June 7, 2025
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Life Cycle of Plants | How They Grow and Reproduce

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life-cycle-of-a-plantThe lifecycle of plants describes how a plant begins its life, grows to maturity, reproduces, and restarts the cycle. Every plant, similar to other living things, follows a specific series of stages in its lifecycle that ensures the survival of its species.

What is the Plant Life Cycle?

Plants are dynamic living organisms that grow and reproduce in a repeating cycle. Their lifecycle begins with a seed and goes through various stages until reproduction, at which point new seeds are produced and the lifecycle restarts. The lifecycle of plants is crucial for the survival of plants and the maintenance of ecosystems.

Stages of Plant’s Life Cycle

Plants begin their life journey as seeds. Once these seeds are buried in the soil, they germinate. Following germination, they grow first leaves and Roots. From there, plants keep growing until they reach maturity. At this stage, plants undergo reproduction by pollination and produce new seeds, restarting the cycle.

In short, here are the most important stages that plants undergo:

  • Seed
  • Germination
  • Seedling
  • Growing to Maturity
  • Reproductive Stage
  • Seed Dispersion

Seed – 1st Stage

sunflower-seedsunflower-seed
sunflower-seed

Seeds are the embryos of plants, packed with essential nutrients for early growth. These are encased in a tough outer coating and remain protected until environmental conditions become right for germination.

These seeds are dispersed naturally across the land through flowing water, wind, animals, and even human activity. Once a seed reaches a suitable environment with sufficient moisture and appropriate Temperature, it germinates and starts its lifecycle.

Germination – 2nd Stage

Plants are the living things that grow from tiny seeds or spores to mighty trees. They start their life as a weak creature that thrives on ground and water to grow. The starting point of their life is due to a process called germination. Germination allows the seeds – and also spores – to sprout and become a seedling (very young plant). Parts of a Seed Before discussing the process of germination, it is important to know about the parts of seeds. There are 3 main parts of the seed, which are: 1. Seed Coat – The first things you can see on a seed is its coat – also called seed coat. It is usually a hard outer layer that protects the seed from damage. Also, many kinds of seeds have a soft seed coat that can easily be damaged by pressing them with hands. 2. Embryo – The embryo is the actual part of a seed that grows from the cells that it contains to become a plant. It has 4 main parts, which are epicotyl, hypocotyl, radicle, and cotyledons. 3. Endosperm – The endosperm is like a food storage for the seed. It usually surrounds the embryo of the seed, and it provides all the necessary food (starch and protein) until the seed germinates to a seedling. Conditions for Germination Seeds depend on the environmental conditions for germination. Some seeds successfully germinate, while others don’t. Germination needs a right condition to sprout the seeds. The most important environmental conditions that need to be at the right level are water, temperature, oxygen, and light or darkness. Let’s discuss each of these environmental conditions. • Water – The germination process highly depends on the amount of water present in the soil. Because seed coat is usually dry, it needs to be moistened by water to break its coating. Furthermore, when the water is absorbed in the seed, it activates the certain enzymes. These enzymes break down the stored food and convert it into useful chemicals that supply energy to the embryo. • Temperature – Each kind of seed needs a different range of temperatures to germinate. Some seeds germinate in cold temperatures, while others require hot temperatures for germination. The seeds usually don’t germinate if the temperature is not favorable. • Oxygen – seeds use oxygen during metabolism when germinating. Majority of the seeds are buried in the soil. Seed usually take oxygen from the spaces in the soil until they grow their leaves for photosynthesis. If a seed is buried at a great depth, then it is difficult for the seed to get oxygen. • Light or darkness – It is not an important factor to consider. Because the majority of the seeds have no any effect of light or darkness. But, some seeds have the impact of light. The light or darkness usually trigger the germination process for these seeds. Process of Germination Germination of seed follows four main changes that are occurred in steps. These steps are imbibition, respiration, Mobilization of food reserves, and development of the embryo into a seedling. Let’s discuss each of these steps in detail. 1. Imbibition – This is the first step that starts with the absorption of water – also called imbibition. As the seed absorbs the water through small pores in its seed coat, it rehydrates and swells. The swelling of the seeds forces the seed coat to break, which allows the radicle (first root) to come out and absorb nutrients from the soil. 2. Respiration – When water enters into seed, it starts the metabolic activities in the embryo. The oxygen is absorbed by the seed from the soil for generating energy. Oxygen provides the necessary energy to the seed until it grows leaves and starts photosynthesis. 3. Mobilization of Food Reserves – During germination, metabolism takes place. The seed needs food for digestion. The food of the seed is usually stored in the endosperm. The food is mobilized from the endosperm to the embryo. The outer layer of the endosperm secretes the special enzymes that are used for digestion. 4. Development of Embryo into Seedling – The transportation and digestion of food cause the cells of the embryo to develop and divide. The embryo grows until it forms into a seedling. The seedling has every necessary part to start photosynthesis and further grow into the mature plant. Rate of Germination When the seeds are planted in an agricultural area or garden – not every seed in germinated. To measure how many seeds have been germinated from total seeds, it is called germination rate. Germination rate is usually in percentage, which describes how many seeds have been germinated in a given amount of time. For example, 100 seeds are planted in a garden and 65 seeds have been able to germinate. Then, the rate of germination will be 65%. Facts • The seeds of proteas have the unusual ability. They start to germinate after they are exposed to smoke. This ability is definitely evolved in them for surviving in fire-catching forests. • Coco-de-Mer is a seed that has a weight of around 30 kg. It is considered as largest seed on the earth. • Not every plant grows from the seeds. Many plants grow from the spores of their parent plant. Spores are the remaining of a plant after it dies, or they may be the parts of a plant.Plants are the living things that grow from tiny seeds or spores to mighty trees. They start their life as a weak creature that thrives on ground and water to grow. The starting point of their life is due to a process called germination. Germination allows the seeds – and also spores – to sprout and become a seedling (very young plant). Parts of a Seed Before discussing the process of germination, it is important to know about the parts of seeds. There are 3 main parts of the seed, which are: 1. Seed Coat – The first things you can see on a seed is its coat – also called seed coat. It is usually a hard outer layer that protects the seed from damage. Also, many kinds of seeds have a soft seed coat that can easily be damaged by pressing them with hands. 2. Embryo – The embryo is the actual part of a seed that grows from the cells that it contains to become a plant. It has 4 main parts, which are epicotyl, hypocotyl, radicle, and cotyledons. 3. Endosperm – The endosperm is like a food storage for the seed. It usually surrounds the embryo of the seed, and it provides all the necessary food (starch and protein) until the seed germinates to a seedling. Conditions for Germination Seeds depend on the environmental conditions for germination. Some seeds successfully germinate, while others don’t. Germination needs a right condition to sprout the seeds. The most important environmental conditions that need to be at the right level are water, temperature, oxygen, and light or darkness. Let’s discuss each of these environmental conditions. • Water – The germination process highly depends on the amount of water present in the soil. Because seed coat is usually dry, it needs to be moistened by water to break its coating. Furthermore, when the water is absorbed in the seed, it activates the certain enzymes. These enzymes break down the stored food and convert it into useful chemicals that supply energy to the embryo. • Temperature – Each kind of seed needs a different range of temperatures to germinate. Some seeds germinate in cold temperatures, while others require hot temperatures for germination. The seeds usually don’t germinate if the temperature is not favorable. • Oxygen – seeds use oxygen during metabolism when germinating. Majority of the seeds are buried in the soil. Seed usually take oxygen from the spaces in the soil until they grow their leaves for photosynthesis. If a seed is buried at a great depth, then it is difficult for the seed to get oxygen. • Light or darkness – It is not an important factor to consider. Because the majority of the seeds have no any effect of light or darkness. But, some seeds have the impact of light. The light or darkness usually trigger the germination process for these seeds. Process of Germination Germination of seed follows four main changes that are occurred in steps. These steps are imbibition, respiration, Mobilization of food reserves, and development of the embryo into a seedling. Let’s discuss each of these steps in detail. 1. Imbibition – This is the first step that starts with the absorption of water – also called imbibition. As the seed absorbs the water through small pores in its seed coat, it rehydrates and swells. The swelling of the seeds forces the seed coat to break, which allows the radicle (first root) to come out and absorb nutrients from the soil. 2. Respiration – When water enters into seed, it starts the metabolic activities in the embryo. The oxygen is absorbed by the seed from the soil for generating energy. Oxygen provides the necessary energy to the seed until it grows leaves and starts photosynthesis. 3. Mobilization of Food Reserves – During germination, metabolism takes place. The seed needs food for digestion. The food of the seed is usually stored in the endosperm. The food is mobilized from the endosperm to the embryo. The outer layer of the endosperm secretes the special enzymes that are used for digestion. 4. Development of Embryo into Seedling – The transportation and digestion of food cause the cells of the embryo to develop and divide. The embryo grows until it forms into a seedling. The seedling has every necessary part to start photosynthesis and further grow into the mature plant. Rate of Germination When the seeds are planted in an agricultural area or garden – not every seed in germinated. To measure how many seeds have been germinated from total seeds, it is called germination rate. Germination rate is usually in percentage, which describes how many seeds have been germinated in a given amount of time. For example, 100 seeds are planted in a garden and 65 seeds have been able to germinate. Then, the rate of germination will be 65%. Facts • The seeds of proteas have the unusual ability. They start to germinate after they are exposed to smoke. This ability is definitely evolved in them for surviving in fire-catching forests. • Coco-de-Mer is a seed that has a weight of around 30 kg. It is considered as largest seed on the earth. • Not every plant grows from the seeds. Many plants grow from the spores of their parent plant. Spores are the remaining of a plant after it dies, or they may be the parts of a plant.When a seed germinates, it awakens from its dormancy and begins to grow. The germination is triggered by moisture, which softens the outer coating and activates the internal Enzymes. The seed absorbs water and becomes swollen, which breaks the outer coating. The activated enzymes convert the stored nutrients into energy that the embryo can use for growth.

Check out https://science4fun.info/seed-germination/

Seedling – 3rd Stage

sunflower-seedlingsunflower-seedling
Sunflower seedling

Once germination is complete, the young plant emerges from the Soil and is called a seedling. At this stage, the seed has been broken and the first roots and leaves of the young plant are developed.

The first leaves, known as cotyledons, prepare food for the plant by Photosynthesis. The newly developed roots anchor the plant and absorb necessary nutrients and water from the soil.

As the seedling develops further, it grows a plumule. The plumule is the early stem from which new leaves will develop. At this stage, plants rely less on the stored food and get energy from sunlight and soil resources.

Growing to Maturity – 4th Stage

mature-sunflower-plantsmature-sunflower-plants
Mature sunflower plants

After the seedling stage, the plant’s growth and development continue until it reaches full maturity.

During this stage:

  • The plant grows rapidly and develops many new structures.
  • Its root system deepens and widens for better support and nutrient absorption. The stem becomes thicker and elongated to support its structures.
  • The branches and leaves multiply, which increases the plant’s ability to capture sunlight for photosynthesis.

The plant needs many necessary things for healthy growth, such as water, nutrient-rich soil, air, sunlight, the right temperature, and adequate spacing from other plants. (For details, check How Plants Grow?).

Once the plant reaches maturity, it moves to the next critical stage – reproduction.

Reproductive Stage – 5th Stage

parts-of-flowerparts-of-flowerIn this stage, the plant develops flowers for the production of seeds. It produces flowers from specialized structures known as determinate Apical Meristem. These are the modified shoot tips that are adapted for reproduction.

A typical flower is composed of both male and female reproductive parts:

  • Stamen (Male Part): It produces the pollen (a powdery substance), which contains male reproductive cells necessary for fertilization.
  • Pistil (Female Part): The pistil is located at the center of the flower and contains the ovary, which houses the ovules (eggs). When the pollen reaches the pistil, fertilization happens, and new seeds are produced.

The pollen from male parts reaches to female parts through wind, insects, and other pollination methods.

Seed Dispersion – 6th Stage

seed-dispersionseed-dispersionOnce seeds are produced, they need to reach new favorable locations where they can germinate and start a new life cycle. This process is known as seed dispersal, and it is essential for reducing competition among plants of the same species. Seed dispersal also helps plants grow in new and far-separated areas.

Methods for seed dispersion:

  • Wind: Strong blows of winds pick the seeds from the plants and carry them away. Moreover, light seeds with wings or fluffy hairs (e.g., dandelions) glide in the air and reach far places.
  • Water: When seeds of plants fall into the river and streams, they are carried away to distant places.
  • Animals: Fruits of plants are eaten by animals that contain seeds. Later on, animals excrete the seeds at different locations. Also, some seeds are sticky and get hooked to animal fur and feathers. They are carried away by animals and fall off later.

Pollination Methods

cross-pollinationcross-pollination
cross-pollination

Pollination is the vital process by which pollen reaches the pistil (female part) from the stamen (male part) happens through several methods:

  • Insect Pollination: Insects, such as butterflies, bees, and beetles, are attracted to flowers for their bright colors and sweet nectar. These insects move from one flower to another and unintentionally carry pollen on their bodies. This way, the pollen is transferred within the same flower and to other flowers.
  • Wind Pollination: Many plants, such as trees and grasses, depend on wind to carry their lightweight pollen. It is because these plants don’t produce an attractive scent or sweet nectar. These plants produce pollen in large amounts to increase their chances of successful pollination during strong winds.
  • Animal Pollination: Animals, including birds and land animals, also play a role in pollination, similar to insects. They visit the plants for food and carry the pollen that sticks to their bodies. They transfer pollen from the stamens to the pistils while moving between plants and their flower.

What about Seedless Plants?

spores-of-fernspores-of-fern
Spores of fern on its leaves

Many plants don’t produce flowers or seeds for their reproduction. Instead, they grow from the spores of their parent plants. Spores are dust-like, tiny reproductive units that are formed by the parent plant. The new plants grow from these spores when the environment is moist and the temperature is favorable.

See Non-Flowering plants for further information.

FAQs

What is Self-Pollination and Cross-Pollination?

In self-pollination, the pollen from the anther reaches the stigma in the same flower, or a different flower in the same plant. However, cross-pollination is a bit different. It happens when the pollen from the anther of one plant reaches the stigma of another plant’s flower having the same species. Both of these processes can happen naturally as well as artificially.

What is the Asexual Reproduction of Plants?

The plants that grow without fertilization are called asexually reproduced plants. Asexual reproduction can occur through fragmentation, spores, budding, and vegetative propagation. Potatoes are a famous example of the asexual reproduction of plants.

What is the Alternation of Generations?

The life cycle of plants is divided into two main phases: the haploid and the diploid. These two phases of the plant lifecycle can also alternate, and this process is called the alternation of generations.

The alternation of generations is the primary type of lifecycle in plants. In this lifecycle, the haploid sexual phase (gametophytes), which consists of only a single set of chromosomes, turns into a diploid asexual phase (sporophytes), which contains two sets of chromosomes. Both haploid and diploid are multicellular, and their cells split by meiosis and mitosis processes of cell division, respectively. This alternation of generation is not only common in plants but also found in algae and Fungi.

Interesting Facts

  • The Great Basin bristlecone pine is the longest-living plant found in the world. Its age is measured to be around 5,056 years.
  • Coco de Mer is the seed of a palm tree, it can weigh about 18 Kg (40 pounds) and reach a height of 12 feet.
  • Rose, Jasmine, and Lily are the strongest-smelling flowers.
  • When a seed is not germinating, it is in a dormant state. In this stage, it is no more than dead stuff.

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