模拟增温对黄河三角洲湿地芦苇光合特性的影响OA北大核心CSCDCSTPCD

In this study,Phragmites australis,the dominant species in the coastal wetland of the Yellow River Delta,was used as the study object.An open-top chamber(OTC)was used to simulate warming,and a new-generation photosynthetic measuring instrument(LI-6800)was employed to systematically analyze the seasonal effects of elevated temperature on the photosynthetic physiological characteristics of P.australis.The results showed that the effects of warming on the photosynthetic physiology of P.australis exhibited obvious periodic changes.In the early growth stage(May and June),warming significantly increased the apparent quantum yield(AQY)and initial carboxylation efficiency(φ)by 25.0%and 71.4%,respectively,significantly enhanced the net photosynthetic rate(Pn),and increased the maximum net photosynthetic rate(Pnmax)by 21.3%.In the middle growth stage(July),warming significantly increased the maximum net photosynthetic rate by 77.3%,and water use efficiency(WUE)also increased significantly,indicating that P.australis exhibited adaptive adjustment to warming.In the late growth stage(August),the photosynthetic apparatus was under high-temperature stress,and light energy distribution became unbalanced.By September,warming delayed the functional decline to some extent(Pnmax increased by 4.5%),and photosynthetic limitation shifted to non-stomatal factors.This study revealed that the response of P.australis to warming is a dynamic process involving multi-parameter synergistic adaptation,and its long-term"blue carbon"function depends on the comprehensive balance between promotion and inhibition effects at different growth stages.