Institute of Botany of the Czech Academy of Sciences, Dukelská 135, 379 01 Třeboň, Czech Republic.
Department of Botany, Charles University, Benátská 2, 128 01 Prague, Czech Republic.
Ann Bot. 2023 Nov 30;132(5):1021-1032. doi: 10.1093/aob/mcad158.
Several lines of evidence indicate that carbohydrate storage in plant below-ground organs might be positively related to genome size because both these plant properties represent resource sinks and can affect cell size, cell cycle time, water-use efficiency and plant growth. However, plants adapted to disturbance, such as root sprouters, could be an exception because their strategy would require higher carbohydrate reserves to fuel biomass production but small genomes to complete their cell cycles faster.
We used data from a field survey to test the relationship between genome size and the probability of root sprouting ability in 172 Central European herbaceous species. Additionally, we conducted a pot experiment with 19 herbaceous species with different sprouting ability (nine congeneric pairs plus one species), and measured root non-structural carbohydrate concentrations and pools at the end of a growing season.
In the Central European flora, the probability of root sprouting ability was lower in large-genome species but this pattern was weak. In the pot experiment, both total non-structural and water-soluble carbohydrates (mainly fructans) were positively and non-linearly related to genome size, regardless of sprouting strategy. The concentrations of mono- and disaccharides and all carbohydrate pools showed no link to genome size, and starch was absent in large-genome species. The link between genome size and carbohydrate storage was less apparent at a small phylogenetic scale because we only observed a higher carbohydrate concentration in species with larger genomes for four of the species pairs.
Root sprouters may have smaller genomes because of their frequent occurrence in dry and open habitats. Large-genome species with presumably large cells and vacuoles could accumulate more water-soluble carbohydrates at the end of the growing season to fuel their growth and perhaps protect vulnerable organs from freezing early in the next season.
有几条证据表明，植物地下器官的碳水化合物储存可能与基因组大小呈正相关，因为这两个植物特性都代表资源汇，并且可以影响细胞大小、细胞周期时间、水分利用效率和植物生长。然而，适应干扰的植物，如根蘖植物，可能是一个例外，因为它们的策略需要更高的碳水化合物储备来为生物质生产提供燃料，但需要较小的基因组以更快地完成细胞周期。
我们使用来自野外调查的数据来检验 172 种中欧草本植物的基因组大小与根蘖能力概率之间的关系。此外，我们进行了一个盆栽实验，涉及 19 种具有不同蘖能力的草本植物（9 个同属对加上 1 个种），并在生长季节结束时测量了根非结构性碳水化合物浓度和库。
在中欧植物群中，大基因组物种的根蘖能力概率较低，但这种模式较弱。在盆栽实验中，总非结构性和水溶性碳水化合物（主要是果聚糖）与基因组大小呈正相关且呈非线性关系，与蘖策略无关。单糖和二糖以及所有碳水化合物库的浓度与基因组大小无关，并且大基因组物种中不存在淀粉。在小系统发育尺度上，基因组大小和碳水化合物储存之间的联系不太明显，因为我们仅观察到在四个物种对中，大基因组物种的碳水化合物浓度更高。
根蘖植物的基因组可能较小，因为它们经常出现在干燥和开阔的栖息地。具有较大细胞和液泡的大基因组物种可能在生长季节结束时积累更多的水溶性碳水化合物，为其生长提供燃料，并可能在下一个季节早期保护脆弱的器官免受冻结。
