不同虫态群体密度及其动态变化。结果表明，与中湿度处理相比，低湿度处理下，HGT 2龄幼虫在土壤中的孵化和对根系的侵入均受到抑制，根组织中3龄和4龄幼虫发育量明显减少且发育进程延迟；高湿度处理下，HGT 2龄幼虫对烟草根系的侵入加快，根组织中3龄和4龄幼虫的发育提前。低、中和高湿度处理下HGT的繁殖系数（Rf）分别为0.7、1.0和0.4。可见，土壤湿度过低和过高均不利于HGT正常侵染，湿度过高对HGT繁殖的抑制作用尤其明显。%The purpose of this study was to investigate the effects of soil moisture on the infection of tobacco-infecting cyst nematode (Heterodera glycines, HGT). In the study, quantitative inoculation and cup experiment were conducted, and population densities and dynamics of different HGT developmental stages under three soil moisture treatments, the low one with the moisture volume percentage (MVP) of 3%-9%, the middle one with the MVP of 15%-25%and the high one with the MVP of 30%-40%, were ascertained through periodical sampling and microscopic examination of the juveniles, white females and newly-formed cysts extracted from soil and the juveniles stained in tobacco roots. The results showed that the emergence in soil and penetration to root of HGT 2nd stage juveniles were both inhibited, and the developmental quantities and processes of the 3rd and 4th stage juveniles were obviously decreased and delayed under the low moisture treatment as compared with the middle one. The penetration to root of the 2nd stage juveniles were speeded up and the development of the 3rd and 4th stage juveniles occurred ahead of time under the high moisture treatment as compared with the middle one. The reproduction factors (Rf) of HGT were 0.7, 1.0 and 0.4 under the low, middle and high moisture treatments, respectively. It could be concluded that both too low and excessive soil moistures were unfavorable for the normal infection of HGT, and excessive moisture inhibited the reproduction of HGT more obviously.
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