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生态学杂志 ›› 2012, Vol. 31 ›› Issue (11): 2828-2833.

• 研究报告 • 上一篇    下一篇

镉在泰来藻体内的累积规律及对光合作用的影响

冯韶辉1,2,3,黄小平1**,江志坚1,3   

  1. (1中国科学院南海海洋研究所热带海洋环境国家重点实验室, 广州 510301; 2中国科学院研究生院, 北京 100049; 3中国科学院海南热带海洋生物实验站, 海南三亚 572000)
  • 出版日期:2012-11-10 发布日期:2012-11-10

Cadmium accumulation and its effects on the photosynthesis of Thalassia hemprichii.

FENG Shao-hui1,2,3, HUANG Xiao-ping1**, JIANG Zhi-jian1,3   

  • Online:2012-11-10 Published:2012-11-10

摘要: 采用化学逐步提取法和叶绿素荧光技术,在实验室无底泥条件下研究了镉(Cd)在热带海草泰来藻(Thalassia hemprichii)不同组织(叶、茎、根)中的累积规律,以及Cd对其光合作用的影响。结果表明:Cd在泰来藻体内的累积模式是叶>根>茎;在各处理条件下,泰来藻各组织中氯化钠、醋酸和盐酸提取态的Cd均是优势形态,三者之和占总量的80%~99%,表明活性较低且迁移能力较弱的形态是主要形态;随着Cd暴露浓度的增加,泰来藻各组织中盐酸提取态所占的比例下降7%~24%,而氯化钠和醋酸提取态的分配比例总和增加2%~24%,叶片中活性较高的乙醇和水提取态所占比例之和不断减小,而茎、根则呈现相反的趋势,这说明泰来藻通过改变各形态Cd在细胞和组织中的分配比例来降低高浓度Cd胁迫的毒性;高浓度Cd胁迫显著降低有效光量子产量ΔF/Fm′、叶绿素a、b和总叶绿素含量,表明其光合作用受到严重抑制。总之,在较低浓度Cd胁迫下,泰来藻存在一定的保护机制,但在高浓度Cd胁迫下,这种保护机制已不足以维持内环境的稳定,从而引起一系列毒性效应。

关键词: 氮肥喷涂吡啶, 夏玉米, N2O排放, 产量, 氮素利用

Abstract: By the methods of sequential extraction and chlorophyll fluorescence, a laboratory experiment with no sediments was conducted to study the cadmium (Cd) accumulation in different organs of tropical seagrass Thalassia hemprichii and the effects of Cd on the photosynthesis of the seagrass. The Cd accumulation in T. hemprichii organs was in the order of leaf > root > rhizome. In all treatments, the Cd in the T. hemprichii organs was dominated by the 1 mol·L-1 NaCl-, 2% HAc-, and 0.6 mol·L-1 HClextractable Cd, occupying 80%-99% of the total Cd, indicating that the less active and weakly migrated forms were the main forms of Cd in T. hemprichii. Under the exposure of increasing concentration Cd, the proportion of 0.6 mol·L-1 HClextractable Cd in different organs of T. hemprichii decreased by 7%-24%, while the proportion of 1 mol·L-1 NaCl and 2% HAcextractable Cd increased by 2%-24%. On the other hand, the 80% ethanol and dH2Oextractable Cd, the high active Cd forms, decreased in T. hemprichii leaf but increased in root and rhizome. These results suggested that T. hemprichii could weaken the toxicity of Cd by changing the proportion of different Cd forms in cells and/or organs. Under the exposure of high concentration Cd, the effective quantum yield (ΔF/Fm′) and the chlorophyll a, chlorophyll b and total chlorophyll contents declined significantly, suggesting that the photosynthesis of T. hemprichii was seriously impaired. It seemed that the protective mechanisms evolved by T. hemprichii could play an important role in Cd detoxification when exposed to relatively low concentration Cd, but became restricted under higher Cd stress.

Key words: nitrapyrin-N fertilizer, summer maize, N2O emission, yield, N utilization.