The effects of Cd2+ ions on the Chl a fluorescence of 5 hydrophytes (e.g. Lemna, Salvinia, Ricciocarp, Nymph, Typha plants) were investigated in order to select Cd2+-sensitive plant species and to get informations on physiological responses of plants to Cd2+ stress. Lemna plants were most sensitive to cadmium stress, while Nymph plants were tolerant. However, in all Cd2+-treated plants, Fv/Fm, the maximum photochemical efficiency of PSⅡ, decreased in proportion to the increase of Cd2+ concentration and treatment time. The Chl a fluorescence transient O-J-I-P was also considerably affected by Cd2+ ions; the fluorescence yield decreased considerably in steps J, I and P in Cd2+ treated plants, although it followed a typical polyphasic rise in non-treated plants. In Lemna plants, the functional parameters, ABS/CS, TRo/CS와 ETo/CS and RC/CS, decreased in proportion to the increase of Cd2+ concentration, while N, Mo and Kn increased. The structural parameters, Φpo, Φpo/(1-Φpo), Plabs, SFlabs, Kp and RC/ABS, also decreased according to the increase of Cd2+ concentration. Consequently, Lemna plants will be useful as a experimental model system to investigate responses of plants. And several functional or structural parameters could be applied to determine quantitatively the physiological states of plants under stresses.

Abstract
 1. 서 론
 2. 재료 및 방법
  2.1. 식물재료
  2.2. 배지제조 및 배양
  2.3. 카드뮴 처리
  2.4. 광합성효율 분석
 3. 결과 및 고찰
  3.1. 카드뮴 스트레스에 의한 수생식물 5종의형광이미지의 변화
  3.2. 카드뮴 스트레스에 의한 좀개구리밥의 엽록소형광의 변화
 4. 결 론
 참 고 문 헌

• 오순자(제주대학교 생물학과/기초과학연구소) | Soonja Oh (Department of Biology & Research Institute for Basic Sciences, Jeju National University) Corresponding Author
• 진국림(제주대학교 생물학과/기초과학연구소) | Kook Lhim Zhin (Department of Biology & Research Institute for Basic Sciences, Jeju National University)
• 고석찬(제주대학교 생물학과/기초과학연구소) | Seok Chan Koh (Department of Biology & Research Institute for Basic Sciences, Jeju National University)