고온·오존 복합 스트레스에 대한 소나무 유묘의

기공적 및 비기공적 광합성 제한 반응

심선경1, 이은이1, 우수영1, 이종규2, 곽명자1*, 정효정1, 이문원1

(1서울시립대학교 환경원예학과, 2국립산림과학원 임목자원연구과)

Stomatal and Non-stomatal Limitations of Pinus densiflora Seedlings under Elevated Temperature and Ozone Stress

Sunkyeong Shim1, Euni Lee1, Suyoung Woo1, Jongkyu Lee2, Myeongja Kwak1*,

Hyocheng Cheng1, Munwon Lee1

(1Department of Environmental Horticulture, University of Seoul,

2Department of Forest Bioresources, National Institute of Forest Science)

요약: 본 연구는 기후변화 요인인 고온과 고농도 오존의 복합 스트레스가 소나무(Pinus densiflora) 유묘의 생리적 활성 및 항산화 체계에 미치는 영향을 규명하고자 수행되었다. 4년생 소나무를 대상으로 28일간 대조구(C), 고온(T, 대조구+8°C), 오존(O, 120μg·kg⁻¹), 복합 처리(OT)의 4개 조건에서 실험을 진행하였다. 시기별(14일, 24일차)로 오존 유입량(Fst), 광합성 능력(Vcmax, Jmax), 활성산소종(ROS) 및 막지질 과산화(Malondialdehyde, MDA)를 분석하였다. 처리 초기(14일차), OT 처리구는 고온에 의해 ‘기공 반응 둔화(stomatal sluggishness)’가 발생하면서 기공이 충분히 닫히지 않아 오존 유입량이 가장 높게 나타났다. 이러한 과도한 오존 유입은 후기(24일차)에 피해 임계 수준을 초과하였으며, OT 처리구에서 Vcmax와 Jmax가 급격히 감소하고 ROS의 폭발적 축적과 MDA 증가에 따른 심각한 세포막 손상이 확인되었다.

Abstract: This study investigated the combined effects of elevated temperature and high ozone (O3) on the physiological and antioxidant responses of Pinus densiflora seedlings. Four-year-old seedlings were exposed to four conditions for 28 days in a phytotron: Control (C), Elevated Temperature (T: +8°C), Ozone (O: 120 μg·kg⁻¹), and Combined Treatment (OT). We analyzed ozone uptake (Fst), photosynthetic parameters (Vcmax, Jmax), reactive oxygen species (ROS), and lipid peroxidation (malondialdehyde, MDA) at 14 and 24 days after treatment initiation. At day 14, the OT treatment exhibited the highest stomatal ozone flux due to temperature-induced stomatal sluggishness, which delayed stomatal closure and resulted in excessive ozone uptake. While initial photosynthetic damage was minimal, a critical threshold was reached by day 24. Notably, seedlings under OT showed a sharp decline in carboxylation efficiency (Vcmax) and electron transport capacity (Jmax), accompanied by an explosive accumulation of ROS and severe membrane damage, as indicated by increased MDA levels. Elevated temperature acts as a critical factor that delays stomatal closure—an early defensive response—thereby intensifying ozone uptake in P. densiflora. This mechanism accelerates physiological dysfunction and tissue injury under combined stress conditions, suggesting that future climate scenarios characterized by warming and ozone pollution may pose a major threat to forest health and resilience.

Keywords: Stomatal sluggishness, Critical threshold, Reactive oxygen species (ROS), Lipid peroxidation, Ozone uptake (Fst)

Acknowledgment: This work was supported by the Ministry of Education of the Republic of Korea and the National Research Foundation of Korea (NRF-2021R1A2C2013068).