Characteristics of epiphytic plants and examples of indoor flowers. Biological characteristics of epiphytic plants Epiphytic plants receive the necessary nutrients from
Epiphytes can be divided into three groups: nesting, reservoir (tank) and bracket (pocket).
Nesting epiphytes include some types of ferns, aroids, and orchids. Falling leaves and waste products of animals and birds are retained by the roots, and the rosette of leaves ends up in a kind of “nest” that retains moisture well and provides nutrition.
Reservoir epiphytes are represented mainly by bromeliads. The leaves form a rosette or reservoir in which water accumulates. Under natural growing conditions, some species have reservoirs containing up to 5 liters of water. The reservoir can be common to the entire plant or each leaf forms its own “cistern”, which is associated with the peculiarities of the location and structure of the leaves.
Clamp or pocket epiphytes are distinguished by an asymmetrical rosette. All or part of the leaves adjacent to the support (tree trunk) form pockets or funnels, which in cross section have the shape of a bracket. Such leaves are formed, for example, in ferns of the genus Antler or Platycerium at a young age.
The roots of epiphytes are covered with a special covering tissue - velamen, which actively absorbs moisture from the air.
In addition to true epiphytes, there are semi-epiphytes, which lose contact with the soil for a short period of time. This can occur at a young age, when the seeds germinate, like true epiphytes, on trees, in sub-
stratum, consisting of rotten foliage, waste products of animals, etc., and only subsequently long adventitious roots reach the ground and are fixed in it. In other species, the seeds germinate on the ground, then rise up the support and may lose contact with the soil for a while, but then it is restored. In some hemiepiphytes, during germination, a special structure is formed - an eocaulum, resembling an elongated stem and colored green. The eocaul provides nutrition to the seedling until it transitions to the independent process of photosynthesis.
In interiors, epiphytes are most often grown in hanging baskets or flower pots. Orchids look especially impressive in baskets made of wooden sticks (round or square in cross-section). They are distinguished by a rather powerful root system, which requires a large volume.
Of course, in room conditions Epiphytes are most often grown as ordinary terrestrial plants in pots, but they look much more spectacular in hanging baskets, block culture and, of course, on “epiphytic trees”.
Baskets for epiphytes are “equipped” as follows: the bottom is lined with a fine mosquito net, sphagnum high peat, fern roots, fallen birch leaves are placed on it, they can be replaced with leaf soil, pine bark (3-5 cm high). The base of the basket is made of wire, wooden blocks of round or rectangular cross-section. Such baskets are suitable for orchids that have a fairly large root system, and therefore they do not do well on epiphytic trees.
Plants are planted so that the base of the stem is 1 - 2 cm below the edge of the basket. When transplanting, the plants are carefully removed from the basket, its contents are shaken out and sorted, updating the necessary components.
Epiphytes in block crops look no less impressive. This is a great technique for vertical gardening. Almost all types of epiphytes, even orchids, can be grown in blocks, especially considering that they aerial roots sensitive to lack of oxygen.
There are two known types of blocks: open and closed. Open - plants are strengthened with wire on large pieces of substrate (fern rhizomes, bark, pressed sphagnum). Depending on the size, one block can accommodate from 1-2 to 4-5 plants. If you plan to hang the block on the wall, it is first attached to a solid base: a small board, a plexiglass plate, a ceramic plate, etc. If the substrate is too loose, it is placed in a fine mesh.
In closed blocks this problem is not significant. Large pieces of larch, oak, birch, and pine bark are fastened with wire so that it looks like a pot. Of course, the bark of a cork tree or Amur velvet is best suited for this purpose, but the availability of these types is a big problem. The block is filled with loose substrate, the roots of the epiphytes, passing through it, are attached to the walls of the bark. It is quite possible to place blocks on an epiphytic tree. IN last years Abroad they produce ready-made blocks with holes into which young plant specimens can be planted.
But the biggest impression is made by the “epiphytic tree”. However, it should be noted that this is also the most labor-intensive option for placing epiphytes.
For an epiphytic tree, choose a snag of an original shape. The most suitable species for this is white acacia (Robinia pseudoacacia). The trunk has an interesting texture, the wood is quite soft, the roots of epiphytes easily strengthen in it, and it is quite resistant to rotting. You can also use pear, apple, and grape trunks. The more bizarre the shape of the selected driftwood, the more spectacular the epiphytic tree looks.
The driftwood is strengthened in a decorative flowerpot. A substrate typical for epiphytes is placed on the forks or on the trunk. Sometimes a depression is made in it, in which the plants are secured with thin wire. Open block crops can also be attached to the trunk. You should not turn an epiphytic tree into something like a Christmas tree or a May pole. In this case, the well-known principle “less is more” is more appropriate. The most spectacular type is best placed in the lower (1/3 of the height) part of the driftwood; higher up in the forks it’s good to “attach” lighter and smaller plants; below the accent type, large, “heavy” rosettes of ferns or Wenland’s philodendron look great. The snag can be entwined with a vine, or Tillandsia osniformes or tiny ficus can be hung from the ends of the branches. Last time. Some companies offer fairly unpretentious epiphytic miniature orchids that will serve as a decorative addition to any composition: Kingidium delisiosum and Neofinetia falcate.
Caring for plants comes down to daily spraying with warm, almost hot in the cold season, water. Once a month, the substrate is moistened with a solution of urea (1-1.5 g/l) and microfertilizers.
When transplanting, epiphytes are watered abundantly within 1-2 days, then the block or individual plants are removed and the substrate is replaced with fresh one. Overgrown roots are trimmed, and large specimens are divided into 2-3 plants. Fracture sites are being treated charcoal.
However, not everyone can create an “epiphytic tree,” so you can use “epiphytic shoots” - wrap a small branched snag with moss, secure it with wire or strong threads and plant small plants.
“Epiphytic rock” looks no less impressive - to create it you will need an unusually shaped piece of soft stone - tuff, limestone or pumice. Make small depressions in it, fill them with a suitable substrate and plant small specimens of plants.
Since the trees in tropical forests are quite tall, epiphytes that choose habitats at different heights differ in their needs. The most shade-tolerant and moisture-loving ones live close to the soil; those who prefer more light and not such a high level of air humidity settle in the crowns of trees; this is the most numerous group. And the branches at the very top were chosen by dry-bearing epiphytes. They chose the most difficult conditions: sharp fluctuations in daily temperature, lack of moisture, sharp gusts of wind, increased insolation, and a substrate not too rich in humus. Species settling in the crown and on the lower forks of the trunk receive nutrients c- rainwater, which washes away organic matter from the branches located above, washes away debris - waste products of animals and birds.
Epiphytes can be divided into three groups: nesting, reservoir (tank) and bracket (pocket).
Nesting epiphytes include some types of ferns, aroids, and orchids. Falling leaves and waste products of animals and birds are retained by the roots, and the rosette of leaves ends up in a kind of “nest” that retains moisture well and provides nutrition. 
Reservoir epiphytes are represented mainly by bromeliads. The leaves form a rosette or reservoir in which water accumulates. Under natural growing conditions, some species have reservoirs containing up to 5 liters of water. The reservoir can be common to the entire plant or each leaf forms its own “cistern”, which is associated with the peculiarities of the location and structure of the leaves.
Clamp or pocket epiphytes are distinguished by an asymmetrical rosette. All or part of the leaves adjacent to the support (tree trunk) form pockets or funnels, which in cross section have the shape of a bracket. Such leaves are formed, for example, in ferns of the genus Antler or Platycerium at a young age.
The roots of epiphytes are covered with a special covering tissue - velamen, which actively absorbs moisture from the air.
In interiors, epiphytes are most often grown in hanging baskets or flower pots. Orchids look especially impressive in baskets made of wooden sticks (round or square in cross-section). They are distinguished by a rather powerful root system, which requires a large volume. 
Of course, in indoor conditions, epiphytes are most often grown as ordinary terrestrial plants in pots, but they look much more impressive in hanging baskets, block culture and, of course, on “epiphytic trees”. 
Baskets for epiphytes are “equipped” as follows: the bottom is lined with a fine mosquito net, sphagnum high peat, fern roots, fallen birch leaves are placed on it, they can be replaced with leaf soil, pine bark (3-5 cm high). The base of the basket is made of wire, wooden blocks of round or rectangular cross-section. Such baskets are suitable for orchids that have a fairly large root system, and therefore they do not do well on epiphytic trees.
Plants are planted so that the base of the stem is 1 - 2 cm below the edge of the basket. When transplanting, the plants are carefully removed from the basket, its contents are shaken out and sorted, updating the necessary components.
Epiphytes in block crops look no less impressive. This is a great technique for vertical gardening. Almost all types of epiphytes can be grown in blocks, even orchids, especially considering that their aerial roots are sensitive to lack of oxygen. 
There are two known types of blocks: open and closed. Open - plants are strengthened with wire on large pieces of substrate (fern rhizomes, bark, pressed sphagnum). Depending on the size, one block can accommodate from 1-2 to 4-5 plants. If you plan to hang the block on the wall, it is first attached to a solid base: a small board, a plexiglass plate, a ceramic plate, etc. If the substrate is too loose, it is placed in a fine mesh. 
In closed blocks this problem is not significant. Large pieces of larch, oak, birch, and pine bark are fastened with wire so that it looks like a pot. Of course, the bark of a cork tree or Amur velvet is best suited for this purpose, but the availability of these types is a big problem. The block is filled with loose substrate, the roots of the epiphytes, passing through it, are attached to the walls of the bark. It is quite possible to place blocks on an epiphytic tree. In recent years, ready-made blocks with holes into which young plant specimens can be planted have been produced abroad.
But the biggest impression is made by the “epiphytic tree”. However, it should be noted that this is also the most labor-intensive option for placing epiphytes.
For an epiphytic tree, choose a snag of an original shape. The most suitable species for this is white acacia (Robinia pseudoacacia). The trunk has an interesting texture, the wood is quite soft, the roots of epiphytes easily strengthen in it, and it is quite resistant to rotting. You can also use pear, apple, and grape trunks. The more bizarre the shape of the selected driftwood, the more spectacular the epiphytic tree looks. 
The driftwood is strengthened in a decorative flowerpot. A substrate typical for epiphytes is placed on the forks or on the trunk. Sometimes a depression is made in it, in which the plants are secured with thin wire. Open block crops can also be attached to the trunk. You should not turn an epiphytic tree into something like a Christmas tree or a May pole. In this case, the well-known principle “less is more” is more appropriate. The most spectacular type is best placed in the lower (1/3 of the height) part of the driftwood; higher up in the forks it’s good to “attach” lighter and smaller plants; below the accent type, large, “heavy” rosettes of ferns or Wenland’s philodendron look great. The snag can be entwined with a vine, or Tillandsia osniformes or tiny ficus can be hung from the ends of the branches. Last time. Some companies offer fairly unpretentious epiphytic miniature orchids that will serve as a decorative addition to any composition: Kingidium delisiosum and Neofinetia falcate. 
Caring for plants comes down to daily spraying with warm, almost hot in the cold season, water. Once a month, the substrate is moistened with a urea solution (1-1.5 g/l) and microfertilizers.
When transplanting, epiphytes are watered abundantly within 1-2 days, then the block or individual plants are removed and the substrate is replaced with a fresh one. Overgrown roots are trimmed, and large specimens are divided into 2-3 plants. The fracture sites are treated with charcoal.
However, not everyone can create an “epiphytic tree”, so you can use “epiphytic shoots” - wrap a small branched snag with moss, secure it with wire or strong threads and plant small plants. 
“Epiphytic rock” looks no less impressive - to create it you will need an unusually shaped piece of soft stone - tuff, limestone or pumice. Make small depressions in it, fill them with a suitable substrate and plant small specimens of plants.
Tropical forest... Huge trees on all sides. From below, their smooth trunks seem like columns resting on a solid green arch. It is always twilight here - only 1% of sunlight passes through the dense foliage.
Excuse me, but where are the lush tropical thickets? Only small ferns and mosses cover the lower part of the tree trunks, and even with the last of their strength, stunted, pale young trees stretch upward, towards the light. There is no other vegetation in the lower layer of the tropical rainforest.
On the edges, clearings and along the banks of forest rivers, the vegetation is incomparably richer. This is where the jungle is intertwined with vines and almost impassable for humans, in which birds chirp, colorful butterflies flutter, and bright flowers bloom. It seems that all the power of tropical nature is concentrated here, but in fact this impression is deceptive. And the rainforest is full of life. Just look for it not in the lower tier - it is concentrated higher - at a height of 20-30 m above the ground. There, in the crowns of forest giants, according to some scientists, up to 40% of all species of animals and plants known on the planet live. Imagine: a continuous green canopy with its own animal and plant life, hovering above the surface of the planet and resting on it only with support trunks. An entire populated continent raised to dizzying heights!
This world suspended above the earth is unusual. Here live animals that, once on the ground, cannot take a single step. There live birds whose chicks, having not yet learned to fly, already move freely from branch to branch, clinging with claws located on the wings. Frogs there lay their eggs in small ponds formed in the axils of the leaves, insects look like green leaves, and fish sometimes live in the hollows of trees...
Epiphytic plants provide shelter and food for all these strange animals. They themselves are also unusual in many ways, but before we get to know them better, let's find out what made the plants, which, it would seem, were destined by nature itself to grow on the ground, turn into forest steeplejacks.
All plants need light to live. Competition for it in the tropical forest is very high. In the lower tiers of the forest there is constantly not enough light, and most plants are simply not able to survive. The evolution of grasses under these conditions went in several directions.
Some species remained to live in the lower layer of the forest, adapting to low light conditions. Other plants were forced out onto the edges, river floodplains, or clearings created by the fall of huge trees. Still others have developed the ability to climb other plants, entwining them with a flexible stem and clinging to branches and irregularities in the bark with tendrils, leaf petioles, roots and thorns - these are vines known to everyone, their number in the tropical forest is colossal and not a single one can do without mentioning them a story about travel in the tropics. And finally, some plants switched to an epiphytic lifestyle: they completely broke away from the soil and adapted to exist on other, larger plants.
In tropical forests, epiphytes live both in the uppermost layers and in the undergrowth, where lighting conditions are still somewhat better than at soil level (Fig. 1). However, not all epiphytes spend their entire lives high in trees. Many of them initially exist as ordinary terrestrial plants and only then, growing and forming apical shoots, attach to the tree and switch to an epiphytic lifestyle.
A similar mode of existence is characteristic of many vines and small plants that live in dense bushes characteristic of tropical areas. Other plants, on the contrary, having begun life as epiphytes, later form long roots that reach the soil. Having taken root, they begin to grow rapidly and often completely “absorb” the tree that served as their support. This type of growth is characteristic, in particular, of many ficuses.
Epiphytes and plants similar to them in structure are able to grow in the mountains on steep cliffs and scree. We will not specifically highlight a group of tropical rock plants (petrophytes), but will simply indicate when describing specific genera and species of epiphytic plants where they are most often found - on trees or on rocks. Moreover, it is quite difficult to draw an exact boundary between epiphytic, rocky and terrestrial plants (therophytes): there are many transitional forms. We must always remember this and not be surprised when a plant that naturally grows on the ground is grown indoors as an epiphyte, or, conversely, a seemingly typical epiphyte is cultivated as a terrestrial species. But let’s not get ahead of ourselves, but rather dwell on the specific features of epiphytes, which make it possible to distinguish this group from the many existing life forms of plants.
The morphological characteristics of a plant and the features of its biology are, as it were, an imprint of the conditions in which this plant lives. And epiphytes, leading such an unusual way of life, in the process of evolution acquired a number of interesting adaptations that ensure their survival and successful competition with other plants of the tropical forest.
We have already talked about how these often quite large plants manage to fly to a height of up to 60 m above soil level. In fact, the seeds of many plants can fly. Suffice it to recall the ubiquitous dandelion and maple, whose lionfish are carried by the wind for tens and hundreds of meters. In this sense, epiphytic plants did not invent anything new, but if for terrestrial plants flying seeds are only one of the ways to expand their range, then for epiphytes the ability of seeds to fly is the most important adaptation that ensures the survival of the entire species as a whole.
For flight, many epiphyte seeds are equipped with special “devices” that increase windage - various crests or lionfish. Some epiphytic plants, such as orchids, have such small seeds that they fly freely in the wind without any additional devices. Of course, with this method of dispersal, not all seeds find themselves in conditions favorable for germination, but this disadvantage is compensated by their quantity - there are several million seeds in one orchid seed capsule!
However, it is not only the wind that contributes to the dispersal of epiphyte seeds. Many of them are carried from tree to tree by birds. This is how rhipsalis cacti, some gesnerias and bromeliads spread.
Sometimes not only seeds, but also the plants themselves manage to “flip” from tree to tree. Seedlings are the most likely to travel: they are often carried from place to place by birds or other animals living in the forest canopy or collecting material for their nests there. The record holder among epiphytes should be recognized as Tillandsia usneoides, which is often called Louisiana, or Spanish, moss (Fig. 2). We must immediately make a reservation: this plant has nothing to do with mosses, but belongs to the extensive bromeliad family, which, in particular, includes pineapple. Tillandsia flowers are small and produce few seeds. Despite this, it is very widespread and is not due to its seeds.
Strongly overgrown specimens of this plant hang from the branches of trees in long tufts that are colored silver-gray, and from a distance they are very reminiscent of some types of lichens. The wind ruffles and tears the free-hanging “beards” of tillandsia, throwing individual tufts onto neighboring trees. And they calmly begin to grow in a new place. Pieces of the plant are carried over quite considerable distances by birds: soft and hygroscopic bromeliad is an ideal material for building nests.
But no matter how interesting the method of dispersal of tillandsia may be, it is atypical for most epiphytic plants. The main device that ensures penetration into tree crowns is seeds.
Epiphytic plants are found only among families whose representatives have seeds adapted for flight or transportation by animals. Among families whose representatives have heavy seeds, for example among legumes, there are practically no epiphytes. It was the presence of devices that facilitate the spread of seeds that allowed certain representatives of various families to switch to an epiphytic lifestyle.
Readers who know botany well, having reached this point, will immediately object to us that such extensive families as the Poa and Asteraceae do not have epiphytic species, although their seeds are well adapted for flight or transport by animals. Indeed, the presence of appropriate means of dispersal is just one of the properties necessary for epiphytes. So what if the seed of some plant flew high above the ground and ended up landing on the top of a tree? This is clearly not enough. It must still be able to stay there, germinate, develop into an adult plant, form seeds or spores that could scatter to neighboring trees and give rise to new shoots. Not all species that have flying seeds are able to travel this path. Here we need special devices that allow us to exist in completely unusual conditions. Their presence distinguishes truly epiphytic plants from random guests” thrown into the crown of a tree by chance.
Firstly, the seed of an epiphytic plant that has begun to germinate must be securely attached to a trunk, branch or rock. This requires a well-developed root system. Even tiny, smaller than a pinhead, orchid seedlings in the earliest phases of their development quickly form a mass of root hairs - rhizoids, which help them to hold on. And this task, I must say, is not easy. All-crushing hurricanes sweep over the tropical forest, uprooting huge trees from the ground. Masses of water fall on the forest during the rainy season, but tiny seedlings of epiphytes hold on tightly to life, releasing root after root, clinging to the smallest crack in bark or stone.
Mature epiphytic plants have a huge root system. Moreover, in many aroids and orchids it is clearly divided into feeding and attaching roots, which differ in their functions and structure. For example, in many orchids, the attaching roots have a flat, ribbon-like shape, which provides the greatest contact with the support. Attaching roots are usually firmly attached to the bark of a tree or a rock and do not grow vertically downwards, but seem to crawl along the support, following the depressions of the bark; often they grow parallel to each other, forming a wide (up to 10 cm) ribbon. Sometimes one of the roots growing nearby separates from the common ribbon and describes a loop around the branch. This is especially true for plants with long, creeping stems - some aroids, vanilla. As a result of such root growth, the plant stem appears to be tied along its entire length to the trunk or branch of the tree.
In some members of the bromeliad family, the specialization associated with the epiphytic lifestyle has gone so far that their roots have completely lost the ability to absorb nutrients and water. Their only function was to securely secure the plant. By appearance, and in terms of strength, such roots are most reminiscent of wire, and in order to break them, you have to spend a lot of effort.
Many epiphytes growing in deciduous forests, due to the fact that their root system is annually covered with more and more new layers of litter, form respiratory roots that grow vertically upward. This nature of the development of the root system allows the plant to master new layers of fresh substrate and provide the remaining roots with the oxygen necessary for respiration.
In some cases, the root system of epiphytes is capable of performing completely unexpected functions, for example, protecting the plant from enemies. To do this, many short (0.5-1 cm in length) sharp outgrowths are formed on the roots, and the stem of the plant appears to be surrounded by a coil of barbed wire, reliably protecting it from any uninvited guest who wants to feast on the young shoots.
The ability of epiphytes to establish themselves is truly amazing. Some of their representatives are able to stay on completely sheer rocks, walls of houses, telegraph poles and, as we have already mentioned, wires.
But, despite the excellent “tenacity” of epiphytes, not all trees in the tropical forest are equally successfully colonized by them. Some trees have completely smooth bark, which not every epiphytic plant can support. Others, especially those with fragile wood and easily breaking off branches, unable to withstand greatly expanded epiphytes (and their weight after heavy rains can reach several tons), attract certain types of ants into their crowns, which clear the branches of epiphytic plants.
In tropical countries, ants play a very important role in the life of the forest community. Their traveling colonies and powerful anthills represent a powerful force, capable of defeating or driving out any enemy. Ants deal with young epiphytes quickly and mercilessly. When scientists experimentally attached bunches of epiphytes to the branches of some trees, the ants completely destroyed them in just a few days!
But epiphytes can also attract ants to their side and coexist with them in a kind of symbiosis. The adaptations developed by epiphytes to attract ants are often very “witty” and unexpected. Thus, in the epiphytic plant Myrmecodia (Fig. 3), common in Indonesia, a large tuber is formed on the stem, which has interconnected passages and cells inside, opening onto the surface of the tuber with holes. These tubers are usually inhabited by ants, which protect the plant from pests and provide it with additional nutrition in the form of excrement and food debris. The ants themselves do not take any part in creating the anthill located inside the tuber. Scientists have found that cavities inside myrmecodia tubers form even when the plant is not inhabited by ants.
Some orchids (for example, Schomburgia) also have hollow stems adapted for ants to live in. Other orchids (for example, diacrium) form balls of tangled roots to attract ants. An equally interesting adaptation is the dischidia rafflesiformes, which develops peculiar pockets from the leaves with a funnel-shaped hole at the top. Ants also often settle in these sac-like formations, in whose nests soil gradually accumulates, feeding the plant.
However, ants are not always content with the role of passive “guests”, only populating anthills prepared for them by plants. Brazilian Camponotus and Aztec ants sometimes become real gardeners and create huge anthills on trees, made up of various types of epiphytes.
Ant hanging gardens are one of the most unusual structures built by insects. Ants lay out their buildings according to all the rules of gardening art. First they choose a suitable place - most often a strong fork in the branches. Then soil preparation begins. To do this, six-legged builders bring small lumps of earth to the tree, which are glued together at the top with saliva and feces. As soon as enough land has accumulated, sowing begins. Scouring the treetops, the ants collect the seeds they need and sow the prepared soil. As the seeds germinate, the ants continue to drag up more and more portions of earth, carefully covering the roots of the sprouts with it, so along with the “garden” the earthen lump, inside of which the ant’s nest is located, also grows.
Ants select plants for their nest-garden very carefully. In the middle of the anthill they usually sow different kinds bromeliads, and closer to the edges - gesnerias, ficuses, peperomia and orchids. Plant roots strengthen the walls of the earthen nest, making it resistant to tropical downpours. The plants themselves suffer less from drought and also receive additional nutrition in the form of leftover food from their “owners”.
The symbiosis of plants with ants is such an interesting phenomenon that we involuntarily digressed from our main topic. Indeed, ants help certain types of epiphytes to exist successfully by creating soil for them and providing optimal water conditions. But how do other epiphytic plants get out of this situation?
Epiphyte habitats are characterized by an almost complete absence of soil. Plants depend on the small amounts of minerals and plant debris that accumulate in the cracks and depressions of the bark or stone. In addition, epiphytic plants sometimes live in conditions of extremely irregular, and often simply insufficient, moisture, since streams of water flow down branches or tree trunks to the ground, and the wind and sun quickly dry out the small amount of moisture that is retained in small depressions! Based on this, the main morphological features of epiphytes, which distinguish them from other life forms of plants, are adaptations to existence in conditions of lack of soil and moisture. They were described in detail almost 100 years ago by the German botanist Schimper. His works on epiphytic plants are cited in almost every botany textbook.
Having studied the features of adaptation of epiphytic plants to living conditions, Schimper in 1888 compiled a classification in which he divided epiphytes into four groups: protoepiphytes, nesting and bracket (pocket) epiphytes, reservoir (cistern) epiphytes, semi-epiphytes.
Protoepiphytes represent the least specialized group of epiphytes. They are only to a small extent protected from periodic droughts and lack of soil. Protoepiphytes do not have special structures for collecting water. Many protoepiphytes have features characteristic of plants growing in arid regions of the globe, or, as botanists say, have a number of xeromorphic features. Most epiphytic plants classified in this group have fleshy (succulent) leaves that can retain some moisture. Such leaves are common for some peperomia, lastovniaceae, and gesneriaceae. Some liana-like epiphytes store water in thick, fleshy stems. In many orchids, one or more internodes of the stem become very thick, turning into peculiar above-ground tubers (tuberidia), which in the floriculture literature, according to an established tradition, are not entirely correctly called bulbs (bulbs) or pseudobulbs (false bulbs).
Of particular interest is the structure of the root system of protoepiphytes. Many of them develop a huge number of roots covered with a special water-absorbing tissue - velamen. The velamen consists of dead, suberized cells (Fig. 4). During rains, it becomes saturated with water and becomes a container from which the plant receives moisture in the periods between rains.
Another feature of velamen is its ability to absorb moisture from air saturated with water vapor. This property of velamen allows plants to successfully survive fairly long dry periods. In dry, hot weather, the air-filled cells of the velamen play the role of an insulating layer that protects the roots from overheating and excessive water loss. Isn't it a convenient and universal device? The presence of velamen is characteristic of many protoepiphytes belonging to various botanical families, although it is most often found in epiphytic orchids.
However, Schimper found out that velamen is also found in a number of herbaceous plants living on the soil. It has even been suggested that these plants are epiphytes that have returned to a terrestrial lifestyle. However, most scientists; believes that this is not so. Velamen, present in terrestrial plants, is just one of the signs that allow the transition to an epiphytic existence, similar to the light flying seeds that provided epiphytes with the opportunity to climb high into the crowns of trees.
In general, the question of the ancestors of epiphytic plants has not been completely resolved by scientists to this day. Some believe that epiphytes originated from terrestrial plants that grew in damp and shady places. Others, objecting to them, point out that most epiphytes are light-loving plants and could not have evolved from shade-tolerant ancestors. In their opinion, the ancestors of epiphytes were drought-resistant plants, living in desert and semi-desert areas located on the border of tropical forests (the latter statement appears to be true for some epiphytic representatives of bromeliads and cacti). It is quite possible that a clear answer to the question of the origin of epiphytes is simply impossible.
After all, it may be so: some epiphytes originated from herbaceous plants of the lower layer of the tropical forest, while others are descendants of xerophytes that came to the tropical forest from deserts and semi-deserts. In our opinion, this is exactly what it was, but let's leave the solution to this problem to the botanists and return to considering the abilities of the main groups of epiphytic plants.
Nesting and bracket (pocket) epiphytes have adaptations that allow the accumulation of various organic residues, which over time turn into humus and provide the plant with nutrition.
In nesting epiphytes, which include many ferns, aroids and orchids, the roots form a tightly intertwined mass, vaguely reminiscent of a bird's nest. Dead leaves and other plant debris falling from above are retained in this trap and, gradually accumulating, turn into humus. In addition, ants, centipedes, and worms often make nests in the intertwining roots. As a result of their vital activity, the decomposition of accumulated plant material is significantly accelerated, and the nutrients contained in the humus become available to the plant.
In brackets of epiphytes, all or part of the leaves adjacent to the tree trunk form peculiar funnels, or pockets. Humus gradually accumulates in them (which is largely facilitated by ants and other invertebrates). The leaves from which the pocket is formed are vaguely reminiscent of parentheses in cross-section - this is precisely the reason for the unusual name of this group of epiphytes. There is another name for these plants - pocket epiphytes, indicating the ability to accumulate humus in special pockets.
The most famous representative of bracket epiphytes is the staghorn fern (Fig. 5). It produces two types of leaves (vai). Leaves of the first type are called integumentary leaves; their lower part fits tightly to the trunk, forming a pocket open upward. The leaves of the second type (sporophylls) are highly branched like deer antlers, they hang down freely and carry sporangia with spores at their ends. As the plant grows, the leaves forming the pocket gradually die and rot, and new ones form on top of them.
In terms of the method of accumulation of humus, Dischidia rafflesiformes is very close to bracket epiphytes (Fig. 6). We already mentioned this unusual plant, when they talked about the symbiosis of epiphytes with ants. It looks very strange. Judge for yourself - neither roots nor leaves are visible: on a long cord-like stem about half a centimeter thick, at irregular intervals there are incomprehensible formations 10-15 cm long, reminiscent of wrinkled bananas. It is these light green “bananas” that are the modified leaves of dischidia, turned into bags suspended from a creeping stem. At the top of each such bag there is a small hole. Dischidia also has roots, but they do not grow in the soil, like other plants, but inside leaf bags. During rains, water gets into the bag, various plant residues gradually accumulate, and, as we have already said, ants settle in - in general, if you consider that on one relatively short stem there can be several dozen leaves-reservoirs at the same time, it becomes clear that dyschidia does not suffer from hunger.
Reservoir (cistern) epiphytes most adapted to life on other plants. They are found only in the bromeliad family. We are already familiar with one of its representatives - tillandsia, but this plant is very different in structure from most bromeliads.
Typical bromeliads, such as Aechmea fasciata (Fig. 7), have long hard leaves, assembled into a socket. Moreover, they overlap one another so tightly that they form a waterproof reservoir. In some plants it can contain up to 5 liters of water. In addition, in some representatives of this family, the inner leaves close together at the top of the tank so tightly that water does not pour out of it, even if the plant is turned over.
Water accumulating in bromeliad funnels eventually mixes with various forest debris, plant and animal debris falling from above. As a result, a kind of suspended swamp is formed high on the tree, in which animals and plants settle.
The flora and fauna of bromeliad tanks is extremely unique and abundant. For example, some Brazilian species of pemphigus ( Bladderworts are a genus of insectivorous aquatic herbaceous plants of the bladderwort family. The leaves of bladderwrack are covered with spherical vesicles in which small aquatic animals trapped there are digested.) can only be found in bromeliads and nowhere else. Various small land animals find food in the humus that accumulates on top of the water. The water breeds tree frogs, mosquito larvae and aquatic insects. The ponds formed in large thickets of bromeliads are so large that many scientists talk about suspended swamps in the forests of tropical America and seriously discuss their role in the tropical forest ecosystem.
Bromeliads absorb water from their storage not with their roots, which in many of them are generally unsuitable for this, but with their leaves. For this purpose, on the surface of bromeliad leaves there are special suction scales - trichbmata. The trichome operates on the principle of a water pump (Fig. 8). When moisture enters, the wing cells, which are folded like an accordion when dry, straighten out and increase in volume.
They are helped in this by ring cells that act as filters. As water enters, the pressure in the cells quickly increases, and water rushes to the living cells of the arch and further into the aquiferous tissue of the leaf, which bromeliad leaves are very rich in. Along with water, the plant also receives nutrients extracted from the humus accumulated in the funnels.
By the way, the already familiar Tillandsia (Louisiana “moss”) absorbs water in the same way. Only she doesn’t have a funnel, and she has to be content with the water that she manages to extract from the air or capture during the rain.
The specialization of bromeliads has gone so far that many of them have learned to obtain moisture and food without the participation of the root system. However, this does not bother them at all, and representatives of this wonderful family have spread widely across the American continent, where they can be found almost everywhere - from deserts and semi-deserts to tropical forests and mountains.
Semi-epiphytes. The very name of this group of plants suggests that its representatives are only half epiphytes. They begin their existence as true epiphytes - high on a tree, but then, developing long aerial roots, they reach the soil and take root in it. This is how many large aroids, ficuses and a number of representatives of other families grow. Having a close connection with the soil, semi-epiphytes do not experience a lack of water and nutrients. Moreover, some representatives of this group can, depending on conditions, exist as independent plants (including trees) or become epiphytes with roots reaching down to the ground.
In this chapter, we talked about the main adaptations developed by plants during the transition to an epiphytic lifestyle. We hope you are convinced: epiphytes are extremely interesting and unusual plants. Of course, only the most general features of their structure are considered here, but we will certainly return to this issue when describing specific families and species.
As you know, all plants in nature adapt to the conditions in which they are forced to exist. A striking example epiphytic plants are such adaptation to life. In the forests, where there is an irreconcilable struggle among plants for the sun, epiphytes(translated from Greek: “on the plant”) were able to coexist perfectly with other plants. They not only receive light, but also thus protect themselves from land animals.
Such mutually beneficial “cohabitation” of plants different types called symbiosis. In science the term symbiosis denote the long-term coexistence of two different species, which not only does not harm any of them, but also helps the plants survive. A typical example of symbiosis in flora- coexistence of orchids and lianas in the tropics.
Tropical forests contain the richest communities of epiphytes. The most striking representatives of epiphytes in the tropics are, for example, orchids, tillandsias and other plants of the bromeliad family, some species of schefflera, nephrolepis, and some types of ficus. In the forests of the temperate, as well as the coldest arctic zone, the most common epiphytes grow - mosses and lichens.
All epiphytes can be divided into four groups:
1. Protoepiphytes. This group includes the least adapted epiphytes. They have no protection from droughts and lack of soil. Some members of this group have very thick, fleshy leaves, like succulents, which retain a small supply of moisture. In others, the water supply is carried out in the stem. In some orchids, one or two internodes on the stem are thickened and very similar to above-ground tubers - tuberidia. or pseudobulbs.
2. Nesting and bracket epiphytes.
In representatives of nesting epiphytes, for example, ferns, and some types of orchids, aerial roots form a very dense mass, similar to a bird's nest. Fallen leaves and other plant debris accumulate in these “nests” and gradually rot. This compost of plant residues becomes a source of nutrients for epiphytes.
In bracket epiphytes, at the point of attachment to the support tree, the leaves form real pockets, or funnels. If you look at these leaves from above, they resemble parentheses (). They also accumulate plant debris and moisture. An example of a bracket epiphyte is the Antler fern.
3. Reservoir epiphytes. They are the most adapted to life on supporting plants. They have very hard leaves collected in a rosette. The outlet itself is a reservoir in which a lot of moisture can accumulate (up to 4-5 liters!). Representatives of this group of epiphytes are plants of the Bromeliad family.
4. Semi-epiphytes. At first, these plants begin to develop like real epiphytes. Subsequently, long aerial roots grow to the ground and take root. These epiphytes then obtain nutrients from the soil. Representatives of this group of epiphytes are ficus.
Lianas are a variety of climbing plants, both woody, with evergreen or deciduous leaves, and herbaceous, with relatively weak thin perennial or annual stems. Not being able to stay in the air freely, they find vertical support with the help of antennae, adventitious roots, and trailers and rise high in the air, where they develop foliage and flowers.
Curly leaf petioles:
Clematis twines around supports with very flexible leaf petioles. The petioles reach out to the stems of the host plant and grab onto them, pulling the entire vine along with them in search of other supports. The tendrils can curl both clockwise and in the opposite direction, making the vine’s grip on the support more reliable.
Climbing stems:
In some plants, the growing stems find support and make circular movements until they find support. Most vines have a leading stem that rotates clockwise.
Aerial roots:
Another effective method attaching vines to a support - the use by plants of a mass of small “roots” growing from the stem. They grip the surface tightly and allow the strong ivy stems to grow in all directions.
Plants - pillows, or cushion plants-life form of plant organisms, which is characterized by numerous short shoots, the tops of which form a single surface. This type of vegetation arose in extreme conditions of sudden changes in temperature and strong winds, which is typical for lowland and mountain deserts and semi-deserts.
Epiphytes- plants growing on other plants - forophyte, or permanently attached, while not receiving any nutrients from the phorophytes.
Nesting and bracket (pocket) epiphytes have adaptations that allow the accumulation of various organic residues, which over time turn into humus and provide the plant with nutrition. Reservoir (cistern) epiphytes most adapted to life on other plants.
Semi-epiphytes begin their existence as true epiphytes - high on the tree, but then, developing long aerial roots, reach the soil and take root in it
37 Excretory tissues of plants. Types of containers.
excretory are called fabrics, excreting substances excluded from metabolism.
Secretory tissues are very diverse in morphology and topography in the plant body.
There are two types of excretory tissue - external and internal secretion.
The first type includes various glandular hairs and glands, nectaries.
The second type of excretory tissue includes resin canals (resin ducts), secretion receptacles, idioblasts (specialized cells), and lacticifers (milky tubes).
Excretory tissues of external secretion:
Glandular hairs represent trichomes, i.e. derivatives of the epidermis formed without the participation of underlying tissues. Glandular hairs can be sessile, have a multicellular head, etc.
Glands are called Emergents, if not only the epidermis, but also deeper-lying tissues participate in their formation
Internal secretion containers or containers of secretions are very diverse in shape, size and origin.
Distinguish schizogenic And lysigenic containers. The first appear in the form of intercellular spaces filled with secreted substances and surrounded by living epithelial cells. The latter arise at the site of a group of cells that disintegrate after the accumulation of substances.
Channel-shaped excretory devices are named according to their contents oil, resin, mucus And gums moves.
Schizogenic resin canals(resin ducts) are long tubular intercellular spaces filled with resin and surrounded by living cells epithelium.
Schizogenic receptacles of essential oils contain an epithelial layer of tightly closed excretory cells, often of an isodiametric shape. Essential oils or resins are formed inside the epithelial cells and released into the cavity of the gland.
IN lysigenic containers excretory cells dissolve; Their shells are also destroyed, of which only sometimes remains remain. The cover and container of the resulting secretion is a tightly closed layer of cells of the main tissue surrounding the intercellular space with the secretion.
Excretory cells (idioblasts) accumulate various substances: calcium oxalate crystals (single crystals, druses, raphides, etc.), mucus, tannins, essential oils. They are found among cells of different tissues and can have a variety of shapes and chemical compositions.
Milkies(milky tubes) perform various functions - conducting, storing, excretory. Their wall consists of cellulose. These are living cells with cytoplasm, many nuclei and a vacuole filled milky juice (latex). There are two types of laticifers: articulated and non-articulated.
Articulated are formed in the same way as vessels, as a result of the destruction of the transverse walls of a vertical row of cells.
Unarticulated laticifers arise as a result of the proliferation of special cells of the embryo. These are giant cylindrical or branched cells
