不同温度下PEG 模拟干旱对濒危植物狭叶坡垒种子萌发的影响

Hopea chinensis is distributed in China and its seeds are typical stubbornness. In orderto investigate the germination adaptability of seeds to temperature and moisture, we carried out anexperiment with three different constant temperature (15 , 20 and 25 ) controlled byartificial climate incubators, and six polyethylene glycol (PEG-6000) mass percentageconcentrations (0, 5%, 10%, 15%, 25% and 35%) were used 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 ofdrought stress applied, higher temperatures positively affected the germination rate, germinationenergy, germination index, radicle length, seeding length and vitality index of seeds, highertemperatures led to shorter germination delay and increased fluctuations in the germination period.(2) Drought stress had a significant impact on seed germination. Under identical temperatureconditions, increasing levels of drought stress resulted in reduced germination rate, germinationenergy, germination index, germination period, radicle length, seeding length and vitality index ofseeds. Moreover, higher levels of drought stress led to longer in germination delay of seeds. (3)The interaction between temperature and drought stress had a significant influenced on seedgermination. Under drought stress, seed germination exhibited different responses under differenttemperature conditions. Specifically, under conditions where a PEG-6000 concentration of 35%was applied as drought stress treatment, the germination rates at temperatures of 20 C and 25 Cwere significantly higher than those observed at 15 C (8.89% and 15.55% compared to lowerrates at 15 C). However, it was important to note that when subjected to both 35% PEG-6000 anda temperature of 15 C, the seeds no longer germinate. In summary, our results indicate that thesuitable temperatures for seed germination are identified as being around 20 C and 25 C. It isdetermined that the most favorable temperature for early seedling growth is 25 C. As the droughtstress intensifies, the inhibitory effect on seed germination become stronger. These findingssuggest that temperature plays a positive role in promoting seed germination, while drought stresscan significantly hinder this process. Additionally, moderate warming can help alleviate theinhibitory effect of drought stress on seed germination.