Plant Life Cycle: Stages, Parts of a Flower

The life cycle of plants

Lifecycle is an ongoing and repeated process that defines how a living thing commences life, becomes mature, goes through all the steps of life, and passes away. There is a specific life cycle for all living beings on Earth, including the life cycle of a flowering plant which ensures their survival. 

The stages a plant experiences from its birth to its death, when the cycle repeats, are described as the life cycle of plant. The haploid phase, the gametophyte phase, and the diploid phase, commonly referred to as the sporophyte phase, are the three phases that make up the Life of Plant Cycle. These stages alternate, which is referred known as the alternation of generations. 

Generational alternation is exhibited by plants, algae, fungi, bryophytes, and pteridophytes. In the course of Life cycle of plants, mitosis and meiosis divide haploid and diploid cells, producing haploid and diploid plant bodies. 

What is a Plant Life Cycle?

As plants grow and reproduce as any other living being does, they are indeed living things. They commence a new life, grow and develop, and return to the first reproduction stage by following a cyclic process. The life of the plants commences from the seed form, which matures to become grown-up plants. 

Stages of Plant’s Life Cycle

The life cycle of plants starts from the seed form, which is buried in the ground through different methods. It germinates and gives rise to the first leaves known as seedlings. Following this, the growth of the plant continues, and it reaches a mature stage. Then it pollinates, seeds are formed, and that species gets an opportunity to continue survival by commencing the life cycle again. 

There are five main stages to the plant life cycle: 

• Seed
• Germination and Seedling
• Becoming mature
• Growing flowers and seeds and undergoing pollination
• Dispersion of seeds

SEED – 1st Stage

Seeds can be compared to human babies as they contain the plant embryo, which has the much-needed food and an outer protective coat. There are many ways by which seeds are dispersed across the land, including water, moving air, humans, and other animals. When they assimilate the necessary things, like water and the ideal temperature, and fall on the favourable soil, they germinate and commence their life journey.

Germination and Seedling – 2nd Stage

When the soil conditions are ideal, the seed begins to germinate. It first breaks the outer coat and starts growing its first leaves and roots. Once the first life sign from a seed shows up out of the soil, it is referred to as a seedling. When the leaves and roots develop, they start functioning. The roots carry out their role of absorbing water and nutrients, while the leaves carry out photosynthesis to produce food. 

Growing to maturity – 3rd stage

The seedling progresses to full maturity as it continues to grow. Many things are needed during the life cycle of a plant while it’s growing. When the plant matures, it has to develop sturdier roots and also increase its leaves and branches. They can develop flowers and seeds at this stage.

Flowering, Pollinating, and Seeding – 4th stage

Once plants mature, they can develop flowers. A flower of the lifecycle of a flowering plant has the male reproductive parts and the female reproductive parts of the plant. The male sexual part of the plant is referred to as stamen, while the female sexual part is referred to as pistil. The stamen part of the flower produces pollen grains. The seeds of the plant develop in the pistil part of the flower. Typically, the pollen grains go to pistils with the help of insects that visit flowers to suck on their sweet juices. When the pollen grains come in contact with the pistils, fertilisation occurs, and seeds are formed. 

The male and female parts of many plants are separated very far away. In their case, pollination is mainly facilitated by the winds and insects. The winds often carry the pollen grains to the female reproductive parts. Insects also wander from one plant to another to suck their sweet juices. After they enter a flower, pollen grains get attached to the surface of their bodies, so when they visit the female parts of a flower, pollen grains land there. 

The parts of the flower

Did you think that flowers were just a pretty-looking bunch of petals? Well, they are! But they are also much more complex, having different parts, all specialised to carry out specific functions. 

The inside of the flower contains the male reproductive part and the female reproductive part, which help it to reproduce. Let us look at all the parts of the flower closely. 

Petal: It is the colourful part of the flower whose function is to attract insects.

Stamen: It is the male reproductive part of the plant.

Anther: It is that part of the flower that forms pollen grains.

Filament: It is the structure that gives support to the anther.

Pistil: It is the female reproductive portion of the flower. 

Stigma: It is the part of the flower that collects pollen grains.

Style: It lets the pollen grains travel to the ovary.

Ovary: It is the female reproductive part of the flower that gives rise to seeds on the inside of the ‘ovules.’

Sepal: It is the part that appears on the exterior of the petals. Its function is to safeguard the flower when it is unopened.

Receptacle: It is the part of the flower that attaches it to the plant stem.

Pedicel: It is a stalk whose function is to support one flower.

Seed Dispersion – 5th Stage

 

When the seeds are produced, plants look for a way to disperse them to those places where they can undergo germination and commence their plant life cycle. This job is done by nature, that is, water, moving air, and animals, most of the time. Some plants have seeds covered by fibres that help them glide in the air when they fall from the plant. When gliding, they cover long distances and commence their life far from the parent plants.

What about seedless plants like ferns and mosses?

If you think that all plants reproduce from seeds, it is not true! There are lots of plants that do not form flowers and seeds for reproduction. They, instead, arise from their parent plant’s spores. The spores give rise to new plants that continue their growth. 

How are flowers pollinated?

Pollination is the first stage of reproduction in flowering plants. What exactly is pollination? Pollination is the movement of pollen grains formed on a flower’s anther to the flower’s stigma.

Flowers are pollinated by two main methods— through insects and the wind. Different adaptations are followed by the insect-pollinated flowers and the wind-pollinated flowers. Did you know the fact that besides insects, birds and bats also help in pollination?  

Insect-pollinated flowers: Sweet scents and beautifully coloured petals are what these flowers have. These attributes keep insects coming back for a snack of nectar. Pollen grains are quite sticky. This is helpful because when the insects come in contact with those, they adhere to their bodies. Even the stigmas of these flowers are sticky. They are supposed to catch the pollen when an insect comes in contact.

Wind-pollinated flowers: No scent and green or dull colour are what these plants have. This is because they do not need to attract insects. They are not dependent on them for pollination. The anthers of these kinds of flowers are placed outside the flower. They make pollen grains in large amounts so that the wind picks them up and transports them to the stigmas for pollination.

Fertilisation of flowering plants

When the pollen grains come in contact with the stigma of the lifecycle of a plant of the same species, the style of grain gives rise to a pollen tube that goes to the ovary. After that, male reproductive cells called gametes travel from the grain of grain through the ovary tube, where they meet the female gametes in the ‘ovules ‘through a process known as ‘fertilisation’.

When the pollen fertilises an ovule, it changes into a seed that contains an embryo in the form of a root and a shoot. It also has some stored food that the young plant needs to grow at a later point in the life cycle of a plant. Then the ovary wall develops into a pod or a fruit so that it safeguards the seed. 

Frequently Asked Questions

1. What are self-pollination and cross-pollination?

If the pollen grains are transported to the same flower’s stigma or some other flower of the same plant, it is known as ‘self-pollination’. On the other hand, if the pollen grains are transported to the stigma of a flower on another plant, it is called ‘cross-pollination’.

2. What is germination?

Germination is when a seed changes and commences growing to change into a plant. Roots of a plant develop beneath the soil when the stem and the flowers called shoot develop above the soil. 

3. What is asexual reproduction in the life cycle of plants?

Some plants can reproduce in the absence of the process of fertilisation of an egg cell to give a seed. In such plants, asexual reproduction occurs through which it produces an exact copy of itself. There are several ways by which plants can reproduce asexually. For instance, few plants, such as daffodils and snowdrops, have bulbs. Some other plants, like potatoes, have tubers. These lie underground and form new plants when the next year comes.

4. What are the 5 stages of the Life cycle of Plants?

There are five stages in the Life cycle of Plants: the seed, the germination of the seed, the seedling, the adult plant, and pollination and fertilization.

5. What is called the Life cycle of Plants?

The life cycle of a plant describes its several stages, starting with seed, germination, and seedling, and ending with the mature plant.