Which of the following order is correct about the wall layers of microsporangium?
1
Epidermis → Endothecium → Middle layers → Tapetum
2
Tapetum → Epidermis → Middle layers → Endothecium
3
Endothecium → Tapetum → Epidermis → Middle layers
4
Epidermis → Endothecium → Tapetum → Middle layers.