Institute of Environment and Ecology, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, 212013, PR China; Institute of Agricultural Engineering, Jiangsu University, Xuefu Road 301, Zhenjiang, 212013, PR China.
Institute of Environment and Ecology, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang, 212013, PR China.
Environ Pollut. 2020 Dec;267:115649. doi: 10.1016/j.envpol.2020.115649. Epub 2020 Sep 14.
Invasive plants readily invade metal-contaminated areas. The hyperaccumulation of toxic heavy metals is not an uncommon feature among plant species. Although several hypotheses were proposed to explain this phenomenon, it is currently unclear how hyperaccumulation may benefit plants. The invasive Crofton weed (Ageratina adenophora) is a known hyperaccumulator of chromium and lead. We previously found that the species can also hyperaccumulate cadmium. The role of phytoaccumulation in defense to pathogen attack is unclear. We inoculated A. adenophora plants with a common generalist pathogen (Rhizoctonia solani) to test its resistance under cadmium treatment. We found evidence that cadmium hyperaccumulation reduced pathogen infection in A. adenophora. Our findings indicate elemental defense is highly cost efficient for hyperaccumulators inhabiting metal-contaminated sites, where plants were only modestly affected by cadmium. The reduction in pathogen damage conferred by cadmium was relatively high, particularly under lower cadmium levels. However, the benefits at higher levels may be capped. Elemental defense may be a key mechanism for plant invasion into polluted sites, especially in regions with widespread industrial activity. Our study highlights the importance of testing different metal concentrations when testing plant resistance and the importance of considering enemy attack when selecting plants for phytoremediation.
入侵植物很容易侵入受金属污染的地区。有毒重金属的超积累在植物物种中并不罕见。尽管提出了几种假说来解释这种现象，但目前尚不清楚超积累如何使植物受益。入侵的Crofton 杂草（Ageratina adenophora）是铬和铅的已知超积累植物。我们之前发现该物种还可以超积累镉。植物对病原体攻击的积累作用尚不清楚。我们用一种常见的泛化病原体（Rhizoctonia solani）接种 A. adenophora 植物，以在镉处理下测试其抗性。我们有证据表明，镉的超积累减少了 A. adenophora 中的病原体感染。我们的研究结果表明，对于生活在受金属污染的地方的超积累者来说，元素防御是非常高效的，因为这些植物只受到轻微的镉影响。由镉引起的病原体损害减少相对较高，特别是在较低的镉水平下。然而，在更高的水平上，收益可能会受到限制。元素防御可能是植物入侵污染地的关键机制，尤其是在工业活动广泛的地区。我们的研究强调了在测试植物抗性时测试不同金属浓度的重要性，以及在选择用于植物修复的植物时考虑敌害攻击的重要性。
