Parts of a Plant (Third Grade Life Science continued)
Leaves come in many shapes and forms. Some leaves are flat, some are small, others are round, while others are spiky or curly. The two main types of leaves are simple and compound. Simple leaves can easily be seen. This is one leaf per petiole. Compound leaves can have a long petiole with several leaves attached to it. Often the petiole of these plants are mistaken for stems, but you can tell if it's a stem or a petiole by seeing how the leaf is attached to the plant.
It was previously mentioned that stems support the plant's leaves and flowers. Flowers, the fourth plant part are responsible for a plant's reproduction. Flowers can produce seeds (from the ovule) or fruits that protect seeds (from the ovary.) It is within flowers that plant eggs (called ovules) are fertilized by pollen and the fruit or seeds begin their lives.
In order to properly understand plant reproduction, you have to understand the parts of a flower. Flower buds are protected by green leaf like structures called sepals. After the flower blooms, you will often find the sepals at the bottom of the flower base, outside of the petals. The petals of the flower are the colored leaf like structures that surround the inside of the flower. Petals come in many colors in order to attract pollinators (we will see why this is important later.)
Within the flower's petals are several structures. The first one, the pistil if often found at the center of the flower. At the bottom of the pistil is the flower's ovary where the ovules or eggs can be found. On top of the pistil is the stigma, which is sticky and often roundish. Connecting the ovary and the stigma is the style, a stem like structure. The pistils of most flowers are surrounded by several stamens. These are thin structures held up by a filament. At the end of the filaments are the anthers which contain the pollen needed for reproduction.
When pollen from the anther becomes transferred onto the stigma, it travels down the style and onto the ovary. The ovules are fertilized and seeds and fruit begin to form. This process of pollination can happen several ways. Either the wind moves pollen towards the stigma or pollinators (bees, butterflies, insects, and birds) who are attracted to the flower's petals land on the flower and in the process move the pollen from the anther to the stigma. The reason why flower petals need to be attractive is so that birds and bees take interest in them and aid the plant's reproduction.
The next parts of the plant (though no longer in the main parts) are the seeds and fruits. If you have a plant that produces fruit, the ovary of the plant turns into the fruit and within this fruit, the seeds are found. Plants that don't produce fruit simply produce seeds or seed pods.
Seeds are little plant embryos which contain everything the plant species needs to start again or to grow into new plants. Some fruit have just one seed at its center (like a mango) while other fruit have multiple seeds (like watermelons.) When you plant a seed, the plant will begin growing, forming roots, stems, leaves and flowers.
Next Article: How Plants Grow
