Flower Petal: Why Are They So Colorful?

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Flower petal 6

Flowers have many different sizes and shapes, and there are many variations in color, number of parts of the flower, and the arrangements of these parts. Though there exists a great diversity of flower types, all flowers have some common structural elements. A typical flower can be categorized into four sets based on function and appearance and function: sepals, petals, stamens, and pistils. Flower petal adds to a flower’s beauty and are the primary pollinator attraction.

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Here we discuss few interesting facts about flower petal and what is the importance of their vibrant color.

What are Flower Petal

A petal is a colored part of a flower. Petals are made of cellulose besides other organic matter. They are generally bright in color and scent. They often bring birds and insects to pollinate the flowers. The petals are modified leaves that surround the reproductive parts of flowers. All the petals of a flower together are called the corolla.

The petals and sepals are lowermost on the shoot, toward the sides of the flower. The pistil and stamens are at the tip of the shoot on the inside. While petals and sepals and petals are easy to see, stamens and pistils are often visible only when the flower is closely examined.

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Petals lie above the sepals of the flower. Although flattened like the sepal, each petal is generally colored and soft. Usually, the number of petals in flowers will be the same as that of sepals. If the sepals of a flower are joined together, then its petals are separate and not merged. The stamens inside the petals are composed of a small anther and a thread-like filament that connects anther with the rest of the flower. However, not all flowers have sepals, petals, stamens, and pistils.     

Importance of Flower Petal

The evolution of flowers and the role of petals have been studied from the 18th century to the present day. They play a significant role in pollination. The most common types of pollination are:

  1. Wind pollination is where the flowers are small and dull, with little or no scent and often no petals. They produce large amounts of pollen grains scattered all around by the wind.
  2. Insect pollination is where the flowers show well in the ultraviolet range and often have honeyguides.
  3. Bird pollination requires large, colorful flowers with nectar.

Petals of flowers are modified leaves that surround the reproductive parts of flowers. They are often unusually shaped and brightly colored to attract pollinators. All the petals of a flower are collectively called the corolla. They are usually accompanied by another set of modified leaves called sepals that collectively form the calyx and lie beneath the corolla.

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The corolla and calyx comprise the non-reproductive portion of a flower called perianth. When the sepals and the petals of a flower are difficult to differentiate, they are collectively called tepals. Aloe is one example of a plant in which the term tepal is appropriate, including genera such as Aloe.

Conversely, genera such as Phaseolus and Rosa have well-distinguished petals and sepals. When the undifferentiated sepals look like petals, they are referred to as petaloid, as in orders of monocots, petaloid monocots with brightly colored sepals. Although the petals are usually the most conspicuous parts of animal-pollinated and wind-pollinated species, such grasses either have tiny petals or lack them entirely.

Petals and Corolla

The collection of all petals in flowers is known as the corolla. The role of corolla in plant evolution has been studied since Charles Darwin postulated a theory of the origin of elongated corolla and corolla tubes.

  • A corolla of separate petals, without fusion of individual segments, is apopetalous. 
  • When the petals are free from one another in the corolla, the plant is polypetalous or choripetalous. 
  • When the petals are at least partially fused, it is gamopetalous or sympetalous. 
  • In the case of fused tepals, the term is syntepalous. The corolla in some plants forms a tube.

Petal often consists of two parts: the upper, broad part, similar to the leaf blade, also called the blade, and the narrow lower part, identical to the leaf petiole, called the claw, separated from each other at the limb. Claws are developed in the petals of some flowers of the family Brassicaceae, such as Erysimum cheiri.

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The inception and further development of petals show a great variety of patterns. Petals of different species of plants vary significantly in color or color pattern, both in visible light and ultraviolet. Such practices often function as pollinators’ guides and are known as nectar, pollen, and floral guides.

Significance of Flower Petal in Pollination

Pollination is one of the essential steps in the sexual reproduction of higher plants. The male organs of the hermaphroditic flowers or the male flowers produce the pollen grains. Pollen can not move on its own, requiring animal or wind pollinators to disperse the pollen to the stigma of the same or nearby flowers. However, pollinators are selective in selecting the flowers they choose to pollinate. This develops competition between flowers.

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Consequently, the flowers provide incentives to appeal the pollinators. Unless the flower self-pollinates or is involved in wind pollination. Petals play a significant role in competing to attract pollinators to carry out pollination. Subsequently, pollination dispersal could occur, and the survival of many species of flowers could prolong.

Flower Petal And Their Feature

Petals protect some parts of the flower and attract or repel specific pollinators. Petals have several functions and purposes depending on the type of plant. 

Function

This is where the flower petals are positioned on the corolla; e.g., the buttercup has shiny yellow flower petals. Pollinators can determine specific flowers they wish to pollinate. Flowers draw pollinators using petals as incentives and set up a mutual relationship. The pollinators will never forget to guard and pollinate these flowers.

Scent

The petals could produce different odors to allure desirable pollinators or repel undesirable pollinators. Some flowers will also mimic the scents produced by materials, such as decaying meat to attract pollinators.

Color

Several color traits are used by different petals that could attract pollinators with poor smelling abilities or that only come out at certain times of the day. Some flowers can change the color of their flower petal as a signal to pollinators to approach or keep away.

Shape and size

Moreover, the shape and size of the flower/petals are essential in selecting the type of pollinators they need. For example, large petals and flowers attract pollinators at a significant distance or that are large. Collectively the color, scent, and shape of petals all play a role in attracting or repelling specific pollinators and providing suitable conditions for pollinating.

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Some pollinators include birds, bats, insects, and wind. In some petals, you can distinguish between a lower narrowed, stalk-like basal part referred to as the claw and a wider distal portion referred to as the blade. Often, the claw and blade are at an angle from one another.

Flower Petal in Pollination

Wind pollination

Wind-pollinated flowers often have dull and small petals and produce no scent or little scent. Some of these flowers have no petals at all. Flowers that depend on wind pollination will produce large amounts of pollen because most of the pollen scattered by the wind tends not to reach other flowers.

Attracting insects

Flowers have various regulatory mechanisms to attract insects to them. One such helpful mechanism is the use of color guiding marks. Bees or butterflies can see the ultraviolet marks on these flowers, acting as an attractive mechanism that is not visible to the human eye. Several flowers contain a variety of shapes acting to aid with the landing of the visiting insect. They also influence the insect to brush against anthers and stigmas.

One such flower example is the pohutukawa, which regulates color differently. The pohutukawa contains small petals and bright large red clusters of stamens. Another attractive mechanism for flowers is the use of lovely scents for humans. One such example is the rose.

On the other hand, some flowers smell like rotting meat and are attractive to insects such as flies. Darkness is another factor that flowers have adapted to, as nighttime conditions limit vision and color perception. Fragrance can be beneficial for flowers pollinated at night by moths and other flying insects.

Attracting birds

Flowers pollinated by birds must be large and colorful to be visible against natural scenery. In New Zealand, such bird–pollinated native plants include kowhai, flax, and kaka beak. The flowers adapt the mechanism on the flower petal to change color, acting as a communicative mechanism for the bird to visit. An example is the tree fuchsia (Fuchsia excorticata) – is green when they need to be pollinated. But it turns red for the birds – when they want the birds to stop coming to them for pollinating the flower.

Bat-pollinated flowers

Short-tailed bats can pollinate flowers. An example of this is the dactylanthus. This plant has its home under the ground acting the role of a parasite on the roots of forest trees. It has only its flowers pointing to the surface, and the flowers lack color but have the advantage of containing much nectar and a strong scent. These act as a helpful mechanism in attracting the bat.

Final Thought

The evolution of flowers and the role of petals have been studied from the 18th century to the present day. Flower petal play a significant role in pollination of plants.

Read related articles like reproduction in plants, plant seeds, heat stress, heat wave, weed management, and more.

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