Types of reproduction in plants, Typical flower, Structure & sex of flower
Living organisms perform seven vital processes which are: Nutrition, Respiration, Growth, Excretion, Sensation, Reproduction & Motion. All these vital processes aim to continuity the life of the living organism except the “Reproduction process” which aims to continuity its species and protects it from extinction and the life of the individual doesn’t depend on it.
It is a vital process that aims to secure the existence and continuity of living organisms species by producing new individuals of the same species to prevent them from extinction.
Types of reproduction in plants
There are two kinds of reproduction in plants:
- Sexual reproduction through male and female reproductive organs in flowers.
- Asexual reproduction through the various vegetative parts of the plant except flowers.
Sexual reproduction in Plants
Origin of the flower
It arises from a floral bud that emerges from the axle of a leaf called a bract. Bract is the green leaf, where the floral bud emerges from its axle and developed into a flower. The axle may carry a number of flowers which are known as inflorescence. An inflorescence is a group of flowers carried on the same axle.
Structure of the flower
If you examine a flower, you will notice that the flower has a thin neck (pedicle) ends in a swollen part (receptacle) which carries the floral leaves in four different floral whorls:
It is the swollen part upon the flower pedicle, on which the floral leaves exist.
Four different floral whorls
The calyx is the first (outermost), whorl of the floral leaves, It consists of a group of green leaves, each leaf is called a “sepal”, Its function: It protects the inner parts of the flower specially before blooming.
It is the second whorl (following the calyx) of the floral leaves. It consists of a group of bright coloured scented leaves, each leaf is called a “petal”. Its function: It protects the reproductive organs. It attracts insects to the flower, which helps in the reproduction process.
It is the third whorl (following the corolla) of the floral leaves, It is the male reproductive organ of the flower, Its leaves are known as “stamens”. Each stamen consists of a fine filament ends in a sac known as the anther, which is divided into two parts, each part has two chambers containing pollen grains. Its function: It produces pollen grains (inside the pollen chamber).
It is the fourth (innermost) whorl of the floral leaves, It is the female reproductive organ of the flower, Its leaves are known as “carpels” which resemble the flask in shape. Each carpel consists of a swollen part called the ovary, which is connected with a tube called the style, which ends in an opening called the stigma, It produces ovules (inside the ovary).
The flower is considered as a typical flower if it contains four different floral whorls. The typical flower is a flower that contains four floral whorls. Flowers are different from each other in the separation or fusion of the sepals and petals, like in the flowers of wallflowers (Manthoor) and Petunia.
The petals of corolla are colourful and scented to attract insects to the flower which helps in the sexual reproduction process. The androecium is the male reproductive organ of the flower because it produces pollen grains. The gynoecium is the female reproductive organ of the flower because it produces ovules.
The sepals of calyx and petals of corolla might be of the same shape and colour as in onion flower. that’s why we call the two whorls together the perianth. Hay-fever is a disease infecting people who have an allergy to pollen grains, the symptoms of this disease are: inflammation of the mucus membrane of the nose, running nose, continuous sneezing, and tear flow.
Sex of flowers
Flowers are classified according to sex into two types which are Bisexual flower and Unisexual flower:
- Bisexual flower (hermaphrodite): Flower that carries both male and female reproductive organs. Examples: Flowers of most plants such as Flax, Tulip, Petunia, and Wallflower.
- Unisexual flower: Flower that carries either male or female reproductive organ only. Examples: Flowers of some plants such as Palms, Maize, and Pumpkins.
The flower of the tulip plant is a bisexual flower because it contains both stamens and carpels together. The flowers of palms are unisexual flowers because some of them contain only male reproductive organs (stamens) and the others contain only female reproductive organs (carpels). The flower of the bean plant is a typical bisexual flower because its flower contains four whorls.
Pick up a bunch of flowers and remove the lowermost leaves from the flower pedicle, and organize them in groups to be tied to the pedicle. Hang them in an upside-down position in a dark, well-ventilated room for one week.