Plant-derived Smoke: A Sustainable Technique for Seed Enhancement

Smoke act as an important evolutionary factor involved in post fire germination cues. In South Africa, a study on the endangered fynbos species Audouinia capitata brought attention to the role smoke plays in promoting germination. Farmers of South Africa employ conventional method of exposing seeds to smoke as it provides protection against insects and pathogens. Additionally, this technique was shown to improve seedling vigor and germination in specific plant species. By directly exposing seeds to aerosol smoke, treating them with smoke water, or using dynamic compounds extracted from smoke at varying concentrations, the potential benefits of smoke in agriculture were realized. Among these, smoke water shows convenient and promising results. One well-known seed germination agent is butenolide (3-methyl-2H furo [2,3-c]pyran-2-one), which is produced from plant-derived smoke using bioactivity-guided fractionation. Following the initial isolation of KAR1, a whole new family of plant growth regulators, named ‘karrikins’ were isolated. Glyceronitrile or cyanohydrin is another compound isolated by using bioassay which stimulates germination in species which is insensitive to karrikins. Application of smoke had found to enhance germination by breaking dormancy, increasing seedling growth and mitigating abiotic stress conditions.