대두근류균(大豆根瘤菌)의 질소고정(窒素固定)에 관(關)한 연구 -I. 대두(大豆) 근류균(根瘤菌)의 질소고정력(窒素固定力) 측정방법(測定方法) 및 질소고정량(窒素固定量)

Studies on Symbiotic Nitrogen Fixation in Soybean -I. Methods of Measurement and Amounts of Symbiotic N₂ Fixation in Soybean Root Nodules

대두(大豆) 근류(根瘤)로부터의 질소고정능(窒素固定能)을 아세치렌 환원법(還元法)($C_2H_2-C_2H_4$)으로 측정(測定)할 경우(境遇)의 실험방법) 및 대두(大豆) 생육기간중(生育期間中) 근류(根瘤)로부터 고정(固定)되는 질소량(窒素量)을 파악하고져 pot 및 실내실험으로 수행(遂行)하였든 바 다음과 같은 결과(結果)를 얻었다. 1. 아세치렌 환원법(還元法)으로 근류(根瘤)의 질소고정능(室素固定能)을 측정(測定)할 경우(境遇), 근류(根瘤)를 뿌리에 붙은 상태(狀態)로 측정(測定)하면 아세치렌 충전후(充塡後) 항온(恒溫) 2시간(時間)에 측정(測定)하는것이 이상적(理想的)이었으며, 근류(根瘤)를 분산(分離)시키면 측정치(測定値)의 경시적 변동이 컸다. 2. 대두(大豆) 파종후(播種後) 근류형성량(根瘤形成量)은 55일(日), 질소고정량(室素固定量)은 40일(日)까지 직선적(直線的)으로 증가되었으나 그 이후(以後)부터는 감소(減少)되는 경향(傾向)이었다. 3. pot에서 대두(大豆) 1작기(作期) 생육기간중(生育期間中) 근류(根瘤)에 의(依)한 질소고정량(窒素固定量)은 반당(11,100본위모(本立毛)) 약(約) 8.0kg/10a로 추정(推定)되었다.

A series of experiments were conducted on procedures of $N_2$ fixation measurements with soybean (Glycine max. L.) root nodules by acetylene reducing assay and estimation of amounts of $N_2$ fixed by soybean root nodules grown in the pot. The results are summarized as follows; 1. In case of nitrogen fixing activities were determined by means of acetylene reducing method, more appropriates results were obtained with direct determination of root nodules which was adhering from root under 2 hours after incubation, while more fluctuated data was obtained with root nodules determined under separated conditions. 2. The weight of soybean nodules was linearly increased from 17 days to 55 days after planting, whereas, the amounts of $N_2$ fixation from soybean nodules were Peaked at 38 days after planting, and declined thereafter. 3. When calculated upon the basis of the amounts of $N_2$ fixed as measured by acetylene reducing activities in single soybean plant, it was found that the average amount of symbiotic $N_2$ fixation falls in the range of 80 kg N per ha.