在低资源环境下,植物的生物量分配模式或表型的可塑性暗示着环境信号和个体发育之间存在复杂的相互作用关系,而不仅仅是植物发育上的延迟(个体发育漂变)。要理解环境因子对生物量分配模式或表型的影响,就必须区分生物量分配模式是来源于环境梯度还是个体发育漂变。
近日,PLoS ONE发表了中国科学院新疆生态与地理研究所李彦研究员团队的发现,土壤质地显著改变了往叶和根的生物量分配比例,但是没有影响往茎的生物量分配比例;同时,土壤质地也显著改变了叶和根特征的发育轨线,但没有影响基茎直径和植株高度之间的异速生长关系。
研究人员通过构建Nested-ANOVAs模型确认,土壤质地梯度对叶和根生物量分配比例变异的贡献平均可以达到64–70%,远大于个体发育漂变的贡献(14%)。而个体发育漂变对茎生物量分配比例变异的贡献平均可以达到77%,远大于环境梯度的贡献(20%-28%)。
这些结果暗示着环境因子主导着往叶和根的生物量分配,而个体发育漂变控制着往茎的生物量分配。换句话说,植物往代谢活跃器官的生物量分配主要受环境因素的影响,对环境变化敏感,具有高的可塑性;而代谢非活跃器官的生物量分配主要受控于个体发育漂变,对环境变化不敏感,具有较低的可塑性。(生物谷Bioon.com)
doi:10.1016/j.cell.2011.10.017
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Distinguishing the Biomass Allocation Variance Resulting from Ontogenetic Drift or Acclimation to Soil Texture
Jiangbo Xie1,2, Lisong Tang1, Zhongyuan Wang1,2, Guiqing Xu1, Yan Li1*
In resource-poor environments, adjustment in plant biomass allocation implies a complex interplay between environmental signals and plant development rather than a delay in plant development alone. To understand how environmental factors influence biomass allocation or the developing phenotype, it is necessary to distinguish the biomass allocations resulting from environmental gradients or ontogenetic drift. Here, we compared the development trajectories of cotton plants (Gossypium herbaceum L.), which were grown in two contrasting soil textures during a 60-d period. Those results distinguished the biomass allocation pattern resulting from ontogenetic drift and the response to soil texture. The soil texture significantly changed the biomass allocation to leaves and roots, but not to stems. Soil texture also significantly changed the development trajectories of leaf and root traits, but did not change the scaling relationship between basal stem diameter and plant height. Results of nested ANOVAs of consecutive plant-size categories in both soil textures showed that soil gradients explained an average of 63.64–70.49% of the variation of biomass allocation to leaves and roots. Ontogenetic drift explained 77.47% of the variation in biomass allocation to stems. The results suggested that the environmental factors governed the biomass allocation to roots and leaves, and ontogenetic drift governed the biomass allocation to stems. The results demonstrated that biomass allocation to metabolically active organs (e.g., roots and leaves) was mainly governed by environmental factors, and that biomass allocation to metabolically non-active organs (e.g., stems) was mainly governed by ontogenetic drift. We concluded that differentiating the causes of development trajectories of plant traits was important to the understanding of plant response to environmental gradients.