闽楠类异戊二烯释放对温度和短波光照的响应OACHSSCD

Isoprenoids(e.g.,isoprene(ISO)and monoterpenes(MTs)),constitute major fractions of biogenic volatile organic compounds(BVOCs).Under conditions of elevated temperature and intense light(particularly short-wave light),they undergo photochemical reactions with NOx,leading to Ozone(O3)formation.Additionally,these compounds are oxidized to form secondary organic aerosol(SOA).Consequently,isoprenoids indirectly influence atmospheric dynamics through their roles in O3 production and SOA generation.In this study,two-year-old P.Bournei seedings were selected as the research object,and three temperature gradients of 15/20℃,20/25℃,and 25/30℃(night/day)and three light quality treatments of white light(WL,full-spectrum),white light+blue light(BL),and white light+ultraviolet-B(UV-B)were set up.By determining the emission rates of isoprene and monoterpene,related enzyme activities and photosynthetic indexes under different treatments,the effects of temperature and short-wave light on emission of isoprene from P.Bournei were investigated.The results indicated that:(1)Under BL treatment,the emission rates of ISO and MTs from P bournei increased with rising temperature,with the maximum values of(47.326±1.081)pmol m-2 s-1 and(502.911±190.357)pmol m-2 s-1 at 25/30℃,respectively.Under UV-B treatment,both ISO and MTs emission rates generally increased with temperature,reaching their maxima at 20/25℃((44.684±6.703)pmol m-2 s-1 for ISO and(187.997±50.071)pmol m-2 s-1 for MTs).Compared with WL,the BL treatment reduced ISO emissions and the relative proportion of limonene,while the UV-B treatment increased the relative proportion of limonene.(2)Overall,the interactive effects of temperature and short-wavelength light significantly modulated MTs emissions:high temperature combined with UV-B inhibited emission of MTs,while low temperature combined with UV-B promoted the emission.Contrary to UV-B,the interaction effect of BL with lower temperature suppressed emission of MTs while enhanced the emission at higher temperature.Notably,no significantly interaction effect was observed on emission of ISO.(3)Temperature and light quality synergistically regulated photosynthetic metabolism and emission of BVOCs in P bournei.Temperature elevation increased net photosynthetic rate(Pn),isoprene synthase(IspS)and monoterpene synthase(MTPS)activities,reduced malondialdehyde(MDA)content,and altered MTs composition.Short-wave light enhanced IspS and MTPS activities while reducing chlorophyll content at both 20/25℃and 25/30℃.The findings of this study provides a theoretical basis for understanding the impact of global climate change(especially warming and enhanced short-wave radiation)on BVOC emissions,particularly from Lauraceae species,and the findings have significant implications for refining isoprenoid emission inventory estimations and predicting their feedback effects on atmospheric chemistry and climate dynamics.