LIVE Course for free

Rated by 1 million+ students
Get app now
JEE MAIN 2023
JEE MAIN 2023 TEST SERIES
NEET 2023 TEST SERIES
NEET 2023
CLASS 12 FOUNDATION COURSE
CLASS 10 FOUNDATION COURSE
CLASS 9 FOUNDATION COURSE
CLASS 8 FOUNDATION COURSE
0 votes
67 views
in Biology by (95.1k points)
closed by
(a) Explain the development of female gametophyte from a megaspore mother cell in an angiosperm.
(b) Draw a labelled diagram of a fully developed embryo sac.

1 Answer

0 votes
by (94.5k points)
selected by
 
Best answer
(a) The nucleus of the functional megaspore divide mitotically to form two nuclei which move to the opposite poles, formating the 2-nucleate embryo sac. Two mare more sequential mitotic nuclear divisions result in the formation of the 4-nucleate and later the 8-nucleate stages of the embryo sac. After the 8-nucleate stage, cell walls are laid down leading to the organisation of the typical female gametophyte or embryo sac. Six of the eight nuclei are surrounded by walls and are organised into, the nuclei, called polar nuclei are situated below the egg apparatus in the large central cell. Three cells are grouped at nuclei are situated below the egg apparatus in the large central cell. Three cells are grouped at the micropylar end and constitute the egg apparatus. The egg apparatus, in turn, consists of two synergids and one edd cell. The synergids have special cellular thickenings at the micropylar tip called filiform apparatus, which play an impotant role in guiding the pollen tubes into the synergid. Three cells are at the chalazal end and are called the antipodals. Thus, a typical angiosperm embryo sac, at maturity, though 8-nucleate is 7-celled.
image

Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students.

Categories

...