저산소 조건이 보리 유묘의 탄수화물대사에 미치는 영향

Effect of Hypoxia on Carbohydrate Metabolism in Barley Seedlings

본 연구에서는 보리 습해의 원인인 과습에 의한 근권의 산소부족이 보리의 뿌리와 지상부의 amylase 및 sucrose synthase 활성에 미치는 영향을 배양액의 용존산소를 1~2 ppm의 혐기조건으로 1-7일간 처리한 3엽기 보리 유묘를 이용하여 조사하였다. 해당과정의 재료인 glucose의 공급에 관여하는 효소 중에서 전분을 분해하는 α-amylase의 활성은 혐기조건에서증가하나 자당을 분해하는 sucrose synthase활성은 혐기조건에서도 호기적 상태의 수준을 유지하였다. 이러한 결과는 에너지 획득과정에서의 α-amylase의 역할이 호기조건에서보다 혐기조건에서 상대적으로 증대하는 것을 의미하는 것으로 사료된다.

Barley plants growing in the wet paddy field easily encounter suboptimal oxygen concentration in the rhizosphere that causes molecular oxygen deficiency in root cells. The capacity of root cells to utilize energy sources is known to be positively related to resistance to hypoxia stress. This study was conducted to investigate effects of hypoxia on enzymes involved in the starch and sucrose metabolism. Barley seedlings at the third leaf stage were subjected to hypoxia (1 ppm dissolved oxygen) by purging the culture solution with nitrogen gas for up to seven days. The protein content was slightly decreased by hypoxia for 7 days. α-Amylase activities increased significantly in the root but not in the shoot after 3 to 7 days of hypoxia. β-Amylase activities were not affected significantly in both tissues. Additionally, sucrose synthase activities were affected little in both tissues by 7 days of hypoxia. The results indicate that root cells activate breakdown of polysaccharide reserves in response to an acute hypoxia to supply energy sources for fermentative glycolysis and cell wall fortification.