Reproductive thermotolerance: from flower development to seed initiation

Global warming has increased the frequency and intensity of extreme heat events, threatening crop productivity and food security. Plant reproductive development is particularly vulnerable to high temperature, and even brief heat episodes can markedly reduce seed set. Heat stress disrupts multiple reproductive stages, including flowering, male and female gametophyte development, pollination, fertilization, and early seed development. Thus, reproductive thermotolerance requires coordinated regulation across developmental stages and tissue systems. In this review, we synthesize current knowledge of how high temperature affects plant reproduction from floral initiation to seed formation and summarize the underlying molecular mechanisms, including heat sensing, proteostasis, redox regulation, metabolism, and hormonal control. We further discuss strategies for improving reproductive heat resilience through breeding, biotechnology, and crop management. By framing reproductive thermotolerance as an integrated property of cellular and tissue homeostasis, this review provides a conceptual foundation for future mechanistic studies and for developing crops better adapted to a warming climate.