Effects of Fe~(2+) Stress on Some Physiological Characters of Panax quinquefolium

The aim of the experiment was to study the effects of different Fe2+ stress on physiological characters of American ginseng by adding FeSO4 in the soil. The adding Fe2+ concentration were 0( CK),112,224,336,448 and 560 mg·kg- 1. The results showed that the contents of chlorophyll a,chlorophyll b and carotenoid decreased with increasing of the concentration of Fe2+ ,that the values 1. 338,0. 704,0. 458 mg·g- 1 were the lowest in the concentration of 560 mg·kg- 1. All the content of pigment were lower than that of the control group( P 0. 05). The content of Proline and Malondialdehyde( MDA),the activity of Peroxide( POD) and catalase( CAT) increased at first and then decreaced with increasing of the concentration of Fe2+ ,and the content of proline 64. 928 in 336 mg·kg- 1was the highest,significantly higher than other treatments( P 0. 05). The content of MDA and the activity of POD in 448 mg·kg- 1treatment were respectively3. 958 μmol·g- 1,333.555 U·g- 1·min- 1,which were higher than other treatments. The activity of CAT in 224 mg·kg- 1treatment was 118. 051 U·g- 1·min- 1,which was higher than other treatments. The correlation results of the physiological indexes showed that the chlorophyll a,chlorophyll b and carotenoid were significantly positive correlation with each other. Chlorophyll was significantly negative correlation with the content of MDA and the activity of POD. The content of MDA was significantly positive correlation with the activity of POD.The physiological parameters of American ginseng interact with each other under Fe2+ stress. In a word,physiological response of American ginseng were affected under high iron stress and it would start osmotic regulation system and corresponding enzymes to reduce the influence,maintain normal physiological metabolism,suggesting that it has resistance ability to the iron toxicity.