锰的植物毒性：旧问题的新见解
Manganese phytotoxicity: new light on an old problem.
作者信息
Fernando Denise R, Lynch Jonathan P
机构信息
Department of Ecology, Environment and Evolution, La Trobe University, VIC 3086, Australia and.
Department of Plant Science, The Pennsylvania State University, University Park, PA 16802, USA
出版信息
Ann Bot. 2015 Sep;116(3):313-9. doi: 10.1093/aob/mcv111.
BACKGROUND
Manganese (Mn) is an essential micronutrient that is phytotoxic under certain edaphic and climatic conditions. Multiple edaphic factors regulate Mn redox status and therefore its phytoavailability, and multiple environmental factors including light intensity and temperature interact with Mn phytotoxicity. The complexity of these interactions coupled with substantial genetic variation in Mn tolerance have hampered the recognition of Mn toxicity as an important stress in many natural and agricultural systems.
SCOPE
Conflicting theories have been advanced regarding the mechanism of Mn phytotoxicity and tolerance. One line of evidence suggests that Mn toxicity ocurrs in the leaf apoplast, while another suggests that toxicity occurs by disruption of photosynthetic electron flow in chloroplasts. These conflicting results may at least in part be attributed to the light regimes employed, with studies conducted under light intensities approximating natural sunlight showing evidence of photo-oxidative stress as a mechanism of toxicity. Excessive Mn competes with the transport and metabolism of other cationic metals, causing a range of induced nutrient deficiencies. Compartmentation, exclusion and detoxification mechanisms may all be involved in tolerance to excess Mn. The strong effects of light, temperature, precipitation and other climate variables on Mn phytoavailability and phytotoxicity suggest that global climate change is likely to exacerbate Mn toxicity in the future, which has largely escaped scientific attention.
CONCLUSIONS
Given that Mn is terrestrially ubiquitous, it is imperative that the heightened risk of Mn toxicity to both managed and natural plant ecosystems be factored into evaluation of the potential impacts of global climate change on vegetation. Large inter- and intraspecific genetic variation in tolerance to Mn toxicity suggests that increased Mn toxicity in natural ecosystems may drive changes in community composition, but that in agroecosystems crops may be developed with greater Mn tolerance. These topics deserve greater research attention.
背景
锰（Mn）是一种必需的微量营养素，但在某些土壤和气候条件下具有植物毒性。多种土壤因素调节锰的氧化还原状态，进而影响其对植物的有效性，而包括光照强度和温度在内的多种环境因素与锰的植物毒性相互作用。这些相互作用的复杂性，加上锰耐受性方面存在大量遗传变异，阻碍了人们将锰毒性视为许多自然和农业系统中的一种重要胁迫。
范围
关于锰植物毒性和耐受性的机制，已经提出了相互矛盾的理论。一系列证据表明，锰毒性发生在叶片质外体中，而另一些证据则表明，毒性是通过破坏叶绿体中的光合电子流而产生的。这些相互矛盾的结果至少部分可归因于所采用的光照条件，在接近自然阳光的光照强度下进行的研究表明，光氧化应激是一种毒性机制。过量的锰与其他阳离子金属的运输和代谢竞争，导致一系列诱导性营养缺乏。区室化、排斥和解毒机制可能都参与了对过量锰的耐受性。光照、温度、降水和其他气候变量对锰的植物有效性和植物毒性有强烈影响，这表明全球气候变化可能会在未来加剧锰毒性，而这在很大程度上尚未得到科学关注。
结论
鉴于锰在陆地普遍存在，在评估全球气候变化对植被的潜在影响时，必须将锰对人工管理和自然植物生态系统毒性增加的风险考虑在内。种间和种内对锰毒性的耐受性存在很大的遗传变异，这表明自然生态系统中锰毒性的增加可能会推动群落组成的变化，但在农业生态系统中，可以培育出对锰耐受性更强的作物。这些主题值得更多的研究关注。
Zotero 插件