Abstract Flowers, from their initiation in the inflorescence meristem until their opening at anthesis, are particularly sensitive to subtle changes in environmental conditions. Short episodes of either cold or heat stress experienced during stamen development may lead to varying degrees of male sterility and can affect the ploidy of the gametes. In an attempt to understand the developmental origins of these and other phenotypes that are caused by harsh environmental conditions, an acute heat stress was simultaneously applied to all stages of anther development, and its consequences on pollen viability at anthesis and seed set were traced back to heat stress at specific developmental stages. We identified a critical stage during microsporogenesis that is highly sensitive to heat stress. The acute heat stress experienced during these stages completely blocked stamen and pollen development, likely mediated by its effects on both anther wall development and the formation of polyads in the germline. Interestingly, as we investigated heat shocks at earlier developmental stages, a gradual recovery of male fertility was observed, characterized by some abnormalities in locule development and by fusions of maturing pollen grains. Overall, our findings establish a developmental framework for the diverse effects of heat stress on stamen and pollen development, which is relevant to different fields of research. Acute heat stresses are expected to increase in frequency with global warming and might negatively affect plant fitness and crop yields in the short term by affecting male fertility and seed set. Moreover, the formation of polyads and the fusion of pollen grains offer insights into the developmental origins of evolutionary relevant processes, such as polyploidization, which might offer opportunities for environmental adaptations in the long term.

中文翻译：

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雄蕊发育过程中的急性热应激影响拟南芥 (L.) Heynh 的种系和孢子体谱系

摘要 花，从在花序分生组织开始到开花时开放，对环境条件的细微变化特别敏感。雄蕊发育期间经历的短期冷或热应激可能导致不同程度的雄性不育，并可能影响配子的倍性。为了了解由恶劣环境条件引起的这些和其他表型的发育起源，同时对花药发育的所有阶段施加了急性热应激，其对开花期和结实期花粉活力的影响可追溯到特定发育阶段的热应激。我们确定了对热应激高度敏感的小孢子形成过程中的关键阶段。在这些阶段经历的急性热应激完全阻止了雄蕊和花粉的发育，这可能是由其对花药壁发育和种系中多聚体形成的影响所介导的。有趣的是，当我们研究早期发育阶段的热休克时，观察到雄性生育力的逐渐恢复，其特征是细胞室发育的一些异常和成熟花粉粒的融合。总的来说，我们的研究结果为热应激对雄蕊和花粉发育的不同影响建立了一个发展框架，这与不同的研究领域相关。预计急性热应激的频率会随着全球变暖而增加，并可能在短期内通过影响雄性生育力和种子结实对植物健康和作物产量产生负面影响。而且，