Seed‐Source Precipitation Drives Drought Acclimatization of Reaumuria songarica : Implications for Seed Germination and Seedling Growth in the HeHuang Valley

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ABSTRACT Reaumuria songarica is a key dominant species in the desert regions of northern China. The selection of appropriate seed source and the determination of optimal seed harvesting times are critical for the development and utilization of its germplasm resources. In this study, nine R. songarica habitats with varying precipitation levels were identified in the HeHuang Valley. We determined the optimal seed harvesting period and evaluated seed traits, germination characteristics, and initial seedling growth at this optimal period harvest time. The results indicated that the optimal harvesting window for R. songarica seeds is between 60 and 100 days after flowering, depending on the precipitation of the seed source area. Species origin accounted for the largest variation in seed germination characteristics and seedling growth, with the highest coefficient of variation observed in the vitality index (28.44%) and the lowest in seed viability (3.78%). In the standard germination test, seed germination was primarily influenced by 1000‐seed weight and seed viability, while seedling growth was mainly affected by seed electrical conductivity. Seed drought germination resistance was most influenced by seed biofilm integrity and seed size. In conclusion, high‐quality, drought‐tolerant R. songarica germplasm can be obtained by selecting drought‐prone seed source areas in the HeHuang Valley and harvesting seeds between 90 and 100 days after flowering. These findings underscore the critical role of precipitation at the seed source in shaping seed and seedling traits, providing valuable guidance for the future development and utilization of R. songarica germplasm resources.

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