Can seeds be rolled like this? With its own "motor" and "drill", it formulates a "priority germination" strategy...

We all know that it is difficult for plants to grow in the desert. In order to adapt to drought, plants have developed superb skills, and the mangniuer seedling is undoubtedly one of the best. In the deserts of western China, mangniuer seedlings are very important plants. Its seeds have their own "motor" and "drill" that can drill into the ground. When the environment is suitable, they will germinate and grow, turning the desert into an oasis. Therefore, mangniuer seedlings are called "desert strongmen."

Source: China Plant Image Database, photo by Zhu Renbin

1

The "ordinary" looking smilax china

Erodium is a genus of the family Erodium, which is a spring-flowering dwarf plant with about 74 species. The leaves of Erodium are opposite and deeply pinnate. The flowers are small and arranged in small umbrellas; the color is mostly purple-red, and each flower has 5 petals and 5 sepals, each sepal has a short awn.

E. cicutarium

Source: Wikipedia

It seems that there is nothing special about Erodium, but when the flowers fade and the fruit is born, it begins to "transform" gorgeously. After the flowers fade, a capsule with five sub-fruits is formed, about 4 cm long. The most obvious feature of the fruit is the "long beak" like the beak of a heron , and the genus name of Erodium means heron.

Source: China Plant Image Library, photo by Zhu Qiang

The plant of the genus Erodium mentioned at the beginning of the article, which grows in deserts and arid Gobi, is Erodium oxyrhinchum, which is mainly distributed in northern Xinjiang and Kashgar in China. Its fruit has a beak of 7 to 9 cm, which is feather-like when ripe and cracked . Erodium oxyrhinchum has a very short growth period. It will grow rapidly before the dry and hot summer climate arrives, using early spring rain or snowmelt water to complete its life cycle. Therefore, it belongs to a special type of plant - short-lived plants .

Fruit of the plant Geranium spicatum

Source: Xinjiang Botanical Society

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How do the seeds of the genus Ervatamia burrow into the ground?

In order to accomplish its mission, the seedling of the Chinese yam has evolved a unique seed dispersal mechanism - explosive dispersal . When the fruit matures, it will split into five sub-fruits, and the beaks of the sub-fruits will twist upward and curl in a spiral shape. This spiral and hairy appendage is called an awn, and the hairs on it are water-absorbent. When the fruit dries, the awn suddenly separates under the action of pressure, throwing the seeds out of the mother plant. This method of dispersal can spread the seeds to farther places to open up and occupy more territories.

How the fruit of the geranium opens

Source｜"The Magical World of Seeds" Photography/Li Lianyi

When the seeds fall to the ground, the changes in the wet and dry environment will cause the awns to straighten when wet and return to a spiral shape when dry . This change process will produce a rotational mechanical force, which will push the seeds into the ground, as if the seeds have a "drill" that buries itself in a wetter and safer environment, waiting for an opportunity to germinate.

Schematic diagram of the geranium spatholobi seedlings launching seeds and the seeds drilling into the ground

Source | "The mechanics of explosive dispersal and self-burial in the seeds of the filaree, Erodium cicutarium (Geraniaceae)"

Scientists have discovered through experiments that the awn undergoes a complex series of shape changes during the winding process. First a large bend appears, then a loose coil is formed, which slowly tightens as more coils extend toward the seed end. On sandy soils, the repeated movement of straightening and winding allows the seed head to move across the surface and randomly penetrate into gaps. After several changes in wet and dry conditions, some seeds are completely buried.

The soaked awns were placed on polymer clay and as the environment dried, the awns' intertwined shapes changed.

Source | "The mechanics of explosive dispersal and self-burial in the seeds of the filaree, Erodium cicutarium (Geraniaceae)"

The reason why the seeds of the spathiphyllum "burrow into the ground" is to increase their chances of germination and survival . Burying the seeds in the soil prevents them from being carried to adverse environments by the wind or being eaten by animals, which shows its ability to adapt to arid environments . The sharp-beaked spathiphyllum in the desert burrows its seeds deep into the soil, both to find a moist environment and to avoid damage caused by the huge temperature difference between day and night.

Geraniol

Source｜"The Magical World of Seeds" Photography/Yajidong

In order to cope with the harsh environment and expand the family power as much as possible, the sharp-beaked geranium seedlings have also developed a "germination priority" breeding strategy . If the seeds have not germinated for many years, they will lose their activity after the organic matter is consumed. Therefore, the old seeds will germinate and grow first, while the seeds in the young and middle-aged period will continue to wait and choose the right time to emerge, which is conducive to maintaining the stability of the seed bank. Scientific experiments have also confirmed this phenomenon. Under the same environment, fresh seeds are not easy to germinate, while the germination rate of old seeds is very high.

The seedlings of the Chinese yam plant may look weak, but they are very tenacious. In order to continue to multiply and grow, their seeds have evolved unique spreading abilities, showing us the most primitive instincts of life and the power of its vitality.