Data_Stress-mediated variation in growth and adaptive ploidy plasticity in an invasive grass

Localized increase in cellular ploidy—endopolyploidy— is a common phenomenon during development and is also a primary response to stressful environments for many plant and animal species. Yet the evolvability of endopolyploidy as a plant stress response and its ecological consequences remain important open questions. Here we use 23 populations of a globally invasive grass collected from agricultural and non-agricultural habitat types to test for intraspecific variation in endopolyploidy levels, and how it corresponds with plant performance in response to three major stresses (herbicide exposure, simulated herbivory/mowing, and competition). Overall, plants significantly increased cell ploidy in response to herbicides and simulated herbivory/mowing, but not to competition. We found distinct phenotypic and endopolyploidy responses between plants from agricultural and non-agricultural habitats following herbicide application—suggesting that genotypic variation in ploidy plasticity may be adaptive, involved in compensatory growth responses, and influence plant-plant interactions. Populations with lower levels of endopolyploidy performed better in the field under intense competition with weeds, whereas populations with more endopolyploidy performed better under competition with corn. Together, our results shed light on an understudied adaptive response which plays an important role in how plants interact with each other, mitigate stress, and adapt to different environments.

细胞倍性的局部升高——即内多倍化（endopolyploidy）——是动植物发育过程中的常见现象，同时也是诸多物种应对胁迫环境的主要响应方式。然而，内多倍化作为植物胁迫响应的演化潜力及其生态后果，仍是亟待解答的重要科学问题。本研究采集了源自农田与非农田生境的23个全球入侵性禾草种群，用以检测内多倍化水平的种内变异，以及该变异与植物在三种主要胁迫（除草剂暴露、模拟植食/刈割、种间竞争）下的表现之间的关联。整体而言，植物在除草剂暴露与模拟植食/刈割胁迫下显著提升了细胞倍性，但在种间竞争胁迫下未出现该变化。我们发现，经除草剂处理后，源自农田与非农田生境的植物在表型与内多倍化响应上存在显著差异——这表明倍性可塑性的基因型变异可能具有适应性，参与补偿性生长响应，并可影响植物间的互作。内多倍化水平较低的种群在田间与杂草的激烈竞争中表现更优，而内多倍化水平较高的种群则在与玉米的竞争中表现更佳。综上，本研究结果揭示了一个尚未被充分研究的适应性响应机制，该机制在植物互作、胁迫缓解以及环境适应过程中发挥着关键作用。