Umbach Ann L, Lacey Elizabeth P, Richter Scott J
DCMB Group/Biology Department, Box 90338, Duke University, Durham, NC, 27708, USA.
New Phytol. 2009;181(3):662-71. doi: 10.1111/j.1469-8137.2008.02683.x. Epub 2008 Nov 14.
In many plant species, the alternative respiratory pathway consisting of alternative oxidase (AOX) is affected by growth temperature. The adaptive significance of this temperature-sensitivity is unresolved. Here, leaf and spike (flower cluster) AOX protein content and spike/floral reflectance of genotypes from European Plantago lanceolata populations found in regions differing in reproductive season temperatures were measured. Cloned genotypes grown at controlled warm and cool temperatures were used to assess the natural within- and between-population variation in AOX content, temperature-sensitive phenotypic plasticity in content, and the relationship between AOX and temperature-sensitive floral/spike reflectance. AOX content and plasticity were genetically variable. Leaf AOX content, although greater at cool temperature, was relatively low and not statistically different across populations. Spike AOX content was greater than in leaves. Spike AOX plasticity differed significantly among populations and climate-types and showed significant negative correlation with floral reflectance plasticity, which also varied among populations. Genotypes with more AOX at cool than at warm temperature had greater floral reflectance plasticity; genotypes with relatively more AOX at warm temperature had less floral reflectance plasticity. The data support the hypothesis that plasticity of AOX content in reproductive tissues is associated with long-term thermal acclimatization.
在许多植物物种中，由交替氧化酶（AOX）组成的交替呼吸途径受生长温度影响。这种温度敏感性的适应性意义尚未明确。在此，对在生殖季节温度不同的地区发现的欧洲披针叶车前种群的基因型的叶片和穗（花簇）AOX蛋白含量以及穗/花反射率进行了测量。利用在受控的温暖和凉爽温度下生长的克隆基因型来评估AOX含量的自然种群内和种群间变异、含量的温度敏感表型可塑性，以及AOX与温度敏感的花/穗反射率之间的关系。AOX含量和可塑性具有遗传变异性。叶片AOX含量虽然在凉爽温度下更高，但相对较低，且在不同种群间无统计学差异。穗AOX含量高于叶片。穗AOX可塑性在不同种群和气候类型间存在显著差异，且与花反射率可塑性呈显著负相关，花反射率可塑性在不同种群间也有所不同。在凉爽温度下比温暖温度下具有更多AOX的基因型具有更大的花反射率可塑性；在温暖温度下具有相对更多AOX的基因型具有较小的花反射率可塑性。这些数据支持了生殖组织中AOX含量的可塑性与长期热适应相关的假说。
