Angiosperm - A complete plant having unique phenomenon double fertilization

Angiosperm - A General view

• Angiosperms or flowering plants are higher plants that occupy top positions in the plant kingdom.

• An angiosperm is a complete  plant bearing fruit , seed flowers etc. 

• Angiosperms belong to one of the most diverse and largest extant groups of plants found in the universe.

• There are about more than  250,000 living species of flowering plants on the earth and they have great diversity. 

• These plants are  well developed and have an elaborate process of sexual reproduction   in which an egg is fertilized and developed into a seed in an enclosed hollow ovary.

• The seed in Angiosperms are found in the flower unlike the gymnosperm. 

• In gymnosperms, the seeds are developed in female strobili or female  cones. Male and female reproductive organs are easily distinguished inside the flowers of angiosperms.

Read more about the Gymnosperm

• The ranges of size in angiosperms  varies from Angiosperms from tiny herbs to  giant  trees.

• They can acquire size from millimeters  to large trees that are over 100 meters tall. 

👌👌Remember - The most diverse family of angiosperms are Orchidaceae  belonging  to the orchid family.

Root systems in flowering plant 

• The part of the plant that is suspended inside the soil is called the root system.

• The system includes roots and root hair  and their associated structure.

• The roots provide  anchorage to  the plant, and absorb water and minerals from the soil with their root hairs.  

• In flowering plants, Root systems are classified into  primary root systems and tertiary root systems. 

• The primary root systems consist of a taproot which grows vertically downward. Tap root produces various smaller lateral roots  that may grow horizontally or diagonally. These are termed as  secondary roots.

• The main difference between the primary and tertiary root systems is that the primary root remains present in the plant for a very   short time and it is replaced by secondary than tertiary root as per the requirement.

Shoot systems in flowering plant 

• The Aerial  part of the plant that bears the leaves and flowers is called the stem.

• The stems maintain the supply of  water and minerals  and transport  them directly to the leaves, flowers, and plants.

• The stem of the plant is connected to the root systems for the continuous flow of nutrients through the hypocotyl.

• The leaves are attached to the stems at the nodes and internodes are the regions that lie in between  the two successive nodes.

• Axillary and dichotomous are the two forms of branching system present in angiosperms.

Leaves in flowering plant 

• The Leaves are  also the aerial part of the flowering plant.

• The process of photosynthesis take place  on the surface of the leaves and thus it appears green in most of the plants

• The leaf base, stipules, petiole, and lamina are the parts of the leaf. The  stipules are present at each turn of  leaf base while the blade and the leaf base are connected with the help of petiole.

• In  Some angiosperms, leaves lack petioles whereas in some leaves, stipules are absent. 

Flowers and reproduction in Flowering Plant 

• Flowers are beautiful and attractive creatures in flowering plants.

• Male,and female reproductive structures are found inside the flower. 

• Stamen is male reproductive structure and is made up of two  parts Anther and filament. Anthers produce microspores of pollen grains inside  the microsporangia.

Read more about the Pollen grains

• Pistil or carpel is female reproductive structure and comprises three parts- Stigma, style and ovary. Inside the ovary 

• Ovule is present. Ovule encloses the embryo sac. Embryo sac has antipodal cells, synergids, egg and polar nuclei.

• Pollen grains are transferred from anther to stigma by the pollination . Pollen grains are germinated in the form of a pollen tube and render two male gametes into mature embryo sacs.

• At embryo sac first male gamete fuse with egg through syngamy and form diploid zygote.

• Second male gametes fuse with polar nuclei and form triploid primary endosperm nuclei  by the triple fusion. This is known as double Fertilization. It is the characteristic feature of flowering plants.

Read more about the Double Fertilization

• After fertilization, zygote is changed into an embryo, and the primary endosperm nucleus is developed into endosperm. In addition to this, ovule and ovary are changed into seed and fruit respectively.