Fire as a Potent Mutagenic Agent Among Plants

First author: Tianhua He; Affiliations: Curtin University (科廷大学): Perth, Australia

Corresponding author: Tianhua He

Many of the earth's species-rich floras are fire-prone and current research is showing a key role for fire in their evolution and diversification. However the mechanisms by which fire might direct evolution at the cellular level are unknown. Mutagenesis is the foundation on which speciation is based and our literature survey shows that burning biomass may be a major source of potent mutagens (诱变剂) in the form of heat, combustion products and recycled metals and radionuclides (放射性核素). Even mild heat may cause dysfunctional cell division and induce diploid gametes and genome duplication that are considered one of the cornerstones (基石) of speciation among flowering plants. Plant cell walls that undergo pyrolysis (热解) yield particulates (微粒) and gases with strong mutagenic properties, among which polycyclic aromatic hydrocarbons (多环芳香烃), such as benzo[α]pyrene (苯并芘), are notable. Plants concentrate essential, nonmetabolic, and radioactive metal/metalloid ions from the soil and air; they are fractionated even further on combustion (燃烧) and may also have mutagenic effects on the chromosomes of stored seeds and regenerating plants. Morphological consequences may be profound, even mimicking traits present among other species in the lineage, and hold promise that fire-related mutagenesis may provide the missing mechanistic explanation for the close historical association between wildfire and speciation among seed plants.

地球上许多物种丰富的植物区系都处在火灾易发地区，现在的研究表明火在物种演化和分化过程中扮演着非常重要的作用。然而，火直接在细胞层面作用于演化的分子机制还不清楚。突变是物种形成的基础，作者查阅文献显示生物量的燃烧通过热释放、燃烧产物、循环的金属离子及放射性核素的方式成为潜在促突变的主要来源。即使是轻微的热量也会导致细胞分裂的功能紊乱，诱导二倍体配子和基因组复制，这些都是被认为是开花植物物种形成的基础。植物细胞壁经过高温分解会产生微粒和气体，这些产物带有强烈的致突变成分，其中苯并芘之类的多环芳香烃是最为效果显著的。植物从土壤和空气中富集大量的、非代谢的、且具有放射性的金属离子，它们在燃烧的过程中被进一步的分馏，可能对于贮藏的种子和再生的植株具有导致突变的效应。形态学上的结果可能是影响深远的，即使来自支系其它物种上微弱的位点存在与火相关的突变，也可能为野火与种子植物物种形成之间密切的历史关联提供某种解释。

通讯：Tianhua He (http://peeg-curtin.com/people/tianhua-he/)

个人简介：1995年，华中农业大学，农学学士；1999年，北京大学，植物学博士。

研究方向： 植物功能性状的起源与演化；植物对于气候改变的适应性演化；生物多样性的动态变化和维持；保护遗传学；分子和演化生态学。

doi: https://doi.org/10.1080/07352689.2018.1453981

Journal: Critical Reviews in Plant Sciences

Published online: 02 April, 2018

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