| 摘要: |
| 裙带菜于1994年来自威海市俚岛养殖场．1995年2月-1997年3月，用不同浓度（0，1，10，100，1000 μmol/L的Cu2+，Cd2+和Zn2+处理裙带菜配子体，研究这些重金属对其生长和代谢的影响。结果表明，Cu2+对裙带菜配子体生长的抑制效应最强：在1 μmol/L时已出现抑制效应，叶绿素含量和光合作用速率明显下降，脯氨酸和丙二醇含量升高。10 μmol/L时，配子体生长几乎停止；超过10 μmol/L，配干体逐渐变绿，细胞解体死亡．Cd2+在1 μmol/L浓度时，对裙带菜配子体生长有促进作用；100 μmol/L时，对配子体生长、叶绿素含量、光合作用具较强的抑制作用，其抑制程度与Cu2+ 1 μmol/L浓度相似；1000 μmol/L下，配子体细胞很快死亡。Zn2+对裙带菜配子体的毒性很小；1000 μmol/L时，仍有缓慢生长．这3种金属闻子毒性强弱的顺序是Cu2+＞Cd2+＞Zn2+。 |
| 关键词: 裙带菜 配子体 重金属离子 生长 毒性 |
| DOI： |
| 分类号: |
| 基金项目:国家自然科学基金资助项目，39670584号;国家攀登计划B资助项目，PD-B-6-4-2号;山东省科委资助项目，961165301号 |
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| A STUDY ON TOLERANT CAPACITY OF UNDARIA PINNATIFIDA GAMETOPHYTE TO THE TOXICITY OF THREE HEAVY METAL IONS |
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H0U He-sheng,LI Ning,WU Chao-yuan,LIU Hai-hang
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1.Insititule of Oceanology, The Chinese Academy of deiences, Qingdao, 266071;2.DePartment of Biology, ne Hong Kong University of sience and Technology, Hong Kong
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| Abstract: |
| Sporophytes of U. pinnarifida were collected from Lidao, Weihai in 1994. Gametophytes from the sporophytes were maintained in enriched seawater. To investigate into the effect of heavy metal ions on the growth from February l995 to March 1997, the gametophytes were cultured in PESI medium treated with Cu2+, Cd2+ and Zn2+ at 0, 1,10, 100, 1000 μmol/L concentrations. For the study of the influences of the metal ions on chlorophyll content, photosynthetic rate, proline and malondialdehyde (MDA) content of the gametophytes, the PESI medium treated with the ions at 0, 5, 20, 40, 60, 80, l00 μmol/L was employed. The culture condition was 25°C, 3000 lx, 12:12h light: dark cycle. The intervals of measurement was 7 days far growth and 4 days for physiological study.
Copper, among the three metal ions investigated, was the most toxic metal ion to the gametophyte. A 50% reduction in growth took place when copper concentration was slightly higher than 1 μmol/L. Growth of the gametophyte stopped after 4 days’ treatment at 10 μmol/L. The color of the cells changed from brown to green and the cells disintegrated rapidly when Cu2+ concentration 10 μmol/L. Cd2+ might facilitate the growth at low concentration (1 μmol/L), but started to retard the growth at l0 μmol/L. The growth rate of the gametophyte was reduced by 50% at 100 μmol/L Cd2+. The gametophytes died gradually at 1000 μmol/L Cd2+. Zn2+ had little negative effect on the gametophyte even at 100 μmol/L but the growth was obviously inhibited at 1000 μmol/L (Fig.1).
After 12 days' treatment at 5 μmol/L Cu2+, the chlorophyll content decreased by 20.3% and photosynthetic rate was 44.6% lower than that in the control. After 16, 12 and 8 days of the treatment at 60, 80, 100 μmol/L Cu2+ respectively, the gametophytes died (Tab. 1). The toxic effect of Cd2+ on the chlorophyll content and the photosynthetic rate was stronger in 5 μmol/L, 16 days' treatment group than in 80 μmol/L, 4 days' treatment group. This result indicated that Cd2+ might accumulate in the gametophytes during the treatment period. Zn2+ had a much less toxic effect on the gametophyte than Cu2+ and Cd2+. 100 μmol/L Cd2+, 16 days’ treatment could make 42.9% and 36.5% reductions of chlorophyll content and photosynthetic rates of the gametophytes, respectively. Proline and MDA contents in the gametophytes treated with 100 μmol/L Cu2+ for 4 days were 4.5 and 14 times higher than those in the controls. In the gametophytes treated with 100 μmol/L Cd2+ or Zn2+ for 16 days, proline and MDA were 3 and 12 times or 1.7 and 2.7 times higher than those in the controls. The order of the metal ions toxicity is Cu2+ >Cd2+>Zn2+.
The results showed that pollution of Cu2+ in coastal areas may cause damages in the cultivation of the alga. The lethal Cu2+ and Cd2+ concentrations for the gametophyte have been identified; such concentrations can be used to screen the transgenic cells of the gametophyte, which are integrated with metallothionein gene. |
| Key words: Undaria pinnatifida, Gametophyte, Heavy metal ions, Growth Toxicity |
