Effect of Herbicides on the Survival of Soybean Nodule Bacteria(Rhizobium japonicum) in vitro.

제초제의 처리가 콩 근류균의 생존율에 미치는 영향

Since most chemicals effect to the non-target organisms, present study was conducted to determine the effects of some herbicides to soybean nodule bacteria(Rhizobium japonicum) in vitro. Selective upland herbicides Alachlor, Linuron, Simazine and nonselective Paraquat were medicated to the YEMA media and survival rate of the bacteria in the medium was measured a week after incubation. Survival of soybean nodule bacteria in the media medicated with recommended concentration 400 ppm of Alachlor and Linuron were decreased significantly by 27.4 ％ and 57.8 ％, respectively. While little effect was observed in Simazine, a marked reduction of survival was observed in 200 ppm of Paraquat. Effects of Alachlor was different with isolates of the nodule bacteria. Isolate I -122 was relatively resistant and I -145 was more sensitive. than other isolates tested. Intermediate K-5 was the most resistant at the recommended dose and the survival dose was drastically reduced with increment of concentration. Nodule formation of the soybean plants was different with the varieties and isolates. The most nodulation was observed in the resistant isolates I -122 and K-S, for which the nodulation might be related with the resistance to the environmental stress factors.

콩포장에 사용하는 제초제가 근류균의 생존률에 미치는 영향을 구명하기 위하여 제초제 Alachlor, Linuron, Simazine 및 Paraquat를 농도별로 YEMA 배지에 혼합하여 근류균을 접종, 배양하여 생존률을 조사하였다. 1. 콩근류균은 Alachlor와 Linuron의 사용권장 농도인 400ppm 처리에서도 각각 27.4％와 57.8％의 생존률을 보여 유의한 근류균의 감소를 보였다. 2. Simazine은 공시제포제중에서 가장 영향이 적었으며 Paraquat는 200ppm에서도 현저한 생존균수의 감소를 보였다. 3. Alachlor에 대한 근류균의 감수성은 균주에 따라 차이가 있었으며 I-122 균주가 가장 낮은 감수성을, I-145가 가장 높은 감수성을 보였고 중도 저항성인 K-5 균주는 사용권장농도에서는 높은 저항성을 보였으나 농도가 증가함에 따라 급격히 감소하였다. 4. 콩품종의 근류형성력은 균주, 품종에 따라 차이가 있었으며 Alachlor에 저항성인 균주 I-122, K-5 가 높은 근류형성력을 보여 근류형성력은 환경적응력과 밀접한 관계가 있는 것으로 보였다.