Clonal Integration Promotes the Photosynthesis of Clonal Plant Under Heterogeneous Pb and/or Pyrene Stress

Abstract

Clonal plants can support the growth of their ramets in heterogeneous environments through clonal integration between the ramets. However, the role of clonal integration in modulating ramet photosynthesis under toxic stress, especially combined stress, is unclear. This study examines the impact of clonal integration on Zoysia japonica under three heterogeneous stresses (Pb, pyrene, and Pb+Pyrene) with two stolon connection conditions (connected and disconnected). Our results show that clonal integration significantly enhances PN, gs, Ci, E, and CE while reducing WUE. It also improves ΦPSII, Fv′/Fm′, Fv/Fm, Fv/F0, and qP while reducing NPQ. Clonal integration lowers MDA levels, increases SOD activity, and mitigates the decline in CAT and POD activity, resulting in increased biomass under stress. Furthermore, we observed that the synergistic effects of the Pb+Pyrene mixture negatively impacted the adaptability of clonal integration. Our study underscores the role of clonal integration in maintaining photosynthesis and supporting the success of clonal plants in toxic environments.