Abstract:

Hydrangea macrophylla is an important ornamental plant due to its rich flower colors and diverse forms. However, its application in Hangzhou is limited by the high temperature and humidity in summer. Present study systematically evaluated the heat and humidity tolerance of eight H. macrophylla cultivars by simulating a high-temperature and high-humidity environment using the artificial climate chambers, combined with morphological observation and physiological index measurements. The results showed that Miss Saori exhibited faster accumulation of soluble sugars and proline, higher soluble protein content, and greater increases in SOD and POD activities under high temperatures, enhancing its osmotic regulation and reactive oxygen species scavenging capacity. In contrast, Sweet Fantasy displayed lower MDA content, indicating milder membrane lipid peroxidation and a different stress resistance strategy. In conclusion, Miss Saori demonstrated stronger heat and humidity adaptability due to its superior enzyme activity enhancement. Present study not only provides H. macrophylla cultivars suitable for hot and humid climate in Hangzhou, but also provides a foundation for the cultivation management and genetic improvement of heat- and humidity- tolerant hydrangea varieties.

Key words: Hydrangea macrophylla, heat and humidity tolerance, introduction and cultivation, adaptability