Hg、Cd对莼菜越冬芽光合膜光化学活性及多肽组分的影响

Effect of mercury and cadmium on photochemical activity and polypeptide compositions of photosynthetic membranes from winter bud of Brasenia schreberi

研究了重金属Ｈｇ２＋ 、Ｃｄ２ ＋ 对水生植物莼菜越冬芽光合膜叶绿素含量、多肽组分及光化学特性的影响．实验结果表明，经１ ｍ ｍｏｌ／Ｌ 浓度Ｈｇ２ ＋ 处理后，叶片光合膜叶绿素含量、叶绿素ａ／ｂ 值、室温吸收光谱、荧光发射光谱、光系统电子传递活性呈下降趋势；当Ｈｇ２＋ 处理浓度超过２ ｍ ｍｏｌ／Ｌ 时，叶片光合膜叶绿素含量及其它光化学活性显著下降，光合膜多肽组分也产生降解．茎光合膜对Ｈｇ２ ＋ 的敏感程度比叶片低．莼菜越冬芽经不同浓度Ｃｄ２＋ （２、５ 、１０ ｍ ｍｏｌ／Ｌ） 处理后，其光合膜叶绿素含量、光化学活性也产生相应变化，但程度较Ｈｇ２ ＋ 处理弱；同样，其叶片光合膜对Ｃｄ２＋

The effects of Hg 2+ and Cd 2+ on chlorophyll contents, chlorophyll a/b values, absorption spectra, fluorescence emission spectra at room temperature, electron transport activity of photosystem and polypeptides compositions of thylakoid membrane from winter bud of hydrophyte Brasenia schreberi were investigated. The results showed that the chlorophyll content and photochemical activity decreased progressively with an increasing in concentrations of Hg 2+ and Cd 2+ . The effects of Hg 2+ and Cd 2+ on the chlorophyll content and photochemical activity of thylakoid from leaves decreased obviously and the thylakoid membrane polypeptide compositions was defraded. It was also shown that toxic effects of Hg 2+ on Brasenia schreberi winter bud was more significannt than that of Cd 2+ .