Effects of Scarification and Water Soaking Treatment on Germination of Hard-Seeded Legumes

The crops showing hard seed character have high seed viability after seed storage for long period. The low germination rate due to hard seed coat, however, cause a problem of low seedling establishment in field condition. Three legumes used in the experiment, lablab bean (Dolichos lablab L.), asparagus bean (Vigna sesquipedalis L. Fruwirth), and soybean (Glycine max L. Merr.), showed low germination rate (26, 17, and 5%, respectively) due to thick and hard seed coat. In this study artificial treatment for breaking dormancy was tested in hard seeds. The effect of proper treatment was various depending on species. The germination rate of lablab bean was highly improved up to 94% by soaking into water for 24 hours. In the case of asparagus bean, the rate was increased up to 90% by soaking for eight hours near boiling water until it cools. The germination rate of small hard seed soybean was increase to 96% by soaking into concentrated sulfuric acid for 10 minutes. Ultrastructural change revealed by scanning electron microscope (SEM) reflects that the structure of micropyle was changed and water uptake was facilitated with all treatments tested in the experiment. Especially, sulfuric acid treatment resulted in the degradation of micropylar tissue. These results demonstrate that the artificial treatment including sulfuric acid and (hot) water soaking treatment for promoting water uptake can be applied to improve seed germination in legume seed with thick and hard seed coat.

두과 작물의 경실종자 발아촉진에 대한 종피연화처리의 효과

우리나라 재래 수집종인 제비콩, 갓끈동부와 쥐눈이콩은 종피가 매우 두껍고 딱딱하여 물 흡수가 어려워 발아율이 각각 26%, 17%와 5%에 불가하다. 이들 종자는 저장성에서 그 가치가 높이 평가되지만, 포장에 파종할 때 발아율이 낮아 문제가 되고 있다. 본 연구에서는 이들 종자의 발아율을 향상시키기 위하여 몇 가지 종피약화 처리를 실시하여 가장 효과적인 방법을 도출하였다. 종피약화 처리방법 중 가장 정상묘율이 높은 것은 제비콩은 tap water ($20^{\circ}C$)에서 24시간 침지 했을 때 85%이였으며, 갓끈동부는 hot water에서 8시간 침지했을 때 45%이였다. 그러나 소립이고 경도가 높은 쥐눈이콩은 진한 sulfuric acid에 10분간 침지 했을 때 72%의 정상묘율을 보였다.