Perianth simple and double: structural features

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Perianth simple and double: structural features
Perianth simple and double: structural features
Anonim

A flower is one of the most amazing creations of nature. And from a biological point of view, this organ performs the most important function - it provides generative reproduction of plants. From our article you will learn about its structure, diversity and structure of a simple perianth.

What are generative organs

The flower is a modified shoot, which is limited in growth and shortened. Its main parts are four. These are the pedicel, receptacle, stamens and pistils. The first two parts are called sterile. This means that they do not participate in the process of sexual reproduction of plants. The pistil and stamen are the fertile parts. They contain sex cells. As a result of pollination and fertilization, a seed is formed, which is located inside the fruit. This is how sexual reproduction occurs in flowering plants. Thus, the generative organs include the flower, the seed, and the fruit. Their presence is typical only for representatives of the Angiosperms department.

Because a flower is a modified shoot, it has all the parts that are inherent in the above-ground parts of plants. So, the pedicel is an internode. On it they canleaflets are located, which are called bracts. In nature, sessile flowers are often found. They are attached directly to the stem.

The extended part of the pedicel is the receptacle. It can be flat, concave or convex. In plants that are pollinated by the wind, the flowers are usually dioecious. This means that they contain either stamens or pistils. Such flowers have an underdeveloped corolla, and in some cases are deprived of it. This makes the wind pollination process more efficient. If dioecious flowers are located on one individual, the plant is called monoecious. These include oak, birch, alder, aspen, sedge. In dioecious plants, same-sex flowers are on different individuals. These are willow, poplar, sea buckthorn, aspen, sorrel.

flower with simple perianth

Structure of the perianth

Let's consider the structure of the sterile part of the plant. This is a perianth - simple and double. It consists of a whisk and a cup. This structure is called double, or heterochlamyd. Its presence is a systematic feature. All plants of the Dicotyledonous class have a double perianth. For example, peas, apple tree, eggplant, aster, sunflower. In nature, most of these plants.

The composition of a simple or homochlamydous perianth includes either a corolla or a calyx. It is characteristic of monocot plants. It includes the family of Onions, Liliaceae, Cereals and others.

unopened flowers with a simple perianth

Whisk

This is the brightest part of the perianth. The collection is called a corolla.petals. It is much larger than a cup. The whisk is painted in different colors. Bright petals are necessary for the plant to attract insects. In wind-pollinated species, the corolla is inconspicuous or reduced.

The shape of the corolla is also quite diverse. For example, in legumes, the petals are morphologically different. The top one is the largest. There are two free petals on the sides, and the lower ones are partially fused. Outwardly, they look like a sail, a boat and oars, or a butterfly that has folded its wings. Therefore, the legume family is also called Moth.

In nightshade plants, all the petals fuse together, forming a tube with a throat. It ends with free teeth. The number and shape of the petals is also a systematic feature. So, representatives of the Rosaceae family have five of them, Cruciferous - four. And in the Astrovs, the inflorescence includes up to one and a half thousand small petals.

tulip flowers without sepals

Cup

Another part of the perianth is a set of sepals. Their main function is protective. It is carried out during the formation of the bud. At this time, the sepals completely cover the flower. In an adult plant, the calyx is the photosynthetic part. Along with leaves, it additionally provides plants with organic matter.

Sepals consist of the main tissue - the parenchyma, in which vascular bundles are located. Outside is the integumentary tissue - the epidermis. The sepals are colored green. Being derivatives of bracts, simple shape and small size,outwardly, they resemble vegetative ones.

According to the features of the structure, a separate and joint-leaved calyx is distinguished. In the first case, the sepals are attached freely and are located at a certain distance from each other. Tobacco and nightshade have a calyx leaf. Its components are the tube, teeth and lobes, the number of which is equal to the number of sepals. Cups of this type can be funnel-shaped, bell-shaped or tubular. In sage and skullcap, this part of the perianth consists of two unequal parts. In this case, it is called two-lip. Sepals of mallow and strawberry form two circles. This feature provides additional protection during bud formation.

In some plants, the sepals fall off or fold back during the blooming of the flower. And in representatives of some families, they are modified. In this case, the cup performs an additional function - it spreads the seeds. For example, in yasnotkovye it turns into a box, and in aster - into a crest.

Not always the cup is green. Examples of such plants are larkspur and hellebore. Their corolla is very reduced. Therefore, its function is performed by a bright perianth.

lily flower without sepals

What is a simple perianth in biology

The main feature underlying the classification of this part of the flower is the presence of two main parts - the corolla and the calyx. Depending on this, a complex and simple perianth is distinguished. In the first case, it is represented by both petals and sepals. In most cases, the structuresimple perianth is represented only by the corolla. Let's consider its structure using specific examples.

sunflower flower pollinated by bees

Which flowers have a simple perianth

The structure and number of flower parts is an important systematic feature. So, a simple perianth is a characteristic feature of the class Monocots. A striking example of such plants are the tulip and lily. Their simple perianth is nothing more than a large and bright corolla. Such flowers easily attract the attention of insects. This is also facilitated by the pleasant aroma of flowers. The fact is that the integumentary tissue of the petals, which is called the epidermis, contains essential oils.

So, in our article we got acquainted with such a concept as a simple and double perianth. In the first case, this structure consists of a calyx or corolla. Flowers with a complex perianth have both of these parts developed.

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