13708

10.30848/PJB2026-1(15)

Physiological responses and heat tolerance evaluation of ten ground cover plant species under heat stress

Shuyue Yang, Airong Liu, Zhimin Zhao, Yuanbing Zhang, Shoucheng Huang and Kunkun Zhao

To explore the heat tolerance capabilities of 10 ground cover plant species, treatments using maximum temperatures of 25°C (control), 30°C, 35°C, and 40°C were performed in growth chambers. Compared with the control group (25°C), under heat stress (30°C, 35°C, and 40°C), the largest reductions in root activity and transpiration rates occurred in M. cordifolium (86.04%) and D. chinensis (61.77%), respectively. Except for P. lanceolata, V. hybrida, and D. chinensis, the reduction in water content for the other seven species (including C. roseus) was less than 5%. Under 40°C stress, photosynthesis-related indicators such as relative chlorophyll content, net photosynthetic rate, and stomatal conductance decreased by 1.39%-67.29%, 7.75%-52.46%, and 1.09%-57.28% respectively, while intercellular CO2 concentration increased by 12.08%-40.40% when compared to the control in the ten plant species. Under different temperature treatment conditions, superoxide dismutase (SOD) and peroxidase (POD) activities were highest in C. roseus, reaching 250.39 U/(g·min) and 3017.59 U/(g·min), respectively, while catalase (CAT) activity was highest in P. lanceolata at 152.73 U/(g·min). Malondialdehyde (MDA) content rose after increasing temperatures from 25°C to 35°C. However, the change trends of soluble protein, soluble sugar, and proline contents varied, ranging from -57.17% to 48.56%, -53.22% to 501.02%, and -47.66% to 227.34%, respectively. Principal component analysis showed that the first five principal components had a cumulative contribution rate of 83.162%. The membership function method combined with cluster analysis results allowed for the classification of these plants into three categories: strong heat tolerance (C. roseus, P. lanceolata, and T. fournieri, three species in total), moderate heat tolerance (V. hybrida, A. hispida, M. cordifolium, P. 'Cerveza'n Lime', and C. scutellarioides, five species in total), and weak heat tolerance (D. chinensis and T. cerinthoides 'Nanouk', two species in total). In summary, this study provides a physiological basis for selecting ground cover plant resources that could be used in areas with different temperatures

Published

2026 58 1