Karrikinolide Maximises Seed Use Efficiency for Global Ecosystem Restoration and Nature Repair

Ecological restoration and nature repair combat ecosystem and land degradation, biodiversity loss and climate change. Yet seedling recruitment failure and perilously low plant survival (6-11%, often less) result in mass seed wastage. To understand its ability to improve seed use efficiency for restoration, the powerful germination stimulant karrikinolide or KAR1 (3-methyl-2H-furo [2,3-c]pyran-2-one) was evaluated for on-demand seed germination stimulation and plant recruitment in core restoration species. In line with global trends, our research demonstrated that KAR1 promoted on-demand germination in 82% of species across nine families. Our pioneering work also showed improved outcomes for deteriorating (aged) seeds and higher seedling recruitment, thereby enhancing seed use efficiency. The commercially available stimulant, gibberellic acid (GA3), provided no assistance beyond seed germination, suggesting KAR1 cannot be readily substituted. We recommend that KAR1 has the potential to meaningfully enhance seed use efficiency for nature restoration once challenges like cost and KAR1 delivery issues are overcome.