Exposure to cadmium causes declines in growth and photosynthesis in the endangered aquatic fern (Ceratopteris pteridoides)
Exposure to cadmium causes declines in growth and photosynthesis in the endangered aquatic fern (Ceratopteris pteridoides)
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接触镉会导致濒临灭绝的水生蕨类植物（Ceratopteris pteridoides）的生长和光合作用下降
DOI：
10.1016/j.aquabot.2013.07.003
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发表时间：
2014-01-01
期刊：
影响因子：
1.8
通讯作者：
Li, Wei
中科院分区：
文献类型：
--
作者：
Deng, Guang;Li, Ming;Li, Wei
随着农业和城市化的快速发展，我国的水生生态系统和水生植物面临着重金属污染的严重威胁，在某些重金属污染的沃茨中，有毒污染物镉（Cd）的浓度高达4500 μ g l（-1）。我们的目标是评估与濒危水生物种Ceratopteris pteridoides种群下降相关的水生系统中重金属Cd的生物学原因。研究了镉（Cd）胁迫对紫茎泽兰光合性能、叶绿素含量、抗氧化酶活性和氮代谢的影响。在温室条件下研究了Pteridoides。幼苗暴露于各种镉浓度（0，5，10，20，和40亩M）为7天。Cd离子在植物组织中的积累通过抑制净同化率和降低叶面积比抑制了蕨草的相对生长速率。在20和40 μ M镉浓度C pteridoides生物量显着减少。Cd胁迫严重限制了植物的净光合速率。镉处理植物光合作用的限制因素更多地与非气孔限制有关。Cd处理降低了叶绿素含量，也影响了植物核酮糖-1，5-二磷酸（RuBP）活性和再生能力。Cd胁迫下叶片光合作用下降表明，大量的Rubisco在光合作用中不活跃。Cd处理显著降低了PSII的相对量子效率、电子传递速率和PSII反应中心的光化学效率，这与Rubisco活性的降低相对应。增加镉浓度表现出类似的影响，超氧化物歧化酶，过氧化氢酶，过氧化物酶活性的叶和根。此外，镉滞留引起的细胞膜损伤，表现为丙二醛含量增加镉毒性可能干扰植物营养同化，因为有氮素吸收和转运的不足，表现为硝酸还原酶和谷氨酰胺合成酶活性降低。我们的结论是，在镉胁迫植物的生理干扰与所观察到的植物生长抑制是一致的。植物镉胁迫抑制了锦鸡儿的氮素吸收和光合作用。pteridoides，从而增加其死亡风险。有效的策略，以恢复这种濒危蕨类植物的环境质量意味着减少镉污染的环境。(C)2013年由Elsevier B. V.出版
With rapid development of agriculture and urbanization, aquatic systems and aquatic plants in China face a great threat of heavy metal pollution where toxic contaminant cadmium (Cd) concentrations were reported up to 4500 mu g l(-1) in some heavy metal polluted waters. Our objectives were to assess the biological causes of heavy metal Cd in aquatic systems associated with the population decline of an endangered aquatic species Ceratopteris pteridoides. The effects of cadmium (Cd) toxicity on the photosynthetic performance, leaf chlorophyll content, antioxidant enzyme activities and nitrogen metabolism in C. pteridoides were investigated under greenhouse conditions. Seedlings were exposed to various Cd concentrations (0, 5, 10, 20, and 40 mu M) for 7 days. The accumulation of Cd ions in plant tissues inhibited the relative growth rate of C pteridoides through net assimilation rate retardation and leaf area ratio reduction. A significant reduction in biomass was observed in C pteridoides at 20 and 40 mu M Cd concentrations. Exposure to Cd severely restricted plant net photosynthetic rates. Factors limiting photosynthesis in Cd-treated plants were more related to non-stomatal constraints than to stomatal limitation. Cd reduced chlorophyll content of the treated plants and affected also plant ribulose-1,5-bisphosphate (RuBP) activity and regeneration capacity. Decreased leaf photosynthesis showed that a significant amount of Rubisco was not active in photosynthesis under Cd stress. The Cd treatments reduced significantly the relative quantum efficiency of PSII, electron transport rate and photochemical efficiency of PSII reaction centers, which corresponded to the reduction in Rubisco activity. Increased Cd concentrations showed similar effects on the superoxide dismutase, catalase, and peroxidase activities in the leaves and roots. Also, Cd retention caused cell membrane damage shown by increased malondialdehyde content Cd toxicity may have interfered with plant nutritional assimilation because there was a deficiency in nitrogen uptake and translocation, shown by the reduced nitrate reductase and glutamine synthetase activities. We conclude that physiological disturbances in Cd-stressed plants are congruent with the observed plant growth inhibition. Plant Cd stress inhibited both nitrogen absorption and photosynthesis in C. pteridoides, thus enhancing its mortality risk. An efficient strategy to restore environmental quality for this endangered fern implies the reduction of Cd pollution in the environment. (C) 2013 Published by Elsevier B.V.