Answer
Verified
432.3k+ views
Hint: In angiosperms, functional megaspore develops into a female gametophyte which is located in the nucellus. In plants, fertilization occurs in this location and forms the egg cell or nucleus developing into an embryo after fertilization.
Complete Step by Step Answer: The functional megaspore grows into an Embryo sac in angiosperms. An Embryo sac is a female gametophyte located in the nucleus and is formed from functional megaspore.
The nucleus of chalazal functional megaspore (fourth from micropyle) divides mitotically to form two nuclei which move to opposite poles, forming the 2 nucleate embryo sac. Two sequential mitotic nuclear divisions results in the formation of 4-nucleates and later the 8-nucleate stages of the embryo sac. One nucleus from each pole moves to the middle to form polar nuclei.
At this stage, the following changes occur - Three of the nuclei (n) get organized as the cells of the micropylar end forming egg apparatus. One is the egg cell (n) and two are the synergids (n). - three nuclei get organized as the antipodal cell (n) at the chalazal end. - Two nuclei in the center are called the polar nuclei (n). - This constitutes a 7-celled and 8-nucleated embryo sac.
So, the answer is “Embryo sac”.
Additional Information: The process of formation of megaspores from the megaspore mother cell (MMC) is called megasporogenesis. Ovules typically discern a single mother cell of the megaspore in the nucellus micropylar area.
The MMC undergoes meiosis and forms a four haploid megaspore linear tetrad. From which three degenerates (micropylar end) and three functional (chalazal end) remain.
Note: - MMC is a large cell containing dense cytoplasm and a prominent nucleus. - To ensure the formation of haploid female gametophyte before fertilization MMC undergoes meiosis. - These mitotic divisions are strictly free nuclear i.e.; nuclear divisions are not followed immediately by cell wall formation. - In the majority of angiosperms, one of the megaspores is functional while the three degenerates. Only the functional megaspore (n) develops into the female gametophyte. This process of embryo sac formation from a single megaspore is termed as Monosporic development. - Polygonum type of embryo sac is found in 80% of flowering plants. This development has been studied in Polygonum by Strasburger.
Complete Step by Step Answer: The functional megaspore grows into an Embryo sac in angiosperms. An Embryo sac is a female gametophyte located in the nucleus and is formed from functional megaspore.
At this stage, the following changes occur - Three of the nuclei (n) get organized as the cells of the micropylar end forming egg apparatus. One is the egg cell (n) and two are the synergids (n). - three nuclei get organized as the antipodal cell (n) at the chalazal end. - Two nuclei in the center are called the polar nuclei (n). - This constitutes a 7-celled and 8-nucleated embryo sac.
So, the answer is “Embryo sac”.
Additional Information: The process of formation of megaspores from the megaspore mother cell (MMC) is called megasporogenesis. Ovules typically discern a single mother cell of the megaspore in the nucellus micropylar area.
The MMC undergoes meiosis and forms a four haploid megaspore linear tetrad. From which three degenerates (micropylar end) and three functional (chalazal end) remain.
Note: - MMC is a large cell containing dense cytoplasm and a prominent nucleus. - To ensure the formation of haploid female gametophyte before fertilization MMC undergoes meiosis. - These mitotic divisions are strictly free nuclear i.e.; nuclear divisions are not followed immediately by cell wall formation. - In the majority of angiosperms, one of the megaspores is functional while the three degenerates. Only the functional megaspore (n) develops into the female gametophyte. This process of embryo sac formation from a single megaspore is termed as Monosporic development. - Polygonum type of embryo sac is found in 80% of flowering plants. This development has been studied in Polygonum by Strasburger.
Recently Updated Pages
How many sigma and pi bonds are present in HCequiv class 11 chemistry CBSE
Mark and label the given geoinformation on the outline class 11 social science CBSE
When people say No pun intended what does that mea class 8 english CBSE
Name the states which share their boundary with Indias class 9 social science CBSE
Give an account of the Northern Plains of India class 9 social science CBSE
Change the following sentences into negative and interrogative class 10 english CBSE
Trending doubts
Fill the blanks with the suitable prepositions 1 The class 9 english CBSE
Difference Between Plant Cell and Animal Cell
Differentiate between homogeneous and heterogeneous class 12 chemistry CBSE
Difference between Prokaryotic cell and Eukaryotic class 11 biology CBSE
Give 10 examples for herbs , shrubs , climbers , creepers
Change the following sentences into negative and interrogative class 10 english CBSE
Write a letter to the principal requesting him to grant class 10 english CBSE
The Equation xxx + 2 is Satisfied when x is Equal to Class 10 Maths
Why is there a time difference of about 5 hours between class 10 social science CBSE