Potato (Solanum tuberosum L.) is an important food and vegetable crop worldwide. In recent years, the arid environment resulting from climate change has caused a sharp decline in potato yield. To clarify the effect of drought priming at the seedling stage on the tolerance of potato plants to drought stress during tuber expansion, we conducted a pot experiment to investigate the physiological response of the plants generated from seed potatoes of the variety ‘Favorita’ to varied water supply conditions: normal water supply at the seedling stage (control), normal water supply at the seedling stage and drought stress at the mid-tuber-expansion stage (non-primed), and drought priming at the seedling stage plus drought stress at the mid-tuber-expansion stage (primed). Drought priming resulted in an increase in the number of small vascular bundles in potato plants compared to non-primed plants. It also altered the shape and density of stomata, enhancing water use efficiency and reducing whole-plant transpiration. The primed plants maintained the basal stem cambium for a longer time under drought stress, which gained an extended differentiation ability to generate a greater number of small vascular bundles compared to non-primed plants. Drought priming increased the amount and rate of dry matter translocation, and so reduced the adverse effects on tubers of potato under drought stress. Therefore, drought priming at the seedling stage improved the photosynthetic performance and yield, and probably enhanced the drought tolerance of potato.

马铃薯（Solanum tuberosum L.）是世界范围内重要的粮食和蔬菜作物。近年来，气候变化造成的干旱环境导致马铃薯产量急剧下降。为了阐明苗期干旱引发对马铃薯植株块茎膨大过程中干旱胁迫耐受性的影响，我们进行了盆栽试验，研究了‘Favorita’种薯植株对不同水分的生理反应。供水条件：苗期正常供水（对照）、苗期正常供水+中薯膨大期干旱胁迫（未引发）、苗期干旱引发+苗期干旱胁迫块茎膨大中期（已引发）。与未引发的植物相比，干旱引发导致马铃薯植物中小维管束的数量增加。它还改变了气孔的形状和密度，提高了水分利用效率并减少了整个植物的蒸腾作用。与未引发的植物相比，引发的植物在干旱胁迫下保持基部茎形成层更长时间，从而获得了延长的分化能力，产生更多数量的小维管束。干旱引发增加了干物质转运的数量和速率，从而减少了干旱胁迫下对马铃薯块茎的不利影响。因此，苗期干旱启动提高了马铃薯的光合性能和产量，可能增强了马铃薯的耐旱性。