Chen Daoqian, Zhang Hao, Wang Qiongli, Shao Min, Li Xinyu, Chen Dongmei, Zeng Rensen, Song Yuanyuan
Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Agriculture, Fujian Agriculture and Forestry University, Jinshan, Fuzhou 350002, China.
Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Agriculture, Fujian Agriculture and Forestry University, Jinshan, Fuzhou 350002, China.
J Hazard Mater. 2020 Aug 5;395:122672. doi: 10.1016/j.jhazmat.2020.122672. Epub 2020 Apr 12.
Duckweeds are widely recognized for the heavy metal phytoremediation. However, the intraspecific variations in biological responses of duckweeds to heavy metal remain largely unknown. Here, the toxicity and phytoaccumulation of cadmium (Cd) were synchronously evaluated in 30 accessions of giant duckweed (Spirodela polyrhiza) collected from different provenances in Southern China. Exposure to 1 μM Cd decreased relative growth rates of dry weight, fronds number and fronds area, as well as photosynthetic pigment contents, while it increased HO accumulation, lipid peroxidation and activities of anti-oxidant enzymes in the majority of accessions. Cd treatment led to remarkable Cd accumulation but little changes in the starch content in giant duckweed. The biological responses to Cd varied among the accessions. Further correlation analysis indicated that growth traits and Cd concentration were positively correlated with Cd accumulation, while the contents of chlorophyll, HO and MDA were negatively associated with Cd accumulation. Our results proved the great intraspecific variation in Cd tolerance of giant duckweed, suggesting a valuable natural resource for Cd phytoremediation. Moreover, different mechanisms may be exploited by S. polyrhiza for phytoaccumulation, but growth maintenance, Cd uptake and antioxidative enzyme-independent ROS-scavenging under Cd exposure are the common mechanisms contributing to Cd accumulation ability.
浮萍因具有重金属植物修复能力而被广泛认可。然而，浮萍对重金属的生物反应在种内变异情况仍 largely 未知。在此，对采自中国南方不同产地的 30 份紫萍（Spirodela polyrhiza）进行了镉（Cd）毒性和植物积累的同步评估。暴露于 1 μM Cd 会降低干重、叶状体数量和叶状体面积的相对生长速率，以及光合色素含量，而在大多数材料中会增加 HO 积累、脂质过氧化和抗氧化酶活性。Cd 处理导致紫萍中 Cd 显著积累，但淀粉含量变化不大。不同材料对 Cd 的生物反应存在差异。进一步的相关性分析表明，生长性状和 Cd 浓度与 Cd 积累呈正相关，而叶绿素、HO 和 MDA 的含量与 Cd 积累呈负相关。我们的结果证明了紫萍对 Cd 耐受性存在巨大的种内变异，表明其是 Cd 植物修复的宝贵自然资源。此外，紫萍可能利用不同机制进行植物积累，但在 Cd 暴露下维持生长、Cd 吸收和不依赖抗氧化酶的 ROS 清除是其 Cd 积累能力的共同机制。
