What is a life cycle? Well, some say it is the genesis of life to its eventual death. So, a plants life cycle starts when the seed is first put into the soil and breaths some oxygen and then watered all the way to withering. The essentials of starting a life of a plant include warmth, oxygen and water.
As the plants germinates, it will start requiring other essentials such as fertile soils, sunlight for photosynthesis and of course water.
The moment a seed falls on the ground, life starts. In nature, there are many types of plant life. However, the most advanced of the plant life is seen in the angiosperms (flowering plants). They have alluring flowers that help them attract pollinators and thus spread their seeds. The major stages of a plant life cycle include;
- Seed Dispersal
All plant lifecycles start off with a seed. Note that all seeds have small plants inside their embryo. There are two major categories of seeds. These are the dicots and the monocots. Dicots, in addition to having an embryo, have two cotyledons. A good example of a dicot is a bean seed. Note that the cotyledons is where the seed stores its food. The cotyledons also happen to be the first leaves of the plant as it emerges from the ground during germination. Contrastingly, monocots have only one cotyledon. A great example is he corn seed.
Both types of seeds have a miniature root system. They also feature a hard coat on the outside to protect the embryo. Some seeds can keep their germination properties for a long time as long as they are kept in a dry and cool place.
For a seed to start to germinate, it will need warmth, water and oxygen. Some seeds need light. Note that the dicots need the moisture more because they have a very strong outer membrane that needs some softening to develop their root system.
After a seed is dropped into the ground, its outer membrane soaks in water until the seed splits. Monocots (such as the corn seed) do not split however. They just open on one end.
The process of germination will then commence when the stem (hypocotyl) pushes through the soil with the seed leaves. The process is also referred to as sprouting. While the step is pushing upwards, the tiny roots push downwards into the soil looking for water, nutrients and providing support to the growing stem.
For the seed to germinate, it have to be planted at the right place and at the right time. For example, the prairie grass seed has to pass through fire to sprout. Others have to go into an animal stomach to get scraping in order to soften it for germination.
The Growth Process
The growth process is largely dependent on a process known as photosynthesis. It is the process by which plants make their own food in the leaves using chlorophyll, sunlight, water, and carbon dioxide.
The food made by the leaves is stored in form of sugars in the stem and the root system. The root is also important for anchoring the plant as well as absorbing nutrients and water from the soil. The nutrients (starches and sugars) are then converted into energy, thus helping the plant grow at the top of the stem (meristem).
After a period of growth (sometimes months and sometimes years in some plants), a flower bud will develop and this will signify that the plant has reached maturity and is ready for reproduction.
The Reproduction Stage
The bud that later opens into a flower is protected by the sepals. Once the sepals open, they the little flower inside blossoms into a mature flower. The flower has reproductive parts. To aid the process of reproduction, the flower has very attractive petals that are not only brightly colored but also scented to attract the pollinators. This is a very important stage of a plant’s life.
The female reproductive part of a flower is known as the pistil. It is made up of four parts namely the ovules, the ovary, the style and the stigma. Its male counterpart is known as the stamen and has is made up of the anther – where the pollen is made- and the filament, a long string through which the pollen pass through from the anthers.
At the heart of the flower is a long slender tube that is referred to as style. It opens up into a funnel like opening that is known as the stigma. Its role is to collect the pollen grains. The stigma is sticky and hairy to enhance its capability to collect pollen grains.
In order to aid the process of pollination, sometimes the pistil will be surrounded by several stamens. The pollen grains collected on the stamen travel down the style into the ovary where the ovules will be waiting for fertilization. The fertilized egg becomes the seed and the flower withers to give way to the growth of ovary into a fruit.
In some flowers, you will find only male parts while others have the female parts. Sometimes they are located far apart and thus to transport pollen grains to the female parts, a flower will need agents of pollination such as water, wind, birds, animals, insects etc. Without the pollinators, fertilization will not occur.
Sometimes, flowers get fertilized with pollen grains from other flowers in a process called cross-pollination. The process results in stronger plants. It is the bright petals and sweet smell of nectar that attract the pollinators. The flowers are genetically coded to adapt to specific pollinators. A good example is the dead flower that smells like rotting flesh to draw in the flies that get pollen stuck on their legs and wings as they move from flower to flower and thereby aiding cross-pollination as they also get food. Animals and humans also help transport pollens from flower to flower when the grains stick to the animal furs and human clothes.
The final stage of the plant life cycle is the seed dispersal. Some seeds – such as the dandelion seeds – are spread by dispersal agents such as the wind. Others rely on the wind and animal furs to take them to new locations. Water lilies seeds are transported to new locations by water. Most importantly, humans deliberately plant seeds as one of the most important agents of seed dispersal.