Description of the parasite plant. Parasitic plants: general characteristics and types. fungi and bacteria

... And lurking on black branches Unconscious trouble ...

A. Zhigulin

How does a plant live?

And the hundred-year-old oak in the grove, and the beautiful rose in your garden, and the inconspicuous plantain by the side of the road, and most other plants that you know and those that you don’t know - they all eat the same way. The leaves “catch” carbon dioxide from the air, and the roots “pump” water from the ground and supply it upward through the vessels. In the green, chlorophyll grains of leaves, illuminated by the sun's rays, a miracle happens: transparent, colorless carbon dioxide, which is impossible to see, and ordinary water, when combined, form sugar or starch - substances that look and taste completely different from those from which they were created. In addition to sugar, oxygen is also formed here, which immediately flies into the air.

This can't be reached, others have! Over there, through the foliage of an old birch, one can see some shaggy round tangles of tangled branches, like nests of large birds. However, these are not nests. These are mistletoe bushes. Mistletoe has adapted to suck the juices of the branches of large trees and settles high, high, at the very top of the tree. It is much safer to live on tall trees than on the ground - not a single herbivore will touch. But how did she get there? To answer this question, you need to approach a tree affected by mistletoe in winter. Against the background of bare dark branches and branches of a tree, mistletoe is very effective. The bushes of this evergreen plant are covered with dense leathery leaves even in winter. Since the leaves sit at the end of each forked branch, a green ball is obtained, sometimes reaching large sizes. Snow-white berries are interspersed in the green of the mistletoe leaves, shimmering in the sun with a pearly sheen. These berries ripen only by winter and sit very firmly on the bush. Mistletoe berries are quite edible. Most of all, they are loved by thrushes and waxwings. The pulp of the berry is sweet, slimy and sticky. And inside the pulp lies one or two seeds. The bird pecked at these berries, and her beak became sticky. Having flown to a neighboring tree, she cleaned her beak on a thin branch and ... firmly glued the mistletoe seed to the branch. 4A few hours later, having flown away from the place of the feast, the same bird left a droppings on a branch of some tree. And in the litter there is a mistletoe seed. It did not lose its germination from the fact that he had to pass through the intestines of a bird. The seed took refuge in a slightly noticeable deepening of the old branch, where it will lie until spring.

In the spring, when the juices of the tree run faster through the vessels, awakening young leaves to life, the mistletoe seed will sprout. The root of the seedling will certainly grow towards the branch of the tree. No matter how you turn the seed, no matter how you put it, the stubborn root will still reach for the branch. A slightly noticeable warmth emanates from it, it casts a slight shadow, and the mistletoe seedling, better than a sensitive device, perceives this heat and this shadow. Having reached the bark of a tree branch, the root sticks to it, and soon, at the place of its attachment, a round dense cushion-shaped plate swells up, from the middle of which thin, strong, sharp, like needles, shoots grow. They pierce the bark of a tree branch, grow inside the bark, and gradually reach the wood. The cuttings cannot penetrate into the wood. But every year new, fresh layers of it grow outside the wood. These layers envelop the shoots on all sides so that after a few years they are immersed in the wood and firmly hold the mistletoe sprout on the branch. During this time, side shoots will grow from the main shoots, and the entire inside of the branch will turn out to be entangled in a network of shoots of a foreign plant, which in the dark interior of the tree pump out water, mineral salts and caxapa from it day and night. Such processes are called haustoria.

Outside, on the branch for the first two or three years, almost nothing is noticeable. And only five years later, a mistletoe stalk with leaves appears, which branches more and more every year, growing into a green bush. Mistletoe lives for a long time, sometimes up to forty years. During this time, the bush manages to reach a huge size. That section of the host's branch, on which the mistletoe settled, gradually swells more and more, forming in this place, as it were, a tumor. This is because mistletoe haustoria suck too many nutrients from the depths of the tree. Mistletoe can't use them all. An excess of these nutrients causes an abnormally rapid growth of the tree at the site of attachment of the mistletoe.

And what's interesting! Since the leaves of the mistletoe are green, since the mistletoe settles on the tops of trees, where many sunlight, these leaves themselves diligently produce caxapa and other substances necessary for the life of the plant. It would seem that if the nutrients of the tree can get into the mistletoe bush, then the reverse current is also possible - when the nutrients produced by the mistletoe would fall into the host's vessels. So no! This never happens. The mistletoe is designed in such a way that it only takes without giving back. And he takes too much. With a strong development of mistletoe, almost no water enters the branches of the tree located above it, and therefore they dry up. It happens that the mistletoe sits on a tree so densely that in winter the unfortunate tree seems to be one grandiose mistletoe. It happens that this parasite occupies vast areas of forest plantations. For example, in the west of Austria, in Tyrol, where the slopes of the mountains in the valleys of the Aisach and Etsch rivers are occupied by continuous plantations of pine, there are a great many mistletoe. On one tree there can be up to a hundred of its bushes.

What's the matter? It turns out that it is here, along the valleys of these rivers, that the air route of thrushes, returning in the spring after wintering, runs. Hungry birds pounce on the delicious mistletoe berries left over from the winter and, flying from tree to tree, infect them with mistletoe more and more. There is so little unaffected space on the trees that sometimes it comes to curiosities: mistletoe seed falls on the branches of an adult mistletoe, germinates there, and eventually a young one grows on the old mistletoe. The old mistletoe sucks the juices from the tree, and the young mistletoe sucks the old one.

In autumn, a great many dry boxes appear on the dodder, each of which contains four round small seeds. Up to thirty thousand seeds can ripen on one copy of dodder. And then each seed has its own destiny. Some seeds along with grass will be eaten by a cow or a horse. They will be unharmed in the manure that you know is used to fertilize the fields, and thus fall into the plowed soil away from the mother plant.

Other seeds will stick to the wool of the same cow, or to the wheels of a tractor, or to the shoes of the people who work the field, and they will travel unseen.

Of course, most seeds will die without finding suitable conditions, but some ... Here, under last year's withered blade of grass, a round dark dodder seed lurked. Inside it, like a clock spring, a tiny embryo is coiled into a ring. He is biding his time. He is waiting for warm days to come and all the plants around him to grow enough. As soon as the seed peel bursts and water penetrates inside, the swollen embryo straightens and turns into a seedling. Its thickened lower end grows into the soil, and the upper filiform, rapidly increasing, makes slow circular movements, making it easier for him to meet with some plant. Gotcha! The tip of the seedling touched the stem of its neighbor. Now this seedling, as if alive, makes two or three small turns around its prey, and the quickly grown teeth dig into the young body of the stem. From now on, responsibilities are distributed until death: one works, the other eats.

Dodder is harmful not only because it suffocates useful plants and robs them of their nourishing juices. It also carries infectious diseases from one plant to another. Let it be known to you that the green kingdom has its own contagious diseases caused by viruses. A person is afraid of the influenza virus, and beets are afraid of the leaf curl virus. There are quite a few such viral diseases in plants. The dodder sucks on a diseased plant and, together with the juices, absorbs viruses that spread throughout its filamentous body without causing any harm to it. But when the thread of this dodder sticks to a healthy plant, the virus will be able to penetrate into the wound through the suction cups.

The fight between man and pest has been going on with varying success for many decades - from the very day when some emigrant from hot countries first sowed in his field the seeds of flax, or alfalfa, or, perhaps, carrots he had brought from his homeland, among which lurked dodder seeds.

The seeds of all broomrapes are small and light, like dust. They are not even visible to the naked eye. Picked up by the wind, they are transported over long distances, settle on the ground and can, without losing their germination, lie in the ground for eight or even ten years and wait if their owner grows nearby. How do they know if it's the owner or not? And it's very simple. The roots of any plant secrete special substances into the soil, as if their identification marks. So, for the germination of a broomrape seed, it is necessary that the root secretions of its host fall on this seed. Only then will the microscopic embryo begin to grow and turn into a tiny filamentous seedling, which, with its growing end, will stick to the nearest small root of the plant.

But, it turns out, she has control. The microscopic fungus Fusarium lives in the soil. And although the size of the broomrape is a giant for him, nevertheless, the fungus easily copes with it. Its juices unmistakably kill the broomrape, no matter how large it is and no matter how widely it breeds. For other plants, the fungus is harmless. Therefore, in the southern regions of our country, where broomrape is especially abundant, Fusarium is specially bred and artificially introduced into the soil in order to protect cultivated plants from infection.

In the Karakum desert, the hot sun mercilessly burns out all living things, leaving only those stranded plants that have managed to adapt to this heat, to this dazzling light, to these waterless loose sands. Mostly shrubs grow here with narrow leaves covered with a wax coating - juzgun, comb, saxaul. Their powerful roots reach an unimaginable length, many times the height of the aerial part. The roots draw water from the cool depths of the earth and bring it up to the leaves, which spend the precious gift carefully and economically.

deciduous forest in early spring quiet and transparent. The bare branches of the trees, caressed by the piercing light of the blue sky, froze in anticipation of the annual surprise: new shriveled leaves are about to appear from swollen and cracked buds. There is no snow at all. A wet carpet of last year's fallen leaves, soaked in snow water, still lies on the ground in a heavy layer that has caked over the winter and reluctantly passes through itself the seedlings of new life.

All year round Peter's cross lives underground and only on a short time exposes the upper part of the inflorescence outward to be able to scatter the seeds away from the mother plant. Invisible to anyone, inaccessible to enemies, eating other people's food, this underground plant lives without worries. long years. Only its inflorescence, which has met the sun, is doomed to annual death. But a new inflorescence will inevitably appear to replace the dead one next spring, and again the round seeds, driven by wind or water, will roll throughout the forest until they bury themselves in the roots of the tree, on which, after germination, it will be possible to cling to the suckers of the root.

Now imagine that we are in Indonesia, on the island of Sumatra or Kalimantan. A solid green wall stands majestic, harsh, dense jungle. A gloomy twilight reigns in the forest. The branches of the trees are intertwined so closely, their crowns are so dense that they do not let a single ray of the sun into this realm of rotten moss and sinister vines. Very stuffy. The still air is full of sharp smells of rotting leaves, wet greenery and some tart-smelling flowers. The forest is whispering something. Something crackles and rustles. The jungle has its own habitual, unknown to us life. Unfamiliar, alien, fairy-tale world.

Around the bend, the path dived between thick lashes of a cissus liana that curled around a tall tree. The roots of the creeper snake along the ground, somewhat rising above the surface of the soil. The elephant casually stepped heavily onto one of the roots and walked on. And the seed stuck to the root of the vine. Small, weak, harmless. But here after tropical rain the seed let out a tiny root. Like a gimlet, the root stuck into the rough, hard bark of the root of the creeper. And sprouted further, inside it. From that time on, the root meekly feeds the stranger for many years, giving its juices to the colossal flower.

Botanists were interested in the question: why does the seed of rafflesia germinate on the roots of the cissus liana, and die on the roots of other trees? It turns out that the germination of this seed and the further growth of the seedling can take place only if the germinated root absorbs the substances secreted by the roots of this vine only. Other plants do not emit such substances.

So, the Rafflesia seed sprouted and took root in the root of the vine. The single root of the seedling quickly branches into thin long threads, and, finally, a tangled ball of such threads, growing stronger and stronger inside the root of the host plant, entangles the wood of this root with a dense cover. The filaments continuously absorb food obtained by the host plant for themselves. Finally, a bud appears on the surface of the cover inside the root of the vine. It gradually increases, breaks through the root and comes out. The threads of the cover regularly drive the juices of the host plant to the kidney, and it keeps growing and growing, turning into a bud. First, the size of an apple, then like a head of cabbage, then like a huge pumpkin, and finally, spreading a fetid smell around it, the bud opens and the Rafflesia flower blooms. Previously, local residents on the island of Java, every time another monstrous flower began to open, arranged ritual dances around it, considering rafflesia to be sacred. No wonder, it is difficult to be indifferent to such an unusual phenomenon of nature.

In addition to Rafflesia Arnoldi, its closest relatives can be found in the tropics. All of them lead the same way of life, they are deprived of both stems and leaves, only their flowers are much smaller.

The stems of the plant are usually pencil-thick, but the largest mistletoe have trunks 5 cm thick. Mistletoe sometimes lives up to 40 years.

Well "thought out" nature way mistletoe settling. In September, white mistletoe ripens sticky white berries (for which it got its name). In the old days, glue was prepared from these berries for catching small birds, thanks to which white mistletoe received another name - “bird glue”. For a person, the berries of white mistletoe are inedible, but birds, especially blackbirds (see the article “Thrushes and nightingales”), are great hunters before them. In the bird's stomach, the seeds make their journey to new "places of residence". Now much for them depends on "luck". If, together with bird droppings, they fall to the ground, they will die. And if they find themselves on a tree branch, they will stick to it with the remnants of undigested sticky pulp. In the spring, the seeds will begin to germinate: they will release a root that will pierce the bark and grow into the branch of the host plant. The root of the mistletoe copes with the bark of young branches without difficulty, but it can also “gnaw through” the bark of 60-year-old branches, using organic acids. The mistletoe will never have real roots; they are replaced by sucker roots that draw life-giving moisture from the host plant. In the second year of life, the mistletoe will grow leaves.

The "living vehicle" that mistletoe uses to spread has its drawbacks. Digestion in birds is very fast - the berries are completely digested in less than half an hour. The Australian biologist V. Serventi explained by this that there is no mistletoe on the island of Tasmania, although it is very common in Australia. From Australia to Tasmania - more than an hour of bird flight, and the seeds do not have time to reach their destination, falling into the sea.

PETROV CROSS. Unlike mistletoe - a green plant - Peter's cross (Lathrea squamaria) from the cinnamon family is completely devoid of chlorophyll: only small scales remain from its leaves. This parasitic plant can be found in central Russia on the roots of hazel (hazel), alder, linden.

True, ten months a year the plant is hidden underground, where its rhizomes receive nutrients. For this, Peter's cross was also called the secret. Here no one tears it, tramples it, and herbivores do not eat it. Raspberry one-sided brush of flowers on a pale fleshy stem looks out into the white light only once a

Petrov cross.

a powerful tool for overcoming demonic enemy forces,” wrote P. Sedir, author of the book “Magical Plants”.

RAFFLESIA ARNOLDI. Rafflesia Arnoldi has not only chlorophyll, but almost no organs at all - no leaves, no roots - nothing but a giant (up to 91 cm in diameter) flower. (There are, however, mushroom-like filaments that pierce the tissue of the host plant.) This is the most big flower in the world (we already talked about it in the “Flower” section of the article “Organs of Higher Plants”).

Even for a tropical forest, this flower is very unusual. Therefore, on the island of Sumatra, where Rafflesia Arnoldi grows only, the local population considered it sacred and worshiped it. Rafflesia was discovered for science in 1818 by the botanists Raffles and Arnoldi.

LEGENDS ABOUT MISTLE

A person who, at the beginning of our era, found himself in one of the sacred oak forests of the ancient Gauls, could witness the ceremony of worshiping mistletoe, a mysterious plant that settles on tree branches. The Gauls believed that mistletoe had an all-healing power, and to cure any disease, it was enough just to touch it.

The ceremony took place on the day of the winter solstice (December 22), when the “kingdom of the night” ends, after which the daylight hours begin to gradually increase. At this time, the healing power of mistletoe was considered the greatest. A pair of white bulls, which had never before worn a yoke, were driven into the oak forest. Sacrificial animals, as it were, sanctified the entire ceremony. The priest (druid), dressed in snow-white clothes, climbed an oak tree and cut off the mistletoe with a golden sickle, which was picked up in a white scarf. Branches of evergreen mistletoe were used to decorate dwellings and temples.

The veneration of mistletoe did not completely disappear in France, although Catholic priests forbade even sprigs of this "pagan" plant to be brought into the church. " New Year with mistletoe!" - the French peasants wished each other happiness in the new year. Until now, in England and France at Christmas, a sprig of mistletoe can be seen above the doors of houses. And in Australia, native species of mistletoe serve as "Christmas trees."

Legends and myths about mistletoe were composed by many nations. According to Scandinavian mythology, the wise and brave god Baldur was once predicted to die violently. His mother, the goddess Frigga, took an oath from all living and inanimate creatures, from all plants growing in water and on earth, that they would not harm her son. Only from the insignificant mistletoe growing on the branches of trees did she forget to take this oath.

Baldr became invulnerable to any weapon, and the gods sometimes amused themselves by shooting at him, which could not harm him. But the evil and treacherous god Loki made a deadly arrow from a mistletoe twig and imperceptibly planted it at such a moment to the blind god Hod. God Hod fired and killed Balder.

And among the ancient Greeks and Romans, mistletoe served as the prototype of the "golden branch". The fact is that although fresh leaves of mistletoe are bright green, dried up, they become golden yellow and hard, resembling gold. In Virgil's poem "Aeneid", the soothsayer gives the following advice to the mythological hero Aeneas, who wants to see his dead father:

Hear what to do

You will have to. Hidden in more often

Branch, all of gold,

and the leaves on it are golden.

Only the golden branch opens the way for a living person to the underworld of the dead.

CONTAMINATION "CHI

Plants from the broomrape family fully justify their name. This is malicious weeds, harmful to crops of sunflower, tobacco, tomato, hemp, etc. Having stuck to their roots, broomrape, like contagious diseases, sometimes completely destroy crops. Broomrape is easy to distinguish on the field: its stems can be painted white, brown, bluish, brown colors, but not in green, because they do not have chlorophyll.

It is curious that the seeds, which the broomrape abundantly scatters from its fruit-boxes, do not germinate until they "feel" the excretion of the roots of the host plant nearby.

SANDAL

The body itself does not produce nutrients. In nature, there are a huge number of living organisms, namely plants that feed on substances synthesized by other representatives of the flora. This way of survival has been around for quite some time. It occupies a special place in ecosystems.

One of the brightest representatives of this species is As soon as the snow melts, this plant begins to develop rapidly. It has pink inflorescences and resembles a candle. This plant is not capable of photosynthesis and therefore does not have green leaves and stems. Peter's cross grows on the roots of trees (alder, poplar, hazel). His root system, consisting of white branched roots, grows together with the roots of the tree. It can reach quite large sizes. Its roots are covered with scales arranged crosswise. That's why it's called that. This plant can only be seen in spring. Its seeds ripen quickly and fall off.

It feeds on mycorrhizal fungi. In this regard, it can be found in the midst of mushroom picking. The mushroom picker feeds, and then, in turn, is a power source for the picker, supplying him with useful material mycorrhiza.

Typical symptoms of bacterioses are dwarfism, discoloration, wilting, rot and the formation of cancerous growths.

fungi and bacteria

Typical symptoms of bacterioses are dwarfism, discoloration, wilting, rot and the formation of cancerous growths. A typical example of diseases of this type is root and root collar cancer in many plants, caused by Pseudomonas tumefaciens Sm. with. T. In the process of life, these bacteria secrete substances that stimulate increased growth and division of plant cells, which leads to the formation of tumors, bulges, thickenings on the trunks and stems, which after a while rot and collapse.

A clear example of such an impact is the formation in the crowns of trees (alder, poplar, maple, elm, oak, birch) of the so-called witch's brooms when infected with mushrooms from the family Taphrinaceae. The secretions of the fungus cause the axillary buds to actively grow, which leads to the formation of dense clusters of short and thin shoots, often branched. Such shoots almost never bear fruit, the leaves on them are small, irregular shape, rapidly falling.

gray yellow tinder fungus
mistletoe
Large rattle

From the flower department

During the flowering period, they usually form a spike-shaped inflorescence, where a huge number of small, like dust, seeds are formed that can remain viable for a long time. Seeds are dispersed by the wind over considerable distances and germinate only on the roots of suitable host plants under the action of root exudates and at a certain soil acidity.

To combat dodder, strict plant quarantine, thorough cleaning of sowing seeds, mowing of affected forage grasses and burning stubble, spraying with various chemicals (lime-sulfur decoctions, solutions of iron sulfate and ammonium nitrate) and etc.

Broomrapes grow on the root systems of deciduous tree species, most often birch.

Mistletoe forms dense spherical bushes with numerous branched shoots and thick oblong-oval green leaves. It is capable of photosynthesis, but cannot exist independently, as it is completely cut off from the soil and feeds on the juices of the host plant with the help of haustoria and root-like rhizoids spreading under the bark. The seeds are covered with viscin (very sticky mucus) and are easily transferred to neighboring trees, sticking to the legs and feathers of birds.