When it comes to plants, we often think of them as passive, unable to move or respond quickly to external stimuli, and always seem to be in a state of resignation. But is that really the case?
In fact, plants are both proactive and smart, know how to use their strengths and know how to achieve win-win results. In the epic and magnificent evolutionary process, they have developed a series of amazing adaptation skills, such as what we are going to talk about today-some plants even heat up.
Plants also heat
up. In 1778, French biologist Lamarck discovered the strange phenomenon of flowers heating up for the first time while observing the flowering process of plants of the genus Araceae. This discovery has aroused the interest of botanists, and they have found more and more plants that produce heat in addition to the araceae plants. More than 200 years have passed, and now, people have observed remarkable phenotypes in the flowers, inflorescences or cones of more than 10 families of seed plants such as Annonaceae, Palmaceae, Aristolochiaceae, Cycadaceae, Ringflowers and Nymphaeaceae. Fever phenomenon.
How hot can it be? When
some plant species that are capable of strong heat production bloom, the highest temperature can even reach above 40°C, which is often 10-20°C higher than the surrounding temperature. For plants, which normally cannot regulate their body temperature, such heat is comparable to that of warm-blooded animals.
Araceae plants are leaders in the plant kingdom who are well versed in heat generation. Spotted southern star is a herbaceous plant native to southern Europe and northern Africa. The dark green and bright arrow-shaped leaves are delicate and lovely, making them a popular foliage plant.
The speckled southern star has the typical inflorescence of araceae plants, and the light green bracts are their iconic spathes. Spathes take good care of the spike-shaped inflorescences below them, sheltering them from wind and rain. Don’t underestimate this seemingly ordinary spadix, it is a veritable “heating rod”! The temperature of the warm spadix can reach over 30°C, which is much higher than the ambient temperature.
Like their distant relatives, cycads, cycads have no petals or buds, reproduce in the form of cones, and are usually pollinated by wind. However, sometimes they take a different path. Currently, about half of the known thermogenic plants are from the cycad family, and these plants are capable of heating male cones (microspore bulbs). Male cones consist of spirally arranged microsporophyll where pollen is abundant. While many angiosperms can only heat their flowers for a few hours to a few days, the “enthusiasm” of cycads is quite long-lasting, and they can heat male cones continuously for weeks. The temperature of the hot male cones at night can be 6°C higher than the ambient temperature, which is really amazing. Some cycad plants also have a rhythmic fever. They only heat up in the afternoon and evening when insects are active, and at the same time they release a sweet mint-like aroma and sap that contains sugar and amino acids.
Why it’s hot On the
one hand , warm flowers are good for plants and pollinators alike. The heat-generating plants in Araceae all have the ingenious design of “heating rods” to generate heat and spathe to keep warm. This structure and the heat generated can make the surrounding air flow rotate and become a vortex around the flowers. The airflow from all directions will eventually turn to the opening of the bud. In this way, the pollen produced by the male flower at the top of the flower can be blown into the female flower below. Plants themselves use air currents to facilitate pollination, even without insects to help pollinate them. So subtle, it’s amazing!
Human eyes, on the other hand, cannot see infrared light, but many insects can. Infrared radiation is an attractant for insects, and infrared light is a way for them to locate food. The hotter they are, the more intensely they emit infrared light. Therefore, we can imagine that in the eyes of insects, the warm flowers may be like the stars scattered in the forest. What a wonderful sight!
Raising the temperature can not only attract the attention of insects visually, but also greatly promote the fragrance of flowers, and “catch” insects in terms of smell. In the early stage of the opening of Daye Nansu, spathes loosened, and with the heat of the “heating rod”, the rich floral fragrance emanated from the cracks, which accelerated the positioning of insects. Fever can also promote pollen germination and pollen tube elongation, increasing the success rate of reproduction. This heating mechanism really kills two birds with one stone!
In nature, warmth itself is an immediate reward. With the warm scent of flowers, like an invisible invitation, many insects are invited to come to the flower party.
Warm flowers provide the best shelter for insects at night. Here, they dine, meet friends, stay and reproduce. Flowers are like “star hotels” for insects, and some insects will stay in the warm flower room for 24 hours. If the insects are kept, do you still have to worry about plant pollination? The mutual assistance between heat-producing plants and insects once again demonstrates the widespread mutual benefit and co-evolution in nature.
Where does the heat come from The answer to
this question lies in the mitochondria of plants, which are like a kind of energy factory. There, plants use carbohydrates or lipids and other energy storage substances to carry out a series of complex and sophisticated biochemical reactions to provide energy for plants. Substantially heating flowers is no easy task, and the mitochondrial “factory” prepares a special “production line” for this annual event. This “production line” is catalyzed by alternative oxidases, a unique oxidase pathway known as “anti-cyanide respiration”. Using this “energy production line”, it is possible to resist the inhibition of cyanide, prevent the formation of active oxygen, generate a large amount of heat, and realize the heating of flowers, etc.
There are still many unknown mysteries in the world of “warm-blooded” plants, which attract scientists to explore. However, there is a point of view that has been confirmed more and more, that is, the silent plants have created their own wisdom on the road of remarkable and fantastic evolution for hundreds of millions of years.
