Oxygen uptake rates have contrasting responses to temperature in the root meristem and elongation zone
Oxygen uptake rates have contrasting responses to temperature in the root meristem and elongation zone
复制标题
根分生组织和伸长区的吸氧率对温度有不同的反应
DOI：
10.1111/ppl.13682
复制
发表时间：
2022
影响因子：
6.4
通讯作者：
Baskin, Tobias I.
中科院分区：
文献类型：
--
作者：
Zimmermann, Maura J.;Bose, Jayakumar;Kramer, Eric M.;Atkin, Owen K.;Tyerman, Stephen D.;Baskin, Tobias I.
拟南芥的根在15℃或25℃下生长，以相同的速率产生细胞，并具有相同长度的生长带。为了确定这种恒定是否与能量学有关，我们通过振动氧选择电极测量了氧摄取量。同时，对延伸率的空间分布进行了运动学测量，划定了分生组织和延伸区。所有的幼苗都在给定的温度(15或25摄氏度)下萌发、生长和测量。哥伦比亚大学与细胞生产率在15至25摄氏度之间大致翻了一番的品系进行了比较：Landsberg和哥伦比亚大学的两个突变体er-105和ahk3-3。根据记者的荧光，在所有基因型和温度下，根冠上任何位置的氧气吸收速率都最高，那里的线粒体密度最大。吸收速率通过分生组织下降到延伸区内的平台期。对于一个区域的综合耗氧速率，分生组织的稳态Q10值在0.7到2.1之间；相比之下，伸长区域的Q10值在2.6到3.3之间，这意味着该区域施加了更大的呼吸需求。这些结果突出了根冠的大量能量消耗，可能有助于维持干细胞的低氧，并表明快速伸长在代谢上比细胞分裂的成本更高。
Growing at either 15 or 25°C, roots ofArabidopsis thaliana, Columbia accession, produce cells at the same rate and have growth zones of the same length. To determine whether this constancy is related to energetics, we measured oxygen uptake by means of a vibrating oxygen‐selective electrode. Concomitantly, the spatial distribution of elongation was measured kinematically, delineating meristem and elongation zone. All seedlings were germinated, grown, and measured at a given temperature (15 or 25°C). Columbia was compared to lines where cell production rate roughly doubles between 15 and 25°C: Landsberg and two Columbia mutants,er‐105andahk3‐3. For all genotypes and temperatures, oxygen uptake rate at any position was highest at the root cap, where mitochondrial density was maximal, based on the fluorescence of a reporter. Uptake rate declined through the meristem to plateau within the elongation zone. For oxygen uptake rate integrated over a zone, the meristem had steady‐stateQ10values ranging from 0.7 to 2.1; by contrast, the elongation zone had values ranging from 2.6 to 3.3, implying that this zone exerts a greater respiratory demand. These results highlight a substantial energy consumption by the root cap, perhaps helpful for maintaining hypoxia in stem cells, and suggest that rapid elongation is metabolically more costly than is cell division.