The waboom is an iconic species with a wide distribution range, occurring from the Bokkeveld Escarpment to the Cape Peninsula in the Western Cape and eastwards to the Winterhoek Mountains in the Eastern Cape. Photo: Jan-Hendrik Keet.

Smoke as a Powerful Signal: A Revolutionary Breakthrough in Seed Treatment

In South Africa’s Cape Floristic Region, the stunning beauty of fynbos conceals a fragile natural balance that relies on fire. For many fynbos plants, including those in the protea, erica, and restio families, exposure to smoke is vital. Chemicals found in smoke aid in breaking seed dormancy, enabling these species to germinate and thrive after a fire.

Where There’s Fire, There’s Smoke

For many years, scientists believed that the intense heat from fires was the primary trigger for seed germination. This view was challenged during a controlled burn in 1989 at the Cape of Good Hope Nature Reserve. Hannes de Lange, a young researcher at the National Botanical Institute (now SANBI), was studying the effects of fire on the threatened fynbos species Audouinia capitata, commonly known as False Heath.

While the heat and flames were impressive, it was the pervasive smoke that captured his attention. De Lange discovered that although soil temperatures did rise during the fire, the increase was modest, comparable to that of a hot, sunny day. He found no clear link between these temperature changes and the rate at which the seeds sprouted. His suspicion that smoke played a crucial role was confirmed when he conducted further tests; exposing Audouinia capitata seeds to smoke significantly boosted their germination rates.

His groundbreaking findings, published in 1993, reshaped our understanding of how fynbos regenerates after fire.

Expanding the Research

Researchers at the University of KwaZulu-Natal embarked on an intriguing investigation into the properties of smoke, driven by a desire to understand its biological effects and the active compounds responsible for these benefits. Their efforts led to the identification of a significant compound known as karrikinolide (KAR1), a natural butenolide that plays a crucial role in stimulating seed germination.

The implications of this discovery are transformative for agricultural practices. Researchers demonstrated that karrikinolide not only facilitates enhanced germination rates in fynbos species—plants native to the Cape Floristic Region of South Africa—but also significantly boosts seedling vigor in staple crops such as rice, maize, and tomatoes. This finding suggests that KAR1 could be an essential tool for improving crop yields and supporting sustainable agriculture.

To translate this scientific insight into practical applications, the Kirstenbosch National Botanical Garden spearheaded the development of an innovative “instant smoke” solution. This process utilizes absorbent paper that has been treated with water infused with smoke, enabling farmers to apply this germination stimulant easily. This convenient method eliminates the need for open fires or specialized equipment, making it more accessible for growers in various agricultural settings. By harnessing the power of smoke through this effective treatment, farmers can enhance seed germination and promote healthier, more resilient crops.

A Lesson in Curiosity

The phenomenon of smoke-induced seed germination illustrates the importance of careful observation and the willingness to challenge established beliefs. Hannes de Lange’s insatiable curiosity, paired with his methodical approach to experimentation, led to a groundbreaking discovery that has significantly reshaped our understanding of fire ecology, plant conservation, and agricultural practices. His research showed that exposure to certain chemicals in smoke can trigger germination in specific plant seeds, even after long periods of dormancy.

This finding not only revolutionized strategies for restoring ecosystems affected by wildfires but also provided innovative solutions to enhance crop yields in agricultural settings. In today’s world, where information spreads rapidly, often before it can be verified, de Lange’s work serves as an important reminder of the essential role that rigorous scientific inquiry plays in promoting genuine progress and informed decision-making in both environmental and agricultural sectors.

Dr. Jan-Hendrik Keet, director and principal consultant at EcoFloristix, is a registered Professional Natural Scientist with a PhD in Botany from Stellenbosch University. He aims to enhance understanding of plant diversity and fynbos ecology.

Sourced from EcoFloristix by Dr Jan-Hendrik Keet