Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA.
The Arnold Arboretum, Boston, Massachusetts, USA.
Plant Cell Environ. 2021 Aug;44(8):2494-2505. doi: 10.1111/pce.13959. Epub 2021 Apr 29.
Trees' total amount of non-structural carbohydrate (NSC) stores and the proportion of these stores residing as insoluble starch are vital traits for individuals living in variable environments. However, our understanding of how stores vary in response to environmental stress is poorly understood as the genetic component of storage is rarely accounted for in studies. Here, we quantified variation in NSC traits in branch samples taken from over 600 clonally transplanted black cottonwood (Populus trichocarpa) trees grown in two common gardens. We found heritable variation in both total NSC stores and the proportion of stores in starch (H = 0.19, H = 0.31), indicating a substantial genetic component of variation. In addition, we found high amounts of plasticity in both traits in response to cold temperatures and significant genotype-by-environment (GxE) interactions in the total amount of NSC stored (54% of P is GxE). This finding of high GxE indicates extensive variation across trees in their response to environment, which may explain why previous studies of carbohydrate stores' responses to stress have failed to converge on a consistent pattern. Overall, we found high amounts of environmental and genetic variation in NSC storage concentrations, which may bolster species against future climate change.
树木中非结构性碳水化合物（NSC）的总量以及这些储存物中不溶性淀粉的比例，对于生活在多变环境中的个体来说是至关重要的特征。然而，由于研究中很少考虑到储存的遗传成分，我们对储存物如何响应环境压力而变化的理解还很有限。在这里，我们对在两个常见的园林中种植的 600 多株克隆移植的黑杨（Populus trichocarpa）树枝样本中的 NSC 特性进行了定量分析。我们发现，总 NSC 储存量和淀粉储存比例都存在可遗传的变异（H = 0.19，H = 0.31），这表明变异存在很大的遗传成分。此外，我们发现，这两个特性都对低温表现出了很高的可塑性，并且在储存的总 NSC 量方面存在显著的基因型与环境互作（GxE，占 P 的 54%）。这种高 GxE 的发现表明，树木对环境的反应存在广泛的差异，这可能解释了为什么以前关于碳水化合物储存物对压力的反应的研究未能得出一致的模式。总的来说，我们发现 NSC 储存浓度存在大量的环境和遗传变异，这可能增强了物种对未来气候变化的适应能力。
