Iranian Medicinal Plants Society Journal of Medicinal plants and By-products 2322-1399 15 3 2026 05 01 Germination and Recovery of the Seed of Three ‌Nepeta L. species under Drought and Temperature Stresses 327 333 135276 10.22034/jmpb.2026.370146.2016 EN Parvin Salehi Shanjani Research Institute of Forests and Rangelands, Agricultural Research Education and extension Organization (AREEO), Tehran, Iran Leila Rasoulzadeh Research Institute of Forests and Rangelands, Agricultural Research Education and extension Organization (AREEO), Tehran, Iran Bahareh Afsharnejad Research Institute of Forests and Rangelands, Agricultural Research Education and extension Organization (AREEO), Tehran, Iran Journal Article 2025 07 20 Propagation through seeds is an effective method for renewing plant populations and increasing their genetic diversity, but the process of seed germination is complex and relatively difficult due to the limitations of environmental conditions. Wild plants that reproduce through seed may be affected by changes in humidity and temperature. The present study aimed to investigate the ecological adaptation strategies of seed germination of three species of ‌Nepeta haussknechtii, N. pogonosperma and N. glomerulosa subsp. staffina under different hydrothermal conditions. Controlled experiments were conducted to investigate the germination performance of ‌Nepeta seeds at different temperatures (10 °C, 15 °C, 20 °C, 25 °C, 30 °C, and 35 °C) and simulated drought stress conditions using polyethylene glycol 6000 (PEG) concentrations (0, -0.3, -0.6, -0.9, and -1.2 MPa); since no germination was observed at 40°C and -1.5 MPa, the results of these values were excluded from the experiment. After 14 days, fresh ungerminated seeds from the hydrothermal treatments were transferred to distilled water (under 25°C conditions) to study the recovery of germination, which was also recorded at 2-day intervals for 14 days. The results showed that temperature, drought stress, and their interaction significantly affected the germination percentage and germination rate of seeds (p<0.01). The germination percentage and germination rate of the seed were significantly higher at 25°C compared to other temperatures (p<0.01). Drought stress inhibition on seed germination was increased by PEG-6000 solution concentrations. The percentage of ungerminated seeds that recovered after transfer to distilled water varied with temperature. Rehydration germination results showed that extremely high temperatures and drought stress conditions prevented seed germination of Nepeta seeds by destroying the seed structure. The seeds that fail to germinate under drought stress recover germination more quickly at lower temperatures than at higher temperatures. These results may indicate that a small percentage of Nepeta seeds can survive drought conditions and extreme higher temperatures will be able to germinate after drought levels are reduced by rainfall. Therefore, the predicted warmer and drier climate will inhibit Nepeta seed germination, indicating that temperature changes appear to play an important role in the recovery of Nepeta seed germination from drought stress.

https://jmpb.areeo.ac.ir/article_135276_3e6cdf92ece1d5b041daa83c6a63c97f.pdf