Specialized Plant Structures for Plant Reproduction

Probability of Plant Reproduction – Specialized plant structures

Introduction:

Plants have different parts, like roots, stems, leaves, flowers, and fruit. These parts act like different components of a system that help the plant to perform various functions required for its growth, reproduction, behavior, and survival.

Plants require roots and stem for the transportation of water and nutrients. They help provide anchor and support to the plant. Leaves perform the process of photosynthesis and transpiration which is essential for survival.

Explanation:

Some plants may also have specialized structures that help them in various ways. These specialized structures are modifications of the main parts of the plant and may include tendrils, thorns, bulbs, flowers, fruits, etc. They help the plant adapt to its environmental condition and increase its chances of survival.

Flowers and fruits are also specialized structures in plants. These structures increase the chances of reproduction in plants. In this session, we will learn how these structures increase the probability of plant reproduction.

How do Plants Reproduce?

Reproduction is a biological process that enables the continuity of the species, one generation after another.  Plants carry out asexual reproduction by means of budding, vegetative propagation, and fragmentation. Whereas sexual reproduction requires the fusion of male and female gametes derived from either one or two parents. In most plants flower is the reproductive organ.

Structure of a Flower:

A flower is the colorful part of the plant that carries out reproduction. Flowers have four main parts which are sepals, petals, stamen and pistil.

Sepals are the outermost part of a flower that protects the interior part. Sepals are typically green and leaf-like. Petals are the large and colorful part of the flower. They are the most prominent structures in a flower and come in different colors, shapes, and sizes.

Stamen is present on the inner side of the petals. It is the male reproductive organ of a flower and contains two main parts, i.e., the anther and filament. The filament is the long cylindrical stalk of the stamen that simply holds up the anther, whereas the anther is a sac-like structure that sits at the top of the filament and is responsible for producing and storing pollen.

Pistil is the innermost part of the flower that contains small bead-like structures called ovules. The pistil is divided into three parts as follows:

• Stigma: The topmost sticky receptive tip of the pistil that receives pollen.
• Style: The stalk that connects the stigma with ovary.
• Ovary: The swollen structure of the pistil that produces ovules.

Pollination:

Pollination is the transfer of pollen grains from the anther to the stigma, and this transfer can be in the same or a different flower.

Self-pollination occurs when pollens are transferred from the anther to the stigma of the same flower. In contrast, cross-pollination occurs when pollens are transferred from the anther of one flower to the stigma of another flower.

Pollination increases the probability of sexual reproduction in plants and can be carried out by the help of multiple factors. Pollen grains are light and can be dispersed by wind or with the help of pollinators.

Pollinators are animals that help in the dispersal of pollen grains from one flower to another. Pollinators include insects, birds, small mammals, bats, etc.

When pollinators like bees sit on a flower to suck and collect nectar, the pollen on the flower sticks to the body of the bee. Now, when this bee sits on a different flower, the pollen gets dispersed on the stigma of that flower, and pollination takes place.

Plant Strategies to Increase Reproduction:

In order to increase the probability of reproduction, a plant uses various strategies to attract pollinators.

Most flowers are brightly colored and help attract butterflies which then increase pollination. Bees are drawn to yellow, blue, and purple and see in a spectrum of ultraviolet light that’s invisible to humans. Many flowers have ultraviolet markings on them called “nectar guides” which draw bees directly to the pollen and nectar of a flower.

Flowers are also shaped in a certain way that attracts pollinators. For example, butterflies favor flat-topped and cluster-type flowers in red, orange, yellow, pink, and blue. Flowers tend to have exposed or long stamen which makes pollen easily accessible to pollinators and increases the chances of pollination.

Flowers tend to produce an aroma after the pollen is produced which attracts insects. Some herbs like sage, oregano, basil, and lavender contain distinct fragrant oils which are particularly delightful to pollinators.

Flowers also produce nectar which is often found at the bottom of a tube of petals. While reaching for the sugary reward, birds need to brush against anthers and stigmas with their long beaks.

Along with pollination, seed dispersal also plays an important role in plant reproduction. Plants use different strategies to enhance seed dispersal and increase the probability of successful reproduction.

Some seeds have hooks or barbs that attach to the fur of passing animals. Later when the animals scratch off the itchy burr the seed gets dispersed.

Some plants produce a fleshy-covering called a fruit that contains seeds inside them. Fruits like apples, blueberries, etc., attract animals and birds to eat them. The animal ingests the fruit and seeds are either spit out or passed through the animal’s digestive tract and excreted in a different place.

This enhances seed dispersal in plants.

Some seeds like nuts have hard shells and these are collected by animals like squirrels or chipmunks to eat. These animals bury the seed in order to store it for further use. This behavior not only helps in seed dispersal but also helps them plant in the ground.