Introduction
We all love flowers for their fragrance and beauty, don’t we? But there is more to it than meets the eye, as flowers carry out many important functions. Flowers contain many structures, which help a plant reproduce, grow and survive.
In this article, you will learn about the anatomy and functions of different parts of flowering plants like the root, stem, leaf inflorescence, flower, fruit and seed.
Anatomy and Functions of the Stem
A part of the plant which lies above the ground, the stem is one of the two structural axes of a vascular plant. Its functions are as follows:
- It holds and supports the fruits, flowers and leaves
- Leaves are arranged on it in a manner that all get enough sunlight to perform photosynthesis
- Water and minerals travel through the plant through the xylem and phloem present in the vascular bundles
- Few stems containing chloroplasts are also able to carry out photosynthesis
- The processes of fertilisation, pollination, and dispersal of seeds are also facilitated by the stem
Growth in the Stem
It occurs in two ways:
- Primary growth occurs at the apical tips of the stem by dividing the meristematic tissue rapidly
- Secondary growth increases the thickness of the stem by lateral meristems
Anatomy of the Root
The root of a plant is present under the ground and is responsible for the absorption of water.
Characteristics of the Root
- The root is the descending portion of the plant axis
- Roots are crucial to maintain the water transportation system in plants
- Roots are positively geotropic
Parts of the Root
- Root cap: Covering the tip of the root, it is a thimble-like structure. It protects the tender root apex
- Region of maturation: It is a part of the root epidermis
- Region of elongation: This is responsible for the meristematic activity of the plant. The cells in this area are very small and have a dense protoplasm
Anatomy of Leaf Inflorescence
A flower is the reproductive part of the plant. Bright and colourful, flowers attract pollinators. Flowers can be solitary or be present in bunches or clusters. Clustered flowers are found on branches different from the other branches of the plant. Such clusters of flowers are known as inflorescence.
Classification of Inflorescence
It is broadly classified into three types based on:
- The position and number of flowers
- The nature of building of the inflorescence
- The sequence of flower development
Commonly, inflorescence is classified into two categories:
- Racemose Inflorescence: Under this type of leaf inflorescence, the axis has unlimited growth. The older flowers are at the bottom and new flowers are at the top. The different types of racemose are as follows:
- Spike: These are flowers without pedicels and arranged in an acropetal manner. For example, barley
- Raceme: These are flowers with pedicels arranged in an acropetal manner
- Corymb: These have an umbrella-like appearance when seen from the top. They consist of pedilicate flowers where the length of the lower-placed flowers is more than that of the upper ones in a manner that they all come at the same level
- Spadix: Spathe, a sheath-like covering that covers the spike, is known as a spadix. The best example of this is the banana
- Umbel: When pedicellate flowers originate from the same place and reach the same level, it is termed as an umbel
- Capitulum: When the flowers are directly placed on the peduncle like a short spike, it is called capitulum. A small capitulum is termed a head
- Cymose Inflorescence: In this, the axis has limited growth. The older flowers are found at the top, whereas the young ones are at the bottom, towards the base of the axis. The different types of cymose inflorescence are as follows:
- Monochasial: There is a lateral branch and the main axis ends in a flower. For example, drosera
- Biparous/dichasial: Under this, the main axis produces two branches at the lower level. Both of them end in flowers at the tip. The pattern is further replicated. Dianthus is one such example
- Cymose capitulum: Here, the peduncle is diminished to form a disc-like shape. This disc carries sessile flowers, with the younger ones toward the edge and the older ones towards the centre
- Polychasial/multiparous: In this case, the main axis produces a flower. It also produces a number of flowers sideways. An example of this is calotropis
Anatomy of a Flower
Let us now look at the anatomy of flowers.
Parts of Flowers
The majority of flowers have the following four parts:
- Petals
- Sepals
- Stamen
- Carpel
Carpel is the female part, while stamen is the male part of a flower. Most flowers are hermaphrodites and have both male and female parts. Some contain any one of the parts and may be male or female.
The stamen is structurally divided into two parts:
- Filament
- Anthers
The carpel has four parts:
- Style
- Stigma
- Ovule
- Ovary
Anatomy of The Fruit
Once fertilisation is done, the ovary becomes the fruit and ovules become the seeds. The main purpose of the fruit is to protect the seed during its development.
Structure of the Fruit
It consists of two parts: the seed and pericarp
Anatomy and Functions of Seed
It is a part of the plant which develops as a result of sexual reproduction. It contains the young embryo, which can form a new plant.
Functions of The Seed
The basic anatomy of every seed remains the same. It performs the following functions:
- Helps the plant in germination
- Protects the embryo through the seed coat
- Contains food reservoirs in the form of endosperms
Conclusion
The study of the anatomy of different parts of flowering plants like the root, flower, stem, seed, leaf inflorescence is crucial to understanding the functioning of a plant.