Biogenic volatile organic compound （BVOC） produced and emitted by plants exhibit high chemical reactivity in the atmosphere， exerting significant influence on atmospheric chemistry and climate change. They constitute important atmospheric trace gases. To elucidate the seasonal variation patterns and driving factors of BVOC emissions in alpine meadows， this study employed a dynamic headspace sampling system coupled with GC/MS technology for in situ monitoring in alpine meadows of northwestern Yunnan from July to October 2024， concurrently recording vegetation composition and environmental factors. we detected over 130 BVOCs belonging to 11 classes， including isoprene and monoterpenes. Total BVOC emission rates exhibited pronounced seasonal variation， peaking in July [（2485.51±847.08） μg·m^-2·h^-1] and reaching a minimum in October [（206.27±166.11） μg·m^-2·h^-1]. Emissions from July to August were dominated by isoprene （nearly 100%）， while emissions from September to October exhibited greater diversity， with notable increases in green leaf volatiles， sesquiterpenes， and aldehydes. Random forest analysis indicated isoprene as the key compound distinguishing monthly emission patterns. BVOC emissions were jointly influenced by temperature， light intensity， and vegetation structure： high temperatures and strong light promoted isoprene release， whereas low temperatures and plant senescence enhanced non-light-dependent BVOC emissions. Coverage of Carex muliensis was significantly positively correlated with isoprene emissions， while co-occurring species heterogeneity and flowering period variations enhanced BVOC emission diversity. These findings would aid in our understanding of BVOC-driven atmospheric processes and climatic feedbacks within the alpine meadows of northwestern Yunnan.

Biogenic volatile organic compounds  /  Alpine meadow ecosystems  /  Plant phenology  /  Seasonal variation