In general, you would think that almost all animals and plants, including humans, would find it very difficult to live without water. However, among the variety of plants on Earth, some species can survive without water for a long time. A representative example is the so-called resurrection moss, which lives in dry areas such as the Chihuahua Desert on the border between the United States and Mexico.

Scientific name for this rare plant

, which appears to die and rise again, is Selaginella lepidophylla, and belongs to ferns, not seed plants. However, as the name suggests, it does not die completely and then resurge, and in a dry environment without water, it turns dark brown and forms a ball-like mass as the stems come together. Then, when it is doused with water or exposed to a damp environment, it quickly absorbs moisture and restores its original shape and color as if it had been revived.

Emergence plants survive in a very dry environment with minimal metabolism, such as maintaining a dormant state. When it enters a dry, dormant state, the plant’s body appears to make special substances to prevent damage to tissues and cells.

Scientists studying Easter plants are trying to figure out how to find applications by elucidating the mechanism by which a plant can survive without water. If the principle of sunrise could be applied to other crops, it might help alleviate human food shortages by improving varieties that are highly resistant to drought or by making crops that can withstand rain even if they are dried out by almost no moisture loss.

Of course, the case of Easter plants is very special, but in fact, most plants already have their own countermeasures to prepare for a waterless environment. That is, it is the seeds produced by seed plants, because when the environment is not good, it can survive as a seed, and when the environment is favorable for the growth of plants, it can germinate. Occasionally, there are reports in foreign media that seeds hundreds of years old or more have suddenly germinated.

In general, it might be thought that animals, especially higher animals such as vertebrates, are more difficult to survive without water than plants, but there are exceptions to this. Moreover, it would be even more surprising if fish species that normally live in water could survive for months without water.

Lungfishes (; lungfishes) are the only fish that can survive by lying dormant in an environment without water, and they have a long, slender, eel-like body. It is often called one of the “living fossils” because it appeared in the Devonian period of the Paleozoic era, about 400 million years ago, and it still lives to this day. However, species diversity has declined significantly compared to the distant past, when it was widely flourishing, and today there are six species of lungfish in three genera. In general, fish breathe through gills in the water, but the lungfish, as its name suggests, has the ability to breathe air through its swim bladder.

Even more surprising is that the lungfish can survive for several months or more by entering a state of induced hibernation, not only by breathing air, but also being dehydrated without water. Not all species of lungfish are the same, but many species of lungfish do when the water in a river or lake dries up, burrow into the mud and secrete mucus from their bodies to form a sort of cocoon-like structure and survive there. Then, when it rains and the water becomes heavy, it cuts through the mud and returns to the water.

At first glance, it may seem like a hibernating animal with a minimal metabolism, but lungfish can live at least months or even years without water. If the principle that lungfish can survive in the mud through induced hibernation can be found and applied, it may be possible to conserve energy and food and extend the lives of people traveling long distances in the future, as often seen in science fiction movies.

Humans depend on water more than most other animals and plants, so it wouldn’t be easy to survive just a few days without drinking water. Since various grains and meats that are consumed by man also require a lot of water, when there is a severe drought, the prices of agricultural products go up and people in poor countries die of starvation.

Due to global warming and climate change, droughts and forest fires are more frequent than before and damage is increasing almost all over the world. Moreover, even groundwater, which has been used vitally, is showing signs of depletion in different places. . Some reports predict that in the next ten years, global water demand will exceed supply by 40%.

In addition, it is assumed that the “water flow” has changed due to the recent destruction of rainforests, etc., severe droughts and wildfires, and some experts consider this very important.

Originally, the word Refugia meant a place where animals and plants did not become extinct and survived because they were not affected much by climate change during the Ice Age, when cold struck most of the Earth in the past. Modern shelters, which can withstand drought and protect against water, are still found all over the world. For example, even when drought peaked in California a few years ago, redwoods are said to have been able to withstand drought in refugee territory, where the soil was sufficiently moist.

Water conservation will be very important not only for sustainable development but also for the survival of the human race. In addition to preserving rainforests and shelters, water is not an infinite resource that can be wasted carelessly, but rather a valuable “public good” that humanity should collect in moderation, and it should have an attitude towards the value of water.

(4625)