Acclimation to low but non‐freezing temperature represents an ecologically important process for Arabidopsis thaliana but also for many other plant species from temperate regions. Cold acclimation comprises and affects numerous molecular and physiological processes and the maintenance of sugar supply of sink tissue by photosynthetically active source tissue is essential for plant survival. Here, changes in vascular bundle (VB) structure at the leaf petiole were analysed together with sucrose exudation rates before and after cold acclimation. Six natural Arabidopsis accessions originating from southern and northern Europe were compared. Photosynthetic efficiency, that is, maximum and effective quantum yield of photosystem II, revealed a significant effect of environmental condition. Only for northern accessions was a highly significant negative correlation observed between leaf sucrose exudation rates, xylem, and petiole cross‐sectional areas. Furthermore, only for northern accessions was a significant increase of VB and leaf petiole cross‐sectional area observed during cold acclimation. In contrast, variance of cross‐sectional areas of cold acclimated southern accessions was strongly reduced compared to control plants, while mean areas remained similar under both conditions. In summary, these findings suggest that natural Arabidopsis accessions from northern Europe significantly adjust sink strength and leaf VB structure to maintain plant growth and photosynthesis under low temperature.

中文翻译：

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冷驯化对来自南欧和北欧的天然拟南芥种质的叶维管束结构和碳输出率有不同的影响。

适应低温但不结冰的温度对于拟南芥来说是一个具有重要生态意义的过程，对于温带地区的许多其他植物物种来说也是如此。冷驯化包括并影响许多分子和生理过程，并且光合活跃的源组织维持库组织的糖供应对于植物生存至关重要。在此，分析了冷驯化前后叶柄处维管束（VB）结构的变化以及蔗糖渗出率。对来自南欧和北欧的六种天然拟南芥品种进行了比较。光合效率，即光系统II的最大有效量子产率，揭示了环境条件的显着影响。仅对于北方种质，在叶蔗糖渗出率、木质部和叶柄横截面积之间观察到高度显着的负相关。此外，只有北方种质在冷驯化过程中观察到 VB 和叶柄横截面积显着增加。相反，与对照植物相比，冷驯化的南方种质的横截面积的方差大大减小，而在两种条件下平均面积保持相似。总之，这些研究结果表明，来自北欧的天然拟南芥种质显着调整库强度和叶片VB结构，以维持低温下植物的生长和光合作用。