土壤湿度对大豆孢囊线虫侵染和繁殖的影响

为探讨土壤湿度对大豆孢囊线虫(Heterodera glycines,SCN)侵染和繁殖的影响,采用定量接种和钵栽试验方法,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(重量含水量MCW 2%~5%)、中湿度(MCW 10%~18%)和高湿度(MCW 20%~28%)状况下SCN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,低和高湿度处理下,SCN 2龄幼虫根系侵入量、3龄和4龄幼虫根内发育数量均较少.中湿度处理的SCN繁殖系数(Rf)为1.5,而低和高湿度处理的分别为0.7和0.4,比高湿度处理的分别减少了53%和83%.可见,土壤湿度过低和过高均不利于SCN的侵染,并明显抑制SCN的繁殖.

Effects of Soil Moisture on the Infection and Reproduction of Soybean Cyst Nematode

In order to explore the effects of soil moisture on the infection and reproduction of soybean cyst nematode (Heterodera glycines, SCN), the quantitative inoculation and pot experiment were conducted, and the population densities and dynamics of the different SCN developmental stages under three soil moisture treatments, the low one with the moisture content by weight (MCW) of 2%~5%, the middle one with the MCW of 10%~18% and the high one with the MCW of 20%~28%, were ascertained through the periodical sampling and the microscopic examination of the juveniles, white females and newly-formed cysts extracted from soil and the juveniles stained in soybean root.The results showed that the amounts of 2nd stage juveniles penetrated into root, 3rd and 4th stage juveniles developed in root, were less under the low and high moisture treatments than those under the middle moisture treatment, respectively.The reproduction factor (Rf) of SCN was 1.5 under the middle moisture treatment, but Rfs were 0.7 and 0.4, decreased by 53% and 83% under the low and high moisture treatments, respectively.It could be concluded that both too low soil moisture and excessive soil moisture were unfavourable for the infection of SCN, and obviously inhibited the reproduction of SCN.