Effects of simulated drought by PEG-6000 on the germination of Hopea chinensis seeds under different temperature conditions

Hopea chinensis is distributed in China and its seeds are typically reclacitrant. In order to investigate the germination adaptability of seeds to temperature and moisture, we carried out an experiment with three different constant temperatures (15, 20, 25 ℃) controlled by artificial climate incubators, and used six polyethylene glycol (PEG-6000) concentrations (0%, 5%, 10%, 15%, 25% and 35%) to simulate drought stress. The germination characteristics of these seeds were carefully examined. The results were as follows: (1) Temperature exerted a significant influence on seed germination. Regardless of the level of drought stress applied, higher temperatures positively affected the germination percentage, germination energy, germination index, radicle length, sprout length and vitality index of seeds, higher temperatures led to shorter germination delay and increased fluctuations in the germination duration. (2) Drought stress had a significant impact on seed germination. Under identical temperature conditions,