world of nature is unique and diverse unthinkable.Every year scientists make more and more new discoveries that reveal to us the extraordinary prospect of studying the world around us.But quite familiar living organisms, about which one knows since time immemorial, is still able to surprise.Take, for example, lichens.They are simple, but especially their ability to live very unusual.
you know how to feed on lichens?It really is a unique process which is described in detail.
Difficulties knowledge
Generally, they are rather more difficult to study because they represent a symbiosis of very different organisms.Each lichen symbiosis formed autotrophic heterotrophic algae and fungus.It is understood that first have to study biochemistry and livelihoods each organism individually.This method of studying their physiology gives a lot of mistakes and errors, and because scientists have a lot of questions, not all of them have answers.However, researchers still managed to identify common patterns.
internal structure
In general, the whole body of lichen - a massive intertwining fungal hyphae, which are located inside the colony autotrophic algae.Today, the science of the following types of lichens:
- Gomeomernye species (Collema).Cells photobiont colonies (algae) in a chaotic manner scattered throughout the body.
- heteromeric (Peltigera canina).A cross section can clearly see the layers of Tal (hyphae) and algae.
Most lichens exist, the structure of which is based on the last principle.In this case, the entire top layer is formed particularly dense tangle of mushroom tissue, which protects the body from the negative effects of lichen environment.In addition, the fungus prevents too fast drying (but it helps not always).
The next layer is a colony of autotrophic algae.In the center is the core of the lichen, which is a tight strand of intertwined hyphae and fungal colonies autotrophs.This "bar" dual function: on the one hand, lichen stores in the core water.On the other - a kind of skeleton of the body.In the lower part there are riziny.It's kind of attachment with which the lichen clings to the substrate.It should be remembered that a complete set is not found in all species.
Some species of lichens (tsianolishayniki) characterized by the fact that in their structure are highly localized colonies tsianovodorosley.These kinds of layering is particularly well expressed.Since lichens feed?The answer to this question is directly related to the peculiarities of the process of photosynthesis in them.
about the process of photosynthesis
There are thousands of studies that are devoted to the peculiarities of these symbiotic photosynthetic organisms.Since about 10-15% of the volume occupied by algae, which gives them almost all nutrients, there are many questions about the intensity of the process.Oddly enough, but simple measurements clearly showed that the intensity of photosynthesis in lichens is much lower when compared to autotrophic higher plants.So, if the analogy with ordinary potatoes ratio is 1:16.
But how to explain quite comfortable livelihoods in such spartan conditions?In general, there is nothing particularly complicated about it.The fact that the autotrophic higher plant organisms most of his life, "awake", whereas lichens in some places almost the entire year are in half-dried state, in suspended animation.Of course, it is quite meager enough nutrients to sustain life.Here's how
eat lichens.Grade 7 school of biological orientation can explore this subject in more detail, but in this case, the answers to many important questions about the standard educational program does not.For example, when the formation of organic substances for food slower, and when - somewhat faster?
What determines the intensity of photosynthesis in lichens?
should be noted that the intensity of this process depends on a broad array of factors.It is also important that the chloroplasts, being covered with a dense layer of hyphae, receive much less light than those in higher education autotrophic plants and even algae.In principle, this difference is not so significant.
should be aware that the maximum value of photosynthesis observed at light within 4000-23000 lx.This can be found in the main habitats of lichens: tundra, forest, bright northern forests.In those areas where the light intensity is much higher in the body of a symbiotic organism begins intensive development of dark organic pigment (parietina), as well as specific only lichen substances (atranorina, for example).
obtained as a result of photosynthesis, organic substances are completely analogous to those of the higher plants.They also are used in food applications.Here's how to feed on lichens.7 class of secondary school studies the processes of their life rather superficially, even though it is a big subject, and extremely interesting.We bring you the advanced information that you may find not only interesting, but also useful.
Breathing
easy to guess that the development of nutrients depends on the breathing.In contrast to photosynthesis in lichens is intense: 0.2-2.0 mg SO₂ per hour highlights just one gram of symbiotic organism.If you carefully read the information in the upper part of the article, you probably realized that about 85-90% of the weight falls on the weight of the lichen mikobionta.Simply put, the oxygen it needs more of the mushroom instead of autotrophic algae.Since eating lichens normally not very regularly (the reason - severe climatic conditions), much of the nutrients stored in their tissues.
like photosynthesis, respiration process depends on the percentage of water.
should know that the minimum level of breathing, which is necessary to obtain a certain amount of energy from nutrients, lichen retains almost in all circumstances (suitable for life, of course).This process is possible under the following temperature range: -15 to +30, +50 ° C.However, the optimum temperature ranges from +15 to +20 ° C.With the cooling begins to dominate the use of oxygen.And at elevated temperatures of over 35 degrees, both of approximately equal.
A case where the lichen (photo of this species has in the article), brought in one of the Moscow museums expedition even the Royal Archaeological Society, quietly regained their livelihoods by being placed one of the employees in a flower pot with a slightly damp ground.But by the time he was about 90 years old I was in a completely dry, closed box for exhibits and most of the time was deprived of even the world!
Not surprisingly, these organisms so interested in modern biology.Lichens are certainly still many secrets, the disclosure of which may significantly spur the development of medicine.
Scientists have shown that the basic principles of breathing lichens are subject to the same laws as in the case of autotrophic higher plants.But there are differences, the main one being slightly different priority between the absorption of oxygen and release carbon dioxide.Moreover, they are resistant to phenomenally drying, low and high temperatures.No wonder the mosses and lichens can grow even in the Arctic.
temperature regime is most favorable for photosynthesis in lichens temperature range from +10 to +25 degrees Celsius.But the ability to absorb carbon dioxide they have saved up to -25 degrees.This is a very remarkable feature of lichens, which distinguishes them from higher plants and even algae.When the temperature is -5 to -10 degrees the intensity of assimilation of carbon dioxide almost more than in more comfortable conditions.In many plants, in this case formed in the intercellular space of the ice, which simply breaks the cell.
In contrast, the lichens on trees whose trunks are literally tearing the harsh northern climate (hard frost), thrive upon the occurrence of the warm season.
Features water exchange
researchers concluded that lichens have a particular, very specific type of water exchange.The fact that water in their body lies in the space between the strong hyphae.When it freezes, any harm that does not work, and the process of photosynthesis and nutrition continues to occur.However, when the temperature rises to 35 degrees Celsius or more, the process of photosynthesis is almost stopped, which is fundamentally different from the lichen plant.
amount of water that will be enough for normal life depends on the family.So, bushy lichens capable of photosynthesis and produce organic substances to supply almost the complete dehydration.The thicker the body, the more it can accumulate moisture, the less it evaporates.
This is particularly important for lichens, since in most cases they grow in very difficult conditions when a more or less regular flow of water is not completely guaranteed.In such circumstances, any plant would have died.Lichen also feels good even in these deserts and the Arctic.
Regulation liquid exchange
can understand that the regulatory function of water metabolism in these organisms arranged in a completely different way than in higher plants.Since they have virtually no specialized systems for this purpose.For example, uptake of water from them is extremely fast, but at the expense of its ordinary absorption throughout the body surface.You can hold a simple experiment: pour on the table a small amount of water and place on a piece of cloth or a puddle of toilet paper.
As you can see, water is instantly absorbed, since the structure of the paper has good absorbency.The same thing happens in the case of lichens.So, we have considered the episode of the long ago dried up a copy of which was once brought the expedition.When the employee put the lichen in a flower pot, he just instantly absorbed a volume of liquid, which was enough for him to restore life.
Some bushy lichens are able to absorb a huge amount of liquid, the weight of which is up to 300% of their own.Others types (kollemy, leptogiumy) thus increasing in size by 400-3900%!As for the minimum water content, it is about 2% by weight of dry matter of lichen.This lichen (photo can be found in this article) in appearance quite similar to a living organism.
The rate of return of water
As is the case with toilet paper, giving the water the body of a symbiotic organism rather quickly.Just one hour of lichen that has just absorbed almost a liter of fluid can dry to a brittle state.Thus, the "productivity" of these organisms are extremely cyclical: development of trophic substances can fundamentally change not only during the season, but for one or two hours!
In recent years, scientists have discovered that some species of lichens that live in the tundra (Evernia prunastri), may well use just "crumbs" of sunlight, occasionally breaking through the layer of snow.Simply put, they have photosynthesis does not end even in winter.
Reproduction lichens
addition, especially lichens are available immediately three methods of reproduction:
- vegetatively.
- floors.
- Sexless.
Mushroom, ie mikobiont can multiply in every way, while seaweed is able only to vegetative division.Fungal spores are in special bags.Askomitsetnye lichens for the breeding process uses two main groups of fruiting bodies: apothecia and perithecia.Their characteristics are as follows:
- Apothecia is the usual round shape bed.On it are bags that are placed in the gaps between conventional, non endings of hyphae.This layer is called openly located gimeniumom.
- Perithecia similar to the almost completely closed structure of spherical shape.Spores are released through the holes, which are arranged on the surface of the fruit sector.
Some species can also form asexual spores piknospory (piknokonidii).The place of their formation are Pycnidia.This spherical sacs or more pyriform which are highly hyphae.Pycnidia easy to recognize, because they look like black dots arranged on a bed.
When disputes wake up, they are suitable rapidly give rise to new gifam forming a new body of lichen.They (hyphae) can also penetrate into the cells of autotrophic algae, followed by the formation of a new organism actually ends.
value
general, mosses and lichens are of paramount importance.In the tundra and arctic desert them - often the only autotrophic organisms that can accumulate nutritious organic substances in extremely adverse conditions.Simply put, these organisms are a food source for the few herbivores that can live in such harsh places.In addition, only lichens on trees even in our climate can often survive the winter, for example, elk and roe deer.
