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植物研究 ›› 2018, Vol. 38 ›› Issue (5): 653-660.doi: 10.7525/j.issn.1673-5102.2018.05.003

• 研究报告 • 上一篇    下一篇

镉胁迫下铵态氮对红树植物秋茄(Kandelia obovata)生理生态特征的影响

李荣玉, 邱国玉, 沈小雪, 柴民伟   

  1. 北京大学深圳研究生院, 环境与能源学院, 深圳 518055
  • 收稿日期:2018-04-30 出版日期:2018-09-15 发布日期:2018-08-31
  • 通讯作者: 邱国玉 E-mail:qiugy@pkusz.edu.cn
  • 作者简介:李荣玉(1976-),男,高级工程师,博士研究生,主要研究方向环境生态学。
  • 基金资助:
    国家自然科学基金(31400446);深圳市科创委基础研究项目(JCYJ20150331100946599,JCYJ20160330095549229)

Effects of Ammonium Nitrogen on Physiological and Ecological Characteristics of Kandelia obovata under Cadmium Stress

LI Rong-Yu, QIU Guo-Yu, SHEN Xiao-Xue, CHAI Min-Wei   

  1. School of Environment and Energy, Shenzhen Graduate School, Peking University, Shenzhen 518055
  • Received:2018-04-30 Online:2018-09-15 Published:2018-08-31
  • Supported by:
    The National Natural Science Foundation of China(31400446);Program of Science and Technology of Shenzhen(JCYJ20150331100946599,JCYJ20160330095549229)

摘要: 城市红树林湿地面临重金属污染和营养元素过量输入的环境问题。其中,镉(Cd)污染具有较高的生态风险,而铵态氮(NH4+-N)是红树林湿地沉积物中氮素的主要赋存形态。本论文采用盆栽实验研究了镉(Cd)胁迫下铵态氮(NH4+-N)对红树植物秋茄(Kandelia obovata)生理生态特征的影响,包括生物量、叶光合参数(净光合速率Pn,气孔导度Gs,胞间CO2浓度Ci和蒸腾速率E)、叶丙二醛(MDA)和可溶性糖含量以及根系活力。结果表明:(1)在单Cd胁迫下,秋茄生物量和蒸腾速率(E)显著降低,但根系活力在较高的单Cd胁迫下显著增加;(2)Cd胁迫下,低浓度NH4+-N显著增加秋茄根生物量,但对地上生物量(Cd3处理的叶和Cd1处理的茎除外)和光合作用(PnGsE)的促进作用不显著;高浓度NH4+-N显著抑制了生物量和光合作用(PnGsE);(3)在Cd1处理下,根系活力随NH4+-N胁迫的增强呈先升高后降低的趋势;在Cd2和Cd3处理下,NH4+-N显著降低了根系活力;(4)Cd胁迫下,低浓度NH4+-N对叶MDA(表征氧化损伤)和叶可溶性糖含量(表征渗透调节)的抑制不显著,高浓度NH4+-N显著降低了MDA和可溶性糖的含量。因此,较低浓度的NH4+-N能够缓解Cd对秋茄地下根的毒害,对地上部分的缓解作用有限;高浓度NH4+-N会与Cd产生协同的复合胁迫,加重对秋茄的毒害。

关键词: 重金属, 营养元素, 红树植物, 光合作用

Abstract: The heavy metal pollution and excess input of nutrient elements become two important environmental problems in mangrove forest. The ecological risk of cadmium(Cd) is relatively high, and ammonium nitrogen(NH4+-N) is the main speciation of nitrogen in sediment of mangrove. In order to clarify the growth and physiological characteristics of Kandelia obovata under combined stresses of Cd and NH4+-N, pot experiments were conducted. Plant growth, leaf photosynthetic parameters(photosynthetic rate(Pn), stomatal conductance(Gs), intercellular CO2 concentration(Ci) and transpiration rate(E)), leaf malondialdehyde(MDA), leaf soluble sugar, and root activity were determined. The results showed that:(1)Plant growth and leaf transpiration rate(E) of K.obovata decreased under single Cd stress, with root activity to be reduced under higher single Cd stress; (2)Under Cd stress, low concentration of NH4+-N significantly improved growth of root, but did not significantly improved growth of aboveground part, and leaf photosynthesis(Pn, Gs and E); while high concentration of NH4+-N significantly reduced plant growth, and leaf photosynthesis(Pn, Gs and E); (3)Under Cd1 treatment, root activity first increased and then decreased with increasing NH4+-N concentration; while reduced root activity were shown under Cd2 and Cd3 treatments with NH4+-N supply; (4)Under Cd stress, low concentration of NH4+-N did not significantly reduce content of malondialdehyde(indicative of oxidative damage) and soluble sugar(indicating osmotic adjustment), while high concentration of NH4+-N significantly reduced the content of MDA and soluble sugar. Therefore, the lower concentration of NH4+-N can alleviate the Cd toxicity to root, with limited emission on aboveground part; while high concentration of NH4+-N and Cd combined stress would have a synergistic effect to aggravate Cd toxicity to K.obovata.

Key words: heavy metal, nutrient element, mangrove plant, photosynthesis

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