The flowering department is a large class of plants that form special shortened modified shoots - flowers in the course of their life. Unlike vegetative organs (roots, leaves and shoots), they, together with seeds and fruits, perform the most important generative functions. In this article, we will look at several serious topics, including the structure of a flower and the function of its main parts. We will discuss what flowers are, how they are classified and how they differ from each other.
Biology: flowers. The structure and functions of their stem part
In nature, there is a great variety of flowers that differ from each other in structure, color and size. Each of them is beautiful in its own way. Biologists consider the flower as a complex organ necessary for seed reproduction. In general, heconsists of three parts:
- stem (receptacle, pedicel);
- leafy (petals, sepals);
- generative (pistil(s), stamens).
The flower is attached to the top of the shoot with the help of a pedicel - a special elongated organoid, a continuation of the stem.
In the flowers of some plants, for example, sunflower, corn, verbena, plantain, clover, the pedicels are almost invisible due to their strong shortening. In the nodes of the receptacle - the upper, wider part of the pedicel - there are a calyx, stamens, corolla and pistils (one or more). The receptacle can be of different sizes and has a variety of shapes - convex (raspberry), flat (chamomile), concave (rose hip, bird cherry) or elongated (gravilate).
Flower leaf
The calyx is an organ consisting of modified leaves (sepals). Its main function is to protect the inside of the flower until the bud opens. The calyx can be either sporifolia (if the sepals are separated from each other) or sympetifolia (if they are fused). The corolla is the brightest, most visible part of the flower. It consists of petals, which in flowers of different plants can vary greatly in shape (tubular, bell-shaped, wheel-shaped, funnel-shaped, etc.) and color. The main functions of the corolla are to protect the pistil and stamens from adverse environmental conditions and to attract pollinating insects. Whisk andthe calyx is made up of the integument of the flower, which is called the perianth. It can be simple, consisting of similar free or fused leaflets, or complex, clearly differentiated into a corolla and calyx, which differ significantly from each other in size and color. A simple perianth is found in lily of the valley and a tulip, and a complex perianth is found in a bell, carnation, petunia and cherry. There are flowers completely devoid of the mentioned element, they are called naked (willow, ash). Now you know what flowers are in terms of the structure of the corolla and calyx. Next, we will talk about the reproductive organs of the flower.
Generative part of the flower
Stamens and pistils are the most important parts of a flower. They are at its center. The stamens are arranged in one or more circles near the inner edge of the perianth and consist of a filament and anther, in which pollen is produced. The pistil consists of 3 parts: style, stigma and ovary. The latter contains the ovules, from which the seed appears after fertilization. Most plants have one pistil and several stamens - from three to a hundred. They are called bisexual. Some flowers, such as cannes, have only one stamen. There are plants that have either stamens or pistils. They are called same-sex - staminate or pistillate. Some flowers, such as cornflower and sunflower, do not have either organ at all. That is why they are called asexual. What are the flowers in this case? Plant species that simultaneously haveboth staminate and pistillate flowers are called monoecious. Representatives of this group are pumpkin, oak, cucumber, corn. If the male and female flowers are on different individuals (copies), the plants are called dioecious. Examples of these are willow, poplar, sea buckthorn.
Variety of colors
Despite the fact that in different plant species the modified shoots that perform generative functions have a similar structure, outwardly they can vary greatly. Their sizes can vary from a millimeter (for duckweeds) to one meter in diameter. One of the most interesting representatives of the flora is the tropical rafflesia. It has the largest flowers in the world, which emit a repulsive smell of rotting meat. Other plants, such as garden jasmine, wild rose, lily of the valley, exude a pleasant aroma. This delicate, delightful smell is due to special essential oils, which are formed in the cells of the epidermal layer of the petals and perianth. The flowers of many plants are endowed with special beauty and give people aesthetic pleasure. Roses and orchids are among the most beautiful flowers.
Petal coloring
Let's look at what flowers are by color. The shade of their petals is determined not only by chromoplasts, but also by special coloring substances - pigments of cell sap. For example, anthocyanin determines the pink, red, blue or purple color of the corolla, anthofein - brown, carotenoids - yellow, red and orange, etc. Interestingly, the color of the petals can changeduring the day - depending on the acidity of the cell sap. For example, the flowers of the Victoria amazonica plant change color from snow white to pink and then to red.
The white color of the petals (for example, in cherry, water lily, apple tree) is determined by the absence of pigments and the reflection of light rays. Are there black flowers? No, the petals do not have such a pigment. Dark coloring is a rich dark purple or deep maroon hues.
Wildflowers
About half a million different species of forest and field plants are known. But only 290 of them have been described and given their name. Since ancient times, wild flowers (the photo shows their diversity) have been used to make medicines. And no wonder, because many of them have healing properties. The most prominent representatives are: cornflower, chamomile, poppy, bluebells, dandelion, violet, forget-me-nots. Cornflowers are extremely beautiful flowers of bright blue color. Often they grow in crops of wheat. Field poppies stand out for their rich red, "fiery" petals. They are found along roadsides, in wastelands, but are especially common in the steppes. Field chamomile has beautiful flowers with a yellow head and white petals. Pharmacy chamomile is widely used in the treatment of many diseases, including the treatment of the digestive tract, liver, throat and mouth.
Forest flowers. What color are snowdrops?
The most famousflowers growing in the forest are anemone, St. John's wort, lilies of the valley, snowdrops, common sorrel, etc. Their beauty leaves no one indifferent. But the most tender of all the variety of the forest flower kingdom is the snowdrop. He first appears on the thawed patches, right from under the melting snow, and symbolizes the onset of spring. Do you know what color snowdrops are?
Most often these delicate primroses have white bell-shaped petals. But there are also pale blue, and even blue ones. The genus of snowdrops includes about two dozen species, the most famous of which are snow-white snowdrop, Elvis snowdrop, Caucasian snowdrop, etc. They like to grow in partial shade, under the canopy of shrubs and trees.
One of the most valuable forest plants is St. John's wort. You can recognize it by its branched stem and oblong-ovate leaves with a smooth surface. The flowers of this herbaceous perennial are bright yellow. St. John's wort is used in medicine as an anti-inflammatory, antimicrobial and hemostatic agent.
Beautiful garden flowers
Garden flowers are a large group of ornamental plants that are designed to decorate our lives and ennoble summer cottages and household plots. They can be classified according to some parameters. For example, garden flowers are often divided into three subgroups - annuals, biennials and perennials.
Themselves unpretentious and inat the same time, pansies, marigolds (calendula), alyssum, nasturtium are considered bright and beautiful annuals. Perennials are decorative flowers that retain their excellent properties for several years. They are ideal for any garden, and do not require an annual transplant and serious maintenance. What are the flowers? The names of the most famous perennials are as follows: astilbe, rose, peony, bergenia, daylily, lychnis, crocus, narcissus, tulip, etc. Daisies, violas, Turkish cloves, foxglove, mallow, etc. are considered the most famous biennial crops.
