Zhejiang Asian Games | Plants also exercise series: Sensitivity causes "ADHD"

Diverse Asian civilizations have given birth to a variety of sports activities, including Kabaddi in South Asia, Sepak Takraw in Southeast Asia, Chinese martial arts, Japanese judo, and Taekwondo in the Korean Peninsula. These sports, which originated in different parts of Asia, have promoted mutual understanding and recognition among people, injecting vitality into Asian civilization. As a major sporting event that Asian people pay close attention to, the Asian Games has endowed people with precious spiritual wealth. From the first Asian Games in New Delhi, India in 1951 to the upcoming 19th Asian Games in Hangzhou, Asian sons and daughters have competed on the same field, fought hard, and demonstrated their unique strength and beauty with speed and skills, composing a higher, faster, and stronger Olympic spirit for the world.

On June 15, 2023, the Hangzhou Asian Games ushered in the important moment of the 100-day countdown. The atmosphere of the Asian Games in Hangzhou city is becoming more and more intense, and the 19th Asian Games is rapidly approaching us.

Life lies in movement, and every creature has its own unique form of movement. Competitive events such as archery, track and field, fencing, high jump, skiing, and swimming originate from the display of various survival skills of humans in nature. The running of cheetahs, the spreading of eagles, and the swimming of fish are the unrestrained speed and passion of animals. In nature, the movement of animals is commonplace, but have you ever seen the movement of plants?

Although plants do not have a nervous system, and will not jump or run, they seem to be quiet compared to animals. In fact, plants can also sense external stimuli and move. In order to better utilize external resources and adapt to environmental changes, plants can achieve various movements by changing the spatial position of their organs. This change in the position of organs is called "plant movement." As long as you observe carefully, you will find that the movement behavior of some plants is not only wonderful but also interesting. Let's learn some "cold knowledge" about "plants also move"!

Sensitivity causes ADHD

Mimosa has pale pink inflorescence and feathery leaves

Mimosa pudica

A perennial, loose, subshrubby herb of the Leguminosae family. It can grow up to 1 meter in height; the stem is cylindrical, branched, with scattered, downward-curved hooks and oblique spines. The pinnae and leaflets close and droop when touched; the pinnae are usually 2 pairs, arranged in a finger-like manner at the top of the petiole, and the leaflets are 10-20 pairs, linear and oblong. The head inflorescence is spherical with long peduncles; the flowers are small, light red, and shaped like pompoms. The pods are oblong, flat, with wavy margins and spines; the seeds are oval. The flowering period is from March to October; the fruiting period is from May to November.

Mimosa pods, with prickly surface

Mimosa pudica is native to tropical America and is now widely distributed in tropical regions of the world. It has the characteristics of rapid growth and strong adaptability. It generally grows in wilderness and bushes. It is often cultivated in the Yangtze River Basin of my country. Its flowers, leaves and pods are all highly ornamental and are used for potted ornamental, flower bed arrangement, ground cover greening, road slope protection and soil and water conservation. The whole plant of Mimosa pudica can also be used as medicine. It is cool in nature, astringent in taste, and has a calming effect. People often use fresh leaves to mash and apply externally to treat herpes zoster.

When the leaves of Mimosa pudica are touched, they will behave in a very "shy" way. Just a light touch will cause the pinnate leaflets to close quickly. If you use more force, the entire pinna will droop shyly, just like a shy girl. So why is Mimosa pudica so "shy"?

Moving bipinnate leaves

In fact, the structure of the stems and leaves of Mimosa pudica is very unique. There is an enlarged organ called "pulvinus" at the base of its petiole, the junction between the petiole and pinnae, and the base of the leaflets of the compound leaves. The primary pulvinus is at the junction of the stem and petiole. The leaflets are arranged in pairs to form pinnae. The secondary pulvinus is at the junction of the petiole and pinnae, and there is a tertiary pulvinus under each leaflet. There is a large vascular bundle in the center of the pulvinus. The vascular bundle is surrounded by thin-walled tissue with many intercellular spaces. Each thin-walled cell in the tissue has a large vacuole. Under the mediation of the osmotic pressure inside and outside the cell membrane, the water in the vacuole will squeeze the cell wall, so that the pulvinus maintains pressure, also called turgor pressure, so that the leaves and petioles can stand upright.

The pulvinus is the most sensitive to stimulation. Once the leaf is stimulated, the stimulation will immediately reach the tertiary pulvinus at the base of the leaflet, causing the two leaflets to close. If the stimulation is stronger, it will not only reach the secondary pulvinus at the junction of the petiole and the pinna, but will also quickly reach the primary pulvinus at the base of the petiole, causing the entire petiole to droop. But after a period of time, the cell sap gradually flows back to the pulvinus, and the leaf returns to its original appearance.

The morphology and structure of Mimosa pudica

Mimosa leaves

The touched Mimosa leaflets bend downwards in 1 to 2 seconds. This is due to the change in turgor pressure caused by the massive transport of positive and negative ions in the pulvinar motor cells induced by the electric waves.

This seismic movement of Mimosa pudica is a way of self-protection after being stimulated by the outside world. It is the result of long-term adaptation to the external environment during the process of system development. Mimosa pudica is native to tropical areas, where the climate is changeable. Whenever a storm hits, Mimosa pudica will quickly close its leaves and droop its petioles to resist the invasion of wind, rain and animals.

The "shy" personality of Mimosa pudica usually has some special functions. Scientists have found that Mimosa pudica can also predict earthquakes and catastrophic weather changes, and will produce unconventional growth activities in response to sudden unseasonal temperature differences, geomagnetic and geoelectric changes.

After talking about so many secrets of mimosa, do you really want to touch the leaves of mimosa with your own hands? But don't be careless. Mimosa contains a toxin called mimosa alkaloid, which can cause hair loss if you have long-term contact with it.

Mimosa pudica leaflets close after being touched

Do you know the principle of Mimosa exercise?