Wing-like projections on fruits or seeds are widespread in representatives of a wide variety of angiosperm families, as well as in many conifers.
The “wings” themselves are extremely diverse both in origin and structure: in size, outline, position relative to the rudiment, etc.
Wing-shaped appendages on seeds in angiosperms are outgrowths of the seed coat, most often its overgrown epidermal tissue. The skeleton of such outgrowths is either veins extending from the main vascular bundle of the seed stalk, or thickened radial walls of epidermal cells.
The wing on conifer seeds is formed by the tissue of the fertile scales of the cone, and not by the seed coat. Obviously, in connection with this, the wings of coniferous seeds easily fall off.
The wings on the fruit are usually outgrowths of the walls of the ovary. They are strengthened by more or less abundantly branching vascular bundles of the pericarp walls. In the paleotropical family Diptera, the wings are overgrown sepals, tightly enveloping single-seeded, indehiscent fruits.
Often, wing-shaped appendages are formed by bracts, tepals and other organs. All these formations will be discussed below.
The flight properties of the rudiments equipped with wing-shaped appendages are determined by many characteristics of these appendages. First of all, the size of the wing relative to the size of the fruit or seed itself matters. The larger and more massive the wing, the more developed its frame should be. However, the skeleton of the wing in its different parts is often developed unequally, which shifts the center of gravity of the entire projectile and determines the position of the rudiment during flight. Secondly, the nature of the flight of the rudiment will depend on the position of its center of gravity relative to the geometric center. The outline of the wing and its symmetry are also of significant importance. The morphological and anatomical structure of the wing ultimately determines the duration of the fall of the rudiment, the nature of its flight (soaring, screw, etc.) under different atmospheric conditions and, finally, the flight range.
Let us note that the structures of wing-like formations on fruits and seeds served as models for the design of flying machines, gliders, propellers, etc. Some wings of fruits and seeds also show a striking resemblance to the wings of insects.
We give the classification of wing-shaped appendages on fruits and seeds mainly according to Ulbrich (1928), only with some modifications. New designations for the various categories are given, since the names proposed by Ulbrich do not reflect the morphological structure of the primordia.
Disc-shaped fruits and seeds
In this group of rudiments the center of gravity more or less coincides with the geometric center. Fruits and seeds of this type are most often flat, more or less evenly surrounded by a wing-shaped border.
The entire rudiment, together with the appendage, has a rounded outline. The edges of the pterygoid process are thin; the wing veins are more developed near the center or longitudinal axis of the bud.
Well-known representatives of this group of fruits are the lionfish of various types of elm and the very similar fruits of Ptelea trifolia from the Rutaceae family. A more original fruit develops in the dwarf tree - a thorny shrub from the buckthorn family, a resident of the rocky slopes of the Crimea and the Caucasus. The fruits of the keep-tree are a dry drupe with a wide wing-shaped border. Unlike typical lionfish, they are not flat in longitudinal section: in the center their thickness reaches 8 mm, while the edge of the wing hardly exceeds 0.1 mm in thickness. The stone containing the seed is very hard, almost spherical. On all sides it is surrounded by spongy suberized mesocarp tissue, which gradually becomes thinner and forms a winged border of the fruit. The plane of the wing is perpendicular to the longitudinal axis of the fruit. Among herbaceous plants, quinoa coinifera has fruits of this type. Here, the wings of the fruit are formed by bracts, which grow strongly, grow together along the edges and form a wide wing-like border around the fruit.
Disc-shaped winged seeds are found in some liliaceae (tulips, lilies) and gentianaceae. This category also includes the seeds of toadflax and toadflax. In the last two species, the wing-shaped border is poorly developed relative to the size of the seed. This especially applies to rattles.
When there is no wind, the disc-shaped fruits, falling from a considerable height, descend in a slow gliding flight, while describing large curves. When the wind blows, they are carried along very different trajectories, so it is difficult to establish any patterns. However, rotation of the fetus around its axis, as a rule, does not occur.
Rudiments with unequal wings
The rudiments of this category are close to discoid. Their center of gravity most often lies not in the geometric center, but on the main axis of the rudiment, but eccentrically. The main difference between these primordia and discoid primordia is that the outline of the primordium, together with the wing, has a varied, but not round, shape. Here you can find oval, semicircular, crescent-shaped, more or less rectangular and even lanceolate shapes. In this case, the width of the wing-shaped edge of the rudiment in different directions will naturally not be the same.
The nature of the fall and flight of these rudiments is somewhat different and is determined by the characteristics of the wing-shaped outgrowths. The fruits of birch and alder, as well as the disc-shaped primordia, are characterized by gliding flight without rotation of the primordium. The plane of the wing when the fruit falls lies more or less horizontally. The fruits of birch and the fruits of alder, which are very close to them, can only conditionally be classified as primordia with unequal wings, since their wings sitting on the sides are the same, but these primordia are difficult to classify as disc-shaped, in which the wing borders the primordium more or less evenly with all sides. Naturally, all the variety of forms that exist in nature cannot be accurately placed within the framework of any classification.
The wing of the ailanthus fruit is tall and lanceolate. The single-seeded nest of the fruit is placed in the middle of the wing. The plane of the wing, and especially its lower end, is somewhat S-shaped. As a result, when the fruit falls, even in calm air, and even more so in the wind, a rotational motion occurs around an axis perpendicular to the plane of the wing. The latter turns out to be inclined when the rudiment falls. The rotational movement of the rudiment lengthens its trajectory and the time of fall, and the inclined position of the wing creates a gliding angle, due to which the rudiments are carried away by the wind.
Large, very flat, wide-winged seeds of amaryllis, grown in our country as a houseplant, have an irregularly kidney-shaped outline. The seed itself lies in the middle of the wing and is shifted towards its convex edge. When amaryllis seeds fall from a certain height, you can often observe their very rapid rotation in a horizontal plane.
We were not able to observe the flight of other rudiments of this category. According to Dingler, flat disc-shaped seeds and fruits do not have a stable equilibrium. The path of the center of gravity of these rudiments when falling in calm air is a wavy line.
Rudiments with one-sided asymmetrical wing
Unlike the previous two, in this group of rudiments the seed, and, consequently, the center of gravity, is not located in the middle of the wing, but is shifted to one of its ends. The wing is elongated, asymmetrical. One longitudinal edge of it is straight or only slightly concave, while the other edge is strongly convex, almost rounded. At the same time, the straight edge of the wing is noticeably thickened and strengthened by the vascular-fibrous bundle and mechanical fibers passing through it. A dense network of veins extends from the marginal bundle into the wing, directed towards the convex thin edge of the wing. This venation is characteristic of lionfish of different types of maple. The wing-like appendages on the seeds of pine and many other conifers, similar in general outline to the wings of maple fruits, are much thinner and less strengthened, since they do not have a vascular skeleton. But even in conifers, the straight edge of the wing is somewhat thicker than the convex one. The winged beans of some legumes should also be included in the rudiments of this type, although both edges of the wing remain thin.
The most typical structure of a one-sided asymmetrical wing is expressed in maples. Falling even from a small height in calm air, maple lionfish begin a very fast rotational movement.
The aerodynamic properties of the fetus are determined, on the one hand, by a sharp shift towards the center of gravity of the entire formation, and on the other, by the unequal outlines and system of strengthening of the various edges of the wing.
A single maple lionfish is most closely comparable to a propeller. The thick, straight edge of the wing always faces forward in the direction of movement, so this edge of the wing represents the attack edge, and the other thin, rounded edge is the flow edge. Due to the uneven thickening of the edges of the wing, its leading edge tilts at a certain angle to the horizontal plane. In other words, an angle of attack is created, which increases the thrust force acting on the lionfish during flight.
Due to the shift in the center of gravity, not only the transverse, but also the longitudinal axis of the wing forms an angle with the horizontal plane. As a result of this position of the wing plane, a helical rotational movement of the rudiment occurs, which increases the duration and, in the case of wind, the flight range.
Rudiments with a one-sided symmetrical wing
As the designation of this group of rudiments shows, their difference from the previous ones is only that the wing of the rudiment is symmetrical, although one-sided relative to the position of the seed and the center of gravity. The wing also has an elongated shape, but the outlines of its sides are the same. Both edges of the wing are thin along the entire length. The wing is thickened and strengthened by a vein along the median longitudinal line.
The rudiments of this type are the fruits of ash and tulip trees. When free falling from a height, such fruits not only describe a helical line, but also wrap around their longitudinal axis.
Fruits with various wing-like appendages
The four categories of primordia described here, of course, do not exhaust the entire variety of wing-like outgrowths on fruits. We have already briefly mentioned the peculiar wing-shaped sepals surrounding the fruits of Diptera. Representatives of tropical flora also have more original fruits. Thus, Ulbrich describes the fruits of one of the species of cavanillesia from the baobab family, an inhabitant of the tropical forests of the Upper Amazon. Its fruits are indehiscent, about 25 cm long, and bear on their surface 5 large semicircular paper-thin wings. The width of the wings reaches 8-9 cm. They are penetrated by conductive bundles extending from the edges of the fruit. Ulbrich calls this type of fruit a rotating cylinder.
The shrub of our Central Asian sandy deserts - juzgun leafless az of the buckwheat family - produces fruits reminiscent of the cavanillesia fruits described here. True, juzgun has significantly smaller fruits (15 mm), but they also bear 5 wide wing-like outgrowths. The wings are not located strictly in meridional planes, but are somewhat curved. Fruits of this kind are well adapted to be quickly transported by the wind along the surface of the sand. They move so easily and quickly from place to place that sand does not have time to cover them. This movement of primordia with the help of wind along the surface of the earth can be called anemogeochory.
In many species of sorrel, the three inner tepals grow greatly at the time of fruiting and surround the fruit in the form of a wide-winged “box”, without, however, growing to it. In cases where the peduncle has an articulation, the fruits fall off the peduncle along with the winged perianth, which serves as an anemochorous device. More or less effectively, it can serve for anemogeochory, i.e., for moving fruits along the ground, provided that the species grows in areas with sparse grass cover. For airborne transport, the wing-shaped perianths of sorrel can only be considered as a hemianemochorous adaptation.
The fruits of many umbelliferous species are strongly compressed from the back, so that in cross section they are completely flat, while a wing-shaped border develops along the lateral ribs. This type of fruit is found in hogweed, gorichnik, parsnip and others. Sometimes the wing-shaped border does not develop on flat achenes, and not only along the lateral ribs, but also along the dorsal ribs. All these devices, based on their effectiveness, should be regarded as hemianemochoric. Thus, according to our observations, in the Siberian hogweed (stem height 126 cm), the bulk of the fruits, with an average wind and artificial shaking of the stem, flew 130 cm; single, most distant primordia were noted at a distance of 171 cm from the mother plant.
In many species of Solyanka, the fruits are surrounded by a wide wing-shaped border formed by tepals. At the top of the fruits of some teasel plants (scabiosa, etc.), the outer calyx grows and becomes leathery, forming a hard inverted parachute.
The aerodynamic properties of the various wing-shaped outgrowths considered here are, of course, very different. As Morduchai-Boltovskoy notes, the fruits of dipterous plants combine the principles of a parachute and a helicopter. Numerous wings extending from the fruit in meridional planes at different angles are capable of most fully using the energy of wind gusts.
The flat fruits of umbellifers with a wing-shaped border can be compared to a disk. Finally, hodgepodge fruits represent a transitional type from a parachute to a winged glider. They can be thought of as a Stesen parachute with raised wings that help dissipate air vortices more fully than conventional parachutes.
According to Mordukhai-Boltovsky, the rigid parachutes of fruits play the role not so much of parachutes as of bristles, with the help of which contact with the ground is reduced and lifting by a gust of wind is made easier. In other words, fruits of this type are best adapted to anemogeochory.
In some cases, rather wide wing-shaped outgrowths develop on the side walls of polyspermous dehiscent capsules (lily, dioscorea and others). Such outgrowths are usually interpreted as anemochoric devices, since the wind, striking the wing blades, sways the bolls more strongly and promotes seeding. In our opinion, such wing-like formations can only be considered pseudoanemochorous. If the seeds of these plant species do not possess any flight adaptations, then such plants should not be included in the category of anemochores.
To complete the characterization of wing-shaped anemochore formations, we need to focus on assessing their effectiveness. A wing of any structure as a flying device will operate most effectively if the winged rudiment falls from a considerable height. Therefore, obviously, rudiments with wing-like adaptations are characteristic mainly of tree species and lianas and are rare among herbs.
Wing-like projections on fruits or seeds of herbaceous plants are usually combined with ballistic adaptations in these species; this applies to toadflax and rattle from Noricaceae, to all types of Umbellaceae, to Liliaceae and Amaryllis with winged seeds, etc. In all these species, anemochory is only an additional way of dispersing the primordia, while the main role is played by ballistic adaptations. Only for high-stemmed ballistae, towering above the rest of the herbage, wings on fruits or seeds can significantly increase the dispersal range of the buds.
The efficiency of dispersal of anemochoric primordia of tree species will largely depend on the time of year and the duration of seeding. During the year, the nature of the wind changes (strength, gustyness, etc.), the foliage of the crowns, and in winter special conditions are created for the spread of germs along the snow crust.
In very few tree species, seeding occurs in early summer: elm, aspen, and willow. In other anemochores, the primordia disperse during autumn, winter and spring: in linden, maple, birch - in autumn at the end of leaf fall; for ash - from the beginning of autumn leaf fall until spring. In winter, about 50% of the ash fruit harvest falls on the snow. Some of them are covered with snow and remain near the mother plants, the other part is carried away by the wind along the crust.
Alder fruits fall off in winter. Infestation of spruce and pine occurs in March - April, and in pine later. The assumption of some foresters that pine seeds are spread mainly over snow crust is hardly fair. According to Alekseev, Molchanov and Shimanyuk, the bulk of pine seeds fly out on average on the 20th of May, when there is no longer snow cover.
The range of mass dispersal of winged buds of tree species is small: it is measured in tens of meters and, as a rule, does not exceed 100 m. This is confirmed by long-term experience of silvicultural practice. The usual width of cutting areas designed for natural forest regeneration is 100 m, i.e. approximately 4 times the height of the forest. Thus, the spread of seeds from each wall of the forest is carried out at a distance exceeding twice the height of the seed plants. The spread of seeds to the cutting area depends on their size and wingedness. As Nesterov points out, aspen and birch seeds abundantly fly into cutting areas even 1-2 km away. However, Molchanov’s observations on the restoration of concentrated cutting areas with such species as pine, spruce, birch and aspen showed that in 5 years an area up to 300 m wide from the forest wall was well restored. The area 350-450 m away from the forest wall was slightly restored, and even further away it was not restored at all.
With regard to pine, spruce and fir, various authors unanimously indicate that the seeds of these species are dispersed within 100 m. Thus, according to Alekseev, who observed the spread of pine in a forest aged 160-180 years with an average trunk height of 23 m, pine seeds fly away from the wall forests are predominantly no further than 50 m (20%); at 75 m no more than 11% of seeds are carried away and at 100 m - an insignificant amount. The same author shows that spruce carries away an average of 8.4% of the possible seeds further than 80 m. Molchanov (1949) gives approximately the same figures.
There are separate indications that, on snow crust, spruce seeds are carried by the wind 10 km, and pine seeds even 50 km. But even if these facts are reliable, then, of course, they relate only to single seeds, which can hardly ensure the spread of pine and spruce over such distances.
The natural distribution of ash and elm is limited to even shorter distances than that of conifers. Thus, according to observations in the Tellerman forestry, the appearance of self-seeding ash under the forest canopy is possible at a distance of 30-50 m from the source of seeds. Kolosova’s data on the distribution of birch bark in the Savalsky forestry indicate that by self-seeding this species spreads to 10-12 m.
In the same forestry, single specimens of elm undergrowth were noted at a distance of 100 m and 1 specimen of elm at a distance of 300 m from the seed plants. The same author noted a number of Tatarian maple specimens at a distance of 250 m from the seed source. Nesterov paints exactly the same picture of the distribution of tree species with winged rudiments. Species such as spruce, fir and linden settle in the Petrovskaya Forest Dacha only very gradually, directly around the seed specimens of these species. Over the course of 130-150 years, a spruce planting of 55-65 years old with an area of about a hectare appeared around the lonely spruce trees. Such a spruce island is surrounded by an “avant-garde” of settling young fir trees. Balsam fir naturally colonizes along the forest strip bordering the nursery. Natural renewal of the linden tree also occurs due to the seeds growing on the territory of the dacha, or due to the influx of buds from the park, 200-250 m away from the forest.
These are the specific facts of the settlement of tree species with anemochorous winged primordia.
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This luxurious tree, beautiful at any time of the year, is a true decoration of city gardens, parks and squares. In autumn, maple leaves acquire a wide variety of colors and shades: from the familiar yellow to deep crimson.
This tree, with its beauty, inspired world-famous artists to create paintings, and poets wrote poems about it. In this article, we invite you to learn a little more about this plant, which may be in your city. How to grow maple from seeds, and is it possible? How to care for it if you planted a tree on the territory of your country house?
Spreading
Under natural conditions, maple grows almost throughout the Northern Hemisphere. Twenty species of this plant are common in Russia, the most common of which are:
- Norway maple;
- field;
- Tatar;
- white.
Japanese maple is included in the Red Book of the Russian Federation.
Description
The genus Acer unites woody and shrubby plants of the Sapindaceae family. Widely represented in Europe, North America and Asia. The genus includes more than one hundred and fifty species, which mainly grow in the temperate zone; some of its representatives are found in Central Asia and the Mediterranean.
The tree grows up to thirty meters in height. The trunk is covered with gray-green bark with a network of lighter veins. The leaves are large, three-lobed, up to seventeen centimeters long. The edge of the leaf blade is finely toothed. The flowers are small and greenish in color. They have five oblong sepals and the same number of oval petals. There are eight pubescent stamens. The ovary is short and in male flowers underdeveloped. The peduncle is thin, about five millimeters long.
Maple: fruits and seeds
The fruit of this tree is the lionfish. This is an achene with a leathery, dry pericarp and a flat, wing-shaped fibrous outgrowth. With its help, the maple tree reproduces. The dispersal of seeds by wind is quite interesting: the lionfish moves amusingly through the air, writing spiral pirouettes, scattering over long distances and introducing itself into the composition of tree stands.
Seeds
What kind of seeds does maple have? They are completely naked, having a green, large, curled embryo. Maple seeds are slightly flattened in shape. They ripen at the very end of summer, and often remain on the tree throughout the winter. The seeds are covered with a thin skin. The tree bears fruit annually and abundantly; in Russia this occurs in September.
Growing maple from seeds
There are many types of maple in our country, so everyone can choose a suitable specimen even for a very modest-sized garden plot. It's nice to grow such a luxurious tree with your own hands. Moreover, it is not difficult to do this even for a beginner in gardening.
First of all, you need to decide what type of maple you want to grow. The thing is that not all varieties can be propagated by seeds - there are decorative forms that are propagated exclusively by grafting or cuttings.
For growing from seeds, the following are most often used:
- Ginnala maple;
- Tatar;
- green-skinned;
- holly.
Maple seeds collected in the fall or purchased in a store must be stratified. In other words, it is necessary to simulate under artificial conditions the transition of a plant from a state of winter dormancy to rapid growth. To do this, the seeds are kept at temperatures from +3 to +5 °C for 120 days. You can use a refrigerator or cellar for this. Maple seeds are stored in a small container, which is filled with wet sand.
Germination of seeds
In April or early May, seeds are planted for germination. They are transferred immediately to open ground. To make sprouts appear faster, you must first soak the maple seeds in hydrogen peroxide for three days. After this procedure, they are completely ready for planting. Now you need to choose a place for the tree.
Where to plant maple?
The area where you plan to grow the tree should be sunny or slightly shaded. It is desirable that the soil be loose and fertile, so first (before planting) the soil is dug up well and loosened so that it becomes homogeneous and fine-grained. Add a little humus, peat and sand to the garden soil.
Planting seeds
The seeds are planted to a depth of about four centimeters. If you do not plan to further transplant the seedlings, then the distance between plants should be at least two meters. You can plant seeds at a closer distance, the seedlings can be thinned out, and the strongest seedlings can be planted at a closer distance. After planting, the seeds are watered and the soil is kept moist.
Emergence of seedlings
The first shoots will appear approximately three weeks after planting. Maple germinates rather slowly, but when the seeds have sprouted, they need simple care: regular moderate watering, weeding the soil. In intense summer heat, shade young plants from the sun's rays. By autumn, your seedlings will already grow up to 40 cm, and in the first year - up to 80 cm.
Autumn planting
Sometimes maple seeds are planted in open ground in the fall. In this case, they remain in their natural environment all winter and germinate in the spring. With this method, seed germination is slightly lower due to strong and snowless winters, however, this method is considered the most natural.
Depending on the size of the seedlings, after one to three years they can be transplanted to a permanent place. To do this, you need to prepare holes measuring 50x50x70 cm. The composition of the soil is the same as when growing seeds. Before planting, add organic fertilizers (compost or humus) to the soil. Every year in the summer, apply complex fertilizers for perennial plants.
Maple is a magnificent and easy-to-care tree that has positive energy. In the shade of its dense crown you can relax in the summer, and in the fall you can admire the constantly changing colors and shades of foliage. Planting a maple is a long-term investment in the future of your garden or summer cottage. Maple will delight not only you, but also your children and grandchildren with its noble and sophisticated appearance.
Antonenko AndreyInfraorder: Apes (lat. Simiiformes) Scientific classification Without rank: Deuterostomes (Deuterostomia) Phylum: Chordata (Chordata) Subphylum: Vertebrata (Vertebrata) Infratype: Ghathostomata (Ghathostomata) Superclass: Tetrapoda (Tetrapoda) Class: Mammals (Mammalia) Subclass: Animals (Teria) Infraclass: Placentals (Eutheria) Superorder: Euarchontoglires Grandorder: Euarchonta Worldorder: Primatomorpha Order: Primates Suborder: Dry-nosed primates (Haplorhini) Infraorder: Simiiformes First order: Narrow-nosed monkeys (Catarrhini) Broad-nosed monkeys (Platyrrhini) Contents 1. General information about...
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In our city, one of the most common trees is ash. It grows everywhere! I love this tree very much: it produces amazing fruits - helicopters, which I use in various activities with children (these are hedgehog spines, dragonfly wings, etc.). But recently I noticed how these helicopters are growing: now they are so small and delicate! See for yourself!
And then I began to study articles about ash on the Internet. It turns out that there are several species of this tree. It’s true: there are two types of helicopters (at least in our city). There were no dry helicopters on this tree, only young ones, but everything is on the Internet! Here they are.
As a child, almost everyone liked to launch helicopters - maple seeds, which, spinning, slowly fall to the ground. The latter helps them spread over larger areas, because the grains slowly approaching the ground are carried further by the wind. How exactly rotation delays the fall of a seed has not yet been understood not only by children, but also by adults. Scientists from Wageningen University in the Netherlands and the University of California
Finally revealed the secret of the flight of maple leaves, and also found out what benefits this flight brings to the seeds.
Experiment with oil
Scientists chose for their research three types of maple and one hornbeam - the seeds of these trees, falling, rotate around their axis. To understand the aerodynamic processes that accompany the flight of seeds, the researchers created a model of each species 
seed, automatically rotating using an electric drive. The model was placed in a special tank with oil. The rotation speed and viscosity were chosen so that the oil flow created by the model seed was identical to that created by the seed in the air. Scientists added glass beads to the oil, which were illuminated by a laser. The process was filmed on a high-speed digital camera. This technique, called digital particle image velocimetry (DPIV), is often used to study air or fluid flows.
The scientists processed the footage and found that their model seeds, as they rotated, created a so-called leading edge vortex - a tornado-like air funnel above the center of gravity of the falling spinning seed. An area of low pressure is created inside this funnel, which means that due to the difference in pressure from above and below the seed, a lifting force arises, counteracting gravity and preventing the seed from falling for a long time.
Animal strength
This power is already known to scientists. It is what insects, bats and even hummingbirds use when they hover in front of a flower, collecting its nectar. It is the lift created by the vortices that cause the complex vibrations of the bumblebee's flexible wings that allows it to fly, although, according to legend, it should not. It turns out that in the process of evolution, not only different animals - insects, birds and mammals - came up with a convergent aerodynamic solution. Some plants have reached the same idea “with their own minds,” according to the authors of an article published in Science.
Scientists decided to test their model experiments on a real seed. It was impossible to place it in oil, so it was forced to fall in a vertical wind tunnel, in which the wind speed was brought into line with the speed of the falling seed. And to visualize the resulting flows and expected vortices, the pipe was filled with smoke. Videos taken in a tube with the participation of 30 different seeds confirmed the scientists’ assumption: vortices, previously attributed only to the wings of living organisms, are also created by the plant wing.
Why are they spinning?
Why does a tree try to spread its seeds as far as possible? It’s clear that there are too few resources under the parent tree for them to grow, and in distant lands there may be more chances to survive. But why the tree uses rotation is unclear. After all, there are alternative mechanisms, for example planning. However, the latter requires a large leaf area with low mass.
The scientists compared the ratio of fall time to wing loading—the weight per unit area of the wing—for self-rotating seeds and for gliding ones. They concluded that rotation was twice as effective at dispersing seeds. On average, rotating seeds have 5.5 times higher wing load than gliding seeds, but they fall faster by only 30%. Thus, plants that have evolved this interesting seed form can afford to spend energy on storing nutrients in the seed rather than growing its huge wing.
Scientists believe that their research will be of interest to everyone who was fond of tossing maple seeds in childhood, as well as biologists and evolutionists. Perhaps their work will also bring practical benefits in the creation of a rotating parachute or a microscopic helicopter with one wing. Similar developments already exist, but it wouldn’t hurt to pick up a few tricks from nature to improve them.
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