It is well known that in a moderately humid climate one corn plant consumes 200-250 liters of water during the growing season, and an adult cabbage plant requires 10 liters of water per day. It is good when that amount of water is available to the plant. And if it is not enough? And in general, have you thought about how plants fight drought?
Ephemera (cereals, poppies, crucifers) avoid drought, as if overtaking it - they develop very rapidly. In 5-6 weeks from the beginning of the wet season, they have time to bloom and give seeds. The soil dries up, drought sets in, and the seeds calmly await their time.
Ephemeral geophytes (tulips, sand sedge, etc., some authors call them ephemeroids), in addition to seeds, still have underground storage organs, protected from water loss by special covers.
Xerophytes are more cunning. Some of them (sclerophytes) develop a powerful root system up to several meters deep and reach moisture-containing layers or groundwater (when the Suez Canal was dug, the root of a camel thorn was found at a depth of 33 m!). Others, in various ways, sharply reduce the intensity of metabolism: the stems and leaves of many wormwoods are covered with hairs, which quickly die off and are filled with air (weak heat exchange and low heating of the leaves); some plants have shiny leaves and stems that reflect sunlight, or turn the leaves edge-to-edge towards the light; saxaul has no leaves at all (and does not give shade!), but its branches are green and photosynthesize.
Still others (poikiloxerophytes) dry out in the absence of moisture, but after wetting, they quickly restore the ability to vegetate (mosses, lichens). However, the most interesting is another group of xerophytes - succulents. In favorable periods of life, they accumulate water in themselves, and during a drought they use it extremely economically.
In some literary sources, xerophytes are divided into other groups, somewhere else they divide xerophytes and succulents, but all this has little effect on the logic of our narrative. The main thing is that xerophytes (from the Greek xeros - dry and fiton - plant) are plants of dry habitats and successfully cope with drought. Some of them can lose up to 60% of their water without death.
Let's dwell a little more on succulents. They do not in any way relate to botanical classification, and therefore you will not find them either in various Systems of the Plant Kingdom, or among taxonomic ranks and taxa. Just like many other "informal" associations, for example: trees, herbs, ephemera, ornamental crops, medicinal plants, etc. Figuratively speaking, succulentism is a way of life for xerophytic plants.
Succulents (from the Latin succulentus - juicy, fleshy) are a group of perennial xerophytic plants that are capable of accumulating water in a highly developed specialized tissue - an aquiferous parenchyma (up to 2-3 tons) and having a number of morphological and physiological adaptations for its economical use in a dry period. Such devices include the presence of a powerful cuticle (protective film), a special arrangement of leaves, often the absence of leaves, a special type of photosynthesis, the presence of thorns or thorns, a special shape of the stem, etc.
According to some estimates, arid (dry) zones occupy up to 35% of the earth's surface and encircle the entire planet. Therefore, succulents are widespread in America, and in Africa, and in Eurasia, and in Australia. Different authors count from 15 to 20 thousand species of succulents belonging to no less than 80 families! Note that not always all representatives of a family (and sometimes even a genus) growing in the same ecological conditions belong to the same type of xerophytes.
So, out of 331 genera of Euphorbiaceae (family Euphorbiaceae), only seven genera are recognized as succulent (although this is also a lot - from one and a half to two thousand species). In addition to them, the main "suppliers" of succulents are the families of cactus, mesembriantemic, fatty, orchid, bromeliad, asclepian and many others.
The whole "beauty" of the parenchyma (a special tissue for assimilation or release of moisture) is that water in one form or another makes up 95% of the contents of this tissue - these are real storage tanks! Water-storing tissue in plants can be located in the leaves, stem, and underground organs. Accordingly, leaf (aloe, agave, mezemba, haworthia), stem (cacti, adenium, stapelia) and root (milkweed, brachistelms) succulents are distinguished. It is important to note here that many species simultaneously have succulent leaves and a stem or a stem and a "root", etc. Therefore, the above division is very, very arbitrary …
"How does all this relate to our real life?" - you ask. It is very important.
First, the dry (especially in winter) air of our premises suits the inhabitants of deserts and semi-deserts - they do not need to be sprayed or any humidifiers should be placed nearby.
Secondly, you can easily leave your wards for a week or a month (and in winter - for months!) And leave with peace of mind even on a business trip, even on vacation, or even to a summer cottage. And for this you do not have to turn to a friend or a kind neighbor who will periodically take care of your plants - they will simply have a small dry period, to the presence of which in their life they are perfectly adapted.
Thirdly, photosynthesis in succulents proceeds in such a way that they release massive amounts of oxygen in the dark (when you are at home), and, unlike other plants, they emit very little carbon dioxide into the room per day.
Fourthly, rare watering will save your time 3 times, which is so expensive in our fast-paced age. Why three? Calculate for yourself: first of all, watering time is reduced by reducing the number of waterings. As one of the consequences, succulents grow more slowly, you need less time to form and prune (for those species that generally require it). And finally, due to a more rare transplant, since the "time of operation" of the soil mixture in the planting tank is lengthened. After all, it is no secret that the suitability of the substrate is often determined primarily by the quality of the water used for irrigation, as well as the correspondence of its quantity to the volume of the pot. As a result, some cacti and lithops (like the "best" succulents) with proper agricultural technology can feel quite normal and bloom profusely without transplanting for 5-7 years!
And yet … If you think that succulents do not like frequent watering, then this is a simple misconception. They love water, they love it! And during the growing season, in the presence of more or less optimal conditions for development (light, temperature, fresh air), you can water most succulent plants almost as often as other representatives of indoor flora. But succulents have learned well how to make do with the available amount of water (even if it is very little), for which they have worked out all their tricks. That is why drought is not a problem for them.