Fe^(2+)胁迫对西洋参某些生理指标的影响

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

为了明确Fe2+胁迫对西洋参某些生理指标的影响,以土壤为基质外施FeSO4进行盆栽试验,土壤添加Fe2+浓度分别为0(CK)、112、224、336、448和560 mg·kg-1。试验结果表明:叶片中叶绿素a、叶绿素b、类胡萝卜素含量均随土壤中Fe2+浓度增加呈现出下降趋势,在土壤添加Fe2+浓度为560 mg·kg-1时最低,分别为1.338、0.704和0.458 mg·g-1,且各处理均显著低于对照(P<0.05)。在Fe2+胁迫下,脯氨酸含量、MDA含量、POD活性、CAT活性均随土壤中Fe2+浓度增加呈现出先升高后降低的趋势,其中脯氨酸含量在土壤添加Fe2+浓度为336 mg·kg-1时最高,为64.928 mg·g-1,显著高于其它胁迫处理(P<0.05),MDA含量和POD活性在土壤添加Fe2+浓度为448 mg·kg-1时最高,分别为3.958μmol·g-1、333.555 U·g-1·min-1,CAT活性则是在外加Fe2+浓度为224 mg·kg-1时最高,为118.051 U·g-1·min-1。各生理指标相关性分析结果显示叶绿素a、叶绿素b、类胡萝卜素彼此间呈极显著正相关,叶绿素含量与MDA含量、POD活性呈极显著负相关,MDA含量与POD活性呈极显著正相关,Fe2+胁迫下西洋参体内各生理指标相互影响、互相作用。总之,在Fe2+胁迫下西洋参体内生理指标受到影响,一定范围内的Fe2+会诱导渗透调节系统和体内相应酶活性的增加减缓或降低Fe2+胁迫对西洋参的影响,维持正常生理代谢,从而表现出一定的抗铁毒能力。

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 deereaced 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^-1 treatment were respectively 3. 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^-1 treatment 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 cor- relation 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.