“From Megasporangium to Embryo Sac: The Journey of the Female Gametophyte in Angiosperms”
Megasporangium: Structure and development of Ovule What is megasporangium? In angiosperms , the ovule itself functions megasporangium . It is the structure that produces megaspores, which develop into the female gametophyte(embryo sac). The ovule is located inside the ovary of the flower. 🌱 Structure of a typical ovule A typical angiosperm ovule consists of: 1️⃣ Funiculus Stalk that attaches ovule to placenta. 2️⃣ Hilum Junction between funiculus and ovule body. 3️⃣ Integuments Protective layers surrounding nucellus. Usually two (bitegmic). Leave a small opening called micropyle. 4️⃣ Micropyle Opening through which pollen tube enters. 5️⃣ Nucellus Central mass of parenchymatous tissue. Functions as megasporangium. 6️⃣ Chalaza Region opposite to micropyle where integuments meet. 🌺 Development of Ovule Ovule develops from a small mass of meristematic tissue on placenta. Steps: 1.A hypodermal archesporial cell differentiates in nucellus. 2.It divides periclinally into: Primary pariet...