Optimizing seed ball composition for enhanced germination, growth, and drought resistance in Robinia pseudoacacia

• Published in: Korean Journal of Agricultural Science, 52(2) Vol. 52; no. 2; pp. 81 - 93
• Main Authors: Yeonggeun Song, Youngin Hwang, Dongmin Choi, Hyeongkeun Kweon, Gijin Han, Kyeongcheol Lee
• Format: Journal Article
• Language: Korean
• Published: 농업과학연구소 01.06.2025
• Subjects: 농학; forest restoration; seed ball; chlorophyll a fluorescence; germination properties; Robinia pseudoacacia
• ISSN: 2466-2402; 2466-2410
• DOI: 10.7744/kjoas.520202

Widespread land degradation from climate change and human activities has disrupted forest ecosystems and hindered natural restoration. This study evaluated seed balls with varying soil compositions and bio-polymers for restoring vegetation in extreme environments. We examined their effects on the physical properties, germination, and early growth of Robinia pseudoacacia under drought stress. The results showed that seed ball hardness was the lowest in the 100% clay (C100) treatment (15.8 ± 3.4 mm), whereas, the 50% clay (C50) treatment and 30% clay (C30) treatment groups exhibited significantly higher hardness values of 24.8 ± 1.0 mm and 24.0 ± 1.3 mm, respectively, similar to those of the 0% clay (C0) treatment. Additionally, the C0 treatment group exhibited the lowest germination rate (9.4 - 18.8%), along with poor germination speed and uniformity, suggesting that excessive leaf mold content may harden the internal structure of seed balls, thereby inhibiting seed water uptake. Analysis of photosynthetic indicators revealed that maximum quantum yield of primary photochemistry (ΦPo) and performance index on absorption basis (PIABS) were highest in the C50 treatment group, whereas, they were 7 and 14% lower, respectively, in the C100 treatment group. In contrast, dissipated energy per reaction center (DIo/RC) was 27% higher in C100 compared to C50, indicating that higher clay content leads to reduced photosynthetic efficiency and increased energy dissipation. This suggests that excessive clay content may limit oxygen and water diffusion within the seed ball, thereby impairing photosynthetic mechanisms. A C50 ratio was optimal for germination, early growth, and maintaining seed ball hardness, making it the most suitable composition for restoration efforts in degraded areas.