Some plants generate heat to attract pollinators

Thermogenesis, the ability of plants to generate their own heat, is a remarkable survival tool that has evolved in certain plant species.

While commonly associated with animals, this process plays a crucial role in helping plants like cycads and select flowering varieties attract pollinators.

Plant heat attracts pollinators

By producing heat, these plants can volatilize their fragrances more effectively, dispersing chemical compounds that enhance their chances of attracting a wide variety of pollinators, including beetles, flies, and thrips.

This thermal boost not only makes the plants more appealing to insects but also plays a crucial role in the timing and success of pollination.

Additionally, this internal heat supports the development and growth of reproductive organs, such as flowers and pollen tubes, especially in cooler climates where warmth is scarce, giving thermogenic plants a distinct evolutionary advantage over non-thermogenic species.

Thermogenesis and plant evolution

Tracking heat generation in plants is challenging because thermogenesis cannot be directly preserved in the fossil record. This forces scientists to rely on indirect evidence, such as fossilized anatomical structures that may have supported heat production.

Without physical traces of heat itself, researchers must study plant morphology and compare ancient plants with modern thermogenic species to infer how this process may have operated in the past.

By examining anatomical similarities between ancient and present-day thermogenic plants, scientists can better understand how thermogenesis played a role in plant evolution.

Plant heat and evolutionary success

An intriguing study was recently conducted by a group of researchers at the Botanical Institute of Barcelona (IBB), in a collaborative effort with several esteemed institutions including the Complutense University of Madrid, the Geological and Mining Institute of Spain (IGME–CSIC), the Smithsonian Institution, the University of Barcelona, and the Royal Botanic Gardens of Sydney.

The experts diligently examined the characteristics of present-day thermogenic plants and compared them with fossil plant lineages.

The research led to a surprising conclusion. “Our findings suggest that thermogenesis in plants is an older phenomenon than previously thought,” said David Peris, a researcher at the IBB.

According to Peris, thermogenesis may have played a pivotal role in the evolutionary success of seed and flowering plants, as well as their pollinators, as far back as 200 million years ago.

An evolutionary edge

The presence of female structures maturing before male structures in thermogenic plants to prevent self-fertilization is a fascinating trait that is closely associated with early lines of divergence among flowering plants.

In fact, evidence of independent closing of stamens and carpels in floral chambers exists in fossil plants that could have trapped pollinating insects, hinting at their thermogenic past.

The researchers discovered that large reproductive structures, such as perianths or cones, could also indicate thermogenesis, thanks to their heat-retaining abilities.

These structures suggest that thermogenesis could have given certain Mesozoic plants a competitive edge over non-thermogenic equivalents more than 200 million years ago.

This heat-generating capacity, coupled with other attractive traits like flower color and fragrance emission, could have been instrumental in their reproductive success.

Diversification of plants and pollinators

“Thermogenesis in plants is not just a botanical curiosity,” said study co-author Iván Pérez-Lorenzo. He noted that this unique ability has strongly influenced the success of two diverse and populated groups: insects and flowering plants.

The findings open up exciting avenues for further inquiry into how such interactions may have influenced the diversification of plants and their pollinators throughout evolutionary history.

There is much more to learn from the world of plants, and this study has provided us with a fascinating glimpse into the world of thermogenesis.

Plants in a changing climate

The discovery of thermogenesis as a key factor in early plant survival offers exciting insights into the evolutionary journey of plants.

As scientists continue to investigate how heat generation has shaped plant-pollinator relationships over millions of years, new questions arise about its role in future evolutionary pathways.

Could thermogenesis have been a pivotal trait that allowed certain species to outcompete others in harsh environments?

Understanding this process may reveal how plants have adapted and diversified in response to changing climates and ecological pressures throughout history, and how they may continue to evolve in the face of future environmental shifts.

The study is published in the journal Nature Plants.

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