It is well known that in a moderately humid climate one corn plant spends 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 such an amount of water is available to the plant. And if she is missing? And in general, have you ever thought about how plants fight drought?
Ephemera (cereal, poppy, cruciferous) avoid drought, as if overtaking it - they have a very rapid development. For 5-6 weeks from the beginning of the wet season, they manage to bloom and give seeds. The soil dries up, drought sets in, and the seeds calmly wait in the wings.
In ephemeral geophytes (tulips, sand sedge, etc., some authors call them ephemeroids) besides seeds, there are still underground storage organs protected from water loss by special covers.
Xerophytes behave more cunningly. One of them (sclerophytes) develop a powerful root system up to several meters in depth and get to moisture-containing layers or groundwater (when digging the Suez Canal, the root of the camel spine was found at a depth of 33 m!). Others in different ways sharply reduce the metabolic rate: the stems and leaves of many wormwoods are covered with hairs that quickly die off and are filled with air (weak heat transfer and low leaf heatability); some plants have shiny leaves and stalks that reflect sunlight; or they turn the edges edge to light; saxaul has no leaves at all (and does not give a shadow!), but its branches are green and photosynthesize.
Third (poikiloxerophytes) in the absence of moisture they dry out, but after wetting they quickly restore their vegetative ability (mosses, lichens). However, another group of xerophytes - succulents - is most interesting. In favorable periods of life, they accumulate water in themselves, and during a drought they spend it extremely economically.
In some literary sources xerophytes divided into other groups, somewhere else xerophytes and succulents share, but all this has little effect on the logic of our narrative. The main thing is that xerophytes (from the Greek xeros - dry and phyton - plant) are plants of dry habitats and successfully cope with drought. Some of them at the same time can lose up to 60% of water without fatal outcome.
Let us dwell a little more on succulents. They do not belong to the botanical classification, and therefore neither in various Systems of the kingdom of Plants, nor among taxonomic ranks and taxa you will not find them. As well as many other “informal” associations, for example: trees, herbs, ephemera, ornamental crops, medicinal plants, etc. Figuratively speaking, succulentism is a way of life of xerophytic plants.
Succulents (from Latin succulentus - juicy, fleshy) - a group of species of perennial xerophytic plants capable of storing water in a highly developed specialized tissue - an aquiferous parenchyma (up to 2-3 tons) and having a number of morphological and physiological devices for its economical use in the 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 spikes, 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! We draw attention to the fact 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 (Euphorbiaceae family), only seven genera are recognized as succulent (though 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 cactus, mesembryanthem, Crassulaceae, Orchidaceae, Bromeliad, Asclepius, and many others.
The whole "charm" 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 storage tanks! Water-retaining tissue in plants can be located in the leaves, stem, and underground organs. Accordingly, leaf (aloe, agave, mezembi, haworthia), stem (cacti, adeniums, slipways) and root (euphorbia, brachistelma) succulents are distinguished. It is important to note here that in many species both succulent leaves and stem or stem and stem and root are both at the same time. Therefore, the above division is very, very arbitrary ...
“How does all this relate to our real life?” - you ask. Very significant.
FirstlyThe dry (especially in winter) air of our premises is quite suitable for the inhabitants of deserts and semi-deserts - they do not need to be sprayed or placed near any air humidifiers.
Secondlywithout any problems you can leave your wards for a week or a month (and in the winter for months too!) and with peace of mind leave for at least a business trip, at least on vacation, at least for a summer residence. And for this you do not have to turn to a friend or a good neighbor who will periodically look after your plants - for them there will simply be a small dry period, to the presence of which they are perfectly adapted to their life.
ThirdlyPhotosynthesis in succulents proceeds in such a way that they release oxygen massively in the dark (when you are at home), and unlike other plants, they emit very little carbon dioxide per day.
FourthA rare watering of 3 times will save your time, so expensive in our fast-moving century. Why at three? Count yourself: first of all, the time for watering is reduced by reducing the number of waterings. As one of the consequences - a slower growth of succulents, you need less time to form and trim (for those species for which this is generally required). And finally, due to a rarer transplant, since the “operating time” of the soil mixture in the planting tank is lengthened. 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 by the correspondence of its quantity to the volume of the pot. As a result, some cacti and lithops (as the "very-most" succulents) with competent 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, even as they love! And during the growing season, in the presence of more or less optimal conditions for development (lighting, temperature, fresh air), you can water most succulent plants almost as often as other representatives of indoor flora. But the succulents have learned well how to manage the amount of water available (even if there is very little of it), for which they have developed all their tricks. That's why drought is not a problem for them.