Among various environmental stresses, humid stress lacks mechanisms and biochemical understanding compared to drought, low temperature, and high salt stresses. The aim of this study was to investigate enzyme activity of field crops under humidity stress. Results of this study could be used as basic data for understanding humidity stress and early diagnosis. Growth and enzyme activities of sesame, perilla, red beans, sorghum, and beans as major field crops in Korea when flooded were investigated. It was confirmed that growths of both shoots and roots were retarded. In plants, anaerobic fermentation occurred due to flooding stress, which increased the activity of alcohol dehydrogenase (ADH) compared to the control group. Increases of reactive oxygen species (ROS) were also observed. All flooded plants showed increased peroxidase (POD) activity and lipid peroxidation. Their dyeing strength was darker than that of the control group, even in 3,3´-diaminobenzidine (DAB) staining. Since enzyme activity changes in plants appear relatively faster than changes in phenotype at the ground level, they could be used as biomarkers for early diagnosis of humidity stress in crops.

지구기후가 이산화탄소 배출 증가로 인해 급격하게 변화하고 있는 추세이고, 이러한 급격한 기후 변화는 농경지 염류직접, 농경지 침수, 고온 및 저온과 같은 농업 기상의 다양한 변화를 야기하고 있다. 여러 환경스트레스 중에서 농경지 침수는 경작지 내 과도한 수분 유입으로 인해 유도되게 된다. 특히 많은 과학자들은 탄소 배출 증가로 인한 기후변화로 인해 집중호우가 지금보다 더 자주 발생할 것으로 예상되고 있기 때문에 농경지의 침수로 인한 농작물의 피해는 점점 더 증가할 것으로 예상하고 있다. 침수로 인한 스트레스에 대한 식물의 취약성 및 저항성 메커니즘에는 중요한 변화가 있다. 그러므로 이런 침수스트레스 문제에 대응하기 위해서 침수저항성 메커니즘과 관련된 다양한 연구가 수행중이다. 침수저항성이 높은 작물을 생산하기 위해서는 침수 스트레스의 여러 요인을 연구하는 것뿐만 아니라 어떻게 식물이 침수스트레스 요인을 감지하고 대응하는 방법을 이해해야 한다. 따라서 본 논문에서는 침수 스트레스 저항성과 관련된 것으로 보고된 작물의 형태적, 생리적, 유전자적 변화에 대해서 소개하고 이를 통해 작물의 침수저항성 메커니즘에 대한 이해를 돕기 위해 내용을 정리하였다.

This research was conducted to evaluate methods of enhancing the waterlogging resistance of soybean plant. Thus, we applied seven types of plant growth regulators (PGRs) to soybean plants and exposed them to waterlogged conditions for a total of 14 days. To evaluate stress resistance, we monitored plant growth characteristics data such as height, chlorophyll content, and chlorophyll fluorescence for 28 days after the initial waterlogging (14 days under waterlogging conditions and 14 days after waterlogging). According to the results, plant height was significantly increased by gibberellin A4 (GA4) treatment compared to the control treatment and waterlogging-only treatment. However, we could not detect plant height owing to plant death when we applied abscisic acid (ABA). Except for GA4 and ABA treatments, plant heights slightly decreased in all treatments compared to the waterlogging-only treatment. The chlorophyll content and chlorophyll fluorescence showed a similar tendency among PGR treatments. The chlorophyll content and chlorophyll fluorescence were significantly increased by ethephon and kinetin treatments 28 days after waterlogging compared to the waterlogging-only treatment. Consequently, kinetin and ethephon treatments induced more resistant phenotypes in soybean plants during or after exposure to waterlogging conditions.