不同比值的红光和远红光对青绿苔草生长及生理响应的影响OA

Carex breviculmis is a perennial herbaceous plant in the Cyperaceae family,characterized by strong self-regeneration capacity,shade tolerance,drought tolerance,and barrenness tolerance,demon-strating considerable potential for landscape application in shaded environments.To elucidate the regula-tory role of different red/far-red ratios(R/FR)as shading signals on the physiological adaptation mecha-nisms of C.breviculmis,gradient R/FR treatments(1.2,0.6,0.4,and 0.2)were applied,with R/FR=1.2 serving as the control,and the responses of phenotype,photosynthetic characteristics,and antioxidant system were systematically analyzed over a 20-day treatment period.The results showed that under a light intensity of 200 μmol/(m²·s),R/FR=0.4 represented the optimal growth condition.After 10 days of treat-ment,plant height,leaf length,and leaf width under R/FR=0.4 increased significantly by 14.43%,25.43%,and 13.25%,respectively,compared with the control,and the net photosynthetic rate reached 6.48 µmol/(m2·s),indicating a pronounced photosynthetic advantage.Chlorophyll fluorescence analysis revealed that the maximum photochemical efficiency of PS Ⅱ(Fv/Fm)remained stable between 0.82 and 0.83,suggesting that PSⅡ maintained functional integrity and high light-energy utilization efficiency under low R/FR light conditions.Concurrently,biochemical analysis demonstrated that after 20 days of treat-ment at R/FR=0.4,malondialdehyde(MDA)content increased by 45.35%relative to day 0,and the activities of peroxidase(POD),catalase(CAT),and superoxide dismutase(SOD)increased by 142.36%,52.06%,and 778.30%,respectively;proline accumulation increased by 52.09%compared to day 0.These findings indicate that low R/FR induced an increase in stomatal aperture and simultaneously acti-vated the antioxidant enzyme and osmotic adjustment systems,which jointly mitigated oxidative stress imposed by the light quality.This study reveals the physiological adaptation strategies of C.breviculmis under low light quality conditions and provides a theoretical basis for its rational application in shaded green spaces.