Cui Xinglei, Paterson Adrian M, Alam Md Azharul, Wyse Sarah V, Marshall Kate, Perry George L W, Curran Timothy J
Department of Pest-management and Conservation, Lincoln University, Lincoln, 7647, New Zealand.
Bio-Protection Research Center, Lincoln University, Lincoln, 7647, New Zealand.
New Phytol. 2020 Oct;228(1):95-105. doi: 10.1111/nph.16651. Epub 2020 Jun 11.
Plant flammability varies across species, but the evolutionary basis for this variation is not well understood. Phylogenetic analysis of interspecific variation in flammability can provide insights into the evolution of plant flammability. We measured four components of flammability (ignitability, sustainability, combustibility and consumability) to assess the shoot-level flammability of 21 species of Dracophyllum (Ericaceae). Using a macroevolutionary approach, we explored phylogenetic patterns of variation in shoot-level flammability. Shoot-level flammability varied widely in Dracophyllum. Species in the subgenus Oreothamnus had higher flammability and smaller leaves than those in the subgenus Dracophyllum. Shoot flammability (ignitability, combustibility and consumability) and leaf length showed phylogenetic conservatism across genus Dracophyllum, but exhibited lability among some closely related species, such as D. menziesii and D. fiordense. Shoot flammability of Dracophyllum species was negatively correlated with leaf length and shoot moisture content, but had no relationship with the geographic distribution of Dracophyllum species. Shoot-level flammability varied widely in the genus Dracophyllum, but showed phylogenetic conservatism. The higher flammability of the subgenus Oreothamnus may be an incidental or emergent property as a result of the evolution of flammability-related traits, such as smaller leaves, which were selected for other functions and incidentally changed flammability.
植物的可燃性因物种而异，但这种变异的进化基础尚未得到很好的理解。对可燃性种间变异进行系统发育分析，有助于深入了解植物可燃性的进化。我们测量了可燃性的四个组成部分（易燃性、持续性、 combustibility和consumability），以评估21种吊钟花属（杜鹃花科）植物地上部分的可燃性。我们采用宏观进化方法，探究了地上部分可燃性变异的系统发育模式。吊钟花属植物地上部分的可燃性差异很大。Oreothamnus亚属的物种比Dracophyllum亚属的物种具有更高的可燃性和更小的叶子。整个吊钟花属中，地上部分可燃性（易燃性、combustibility和consumability）以及叶长表现出系统发育保守性，但在一些近缘物种中，如Menziesii吊钟花和峡湾吊钟花，表现出易变性。吊钟花属植物的地上部分可燃性与叶长和地上部分含水量呈负相关，但与吊钟花属物种的地理分布无关。吊钟花属植物地上部分的可燃性差异很大，但表现出系统发育保守性。Oreothamnus亚属较高的可燃性可能是与可燃性相关性状进化的偶然或衍生特性，比如较小的叶子，这些叶子因其他功能而被选择，可燃性也随之偶然改变。
