What are characteristics of megasporangium and female cone of Pinus?
The megasporangium is located on female cone. Each female cone is composed of large number of spirally arranged scales which are woody in texture. At the base of each scale is an ovule. An ovule is actually a megasporangium which is protected by one additional layer called integument. Each megasporangium has a single diploid megaspore mother cell. The megaspore mother cell divides by meosis to produce four haploid megaspores.
How pollination and fertilization occur in Pinus?
During pollination the pollen land directly on the ovules. Only some pollens are able to form pollen tubes through which male gametes are transferred to the embryo sac for fertilization purpose. More than one egg can be fertilized to form several zygotes, but one zygote usually survives to form a single embryo.
What happens after fertilization in Pinus?
After fertilization the ovule becomes the seed. The seed now contains an embryo along with some stored food material. The seed upon germination shall give rise to new sporophyte plant.
What are angiosperms?
Angiosperms are the flowering vascular plants. The term Angiosperms literally means “enclosed seeded”. In these plants fertile leaves bearing ovules are folded and joined at the margins to form ovaries in which seeds are enclosed. The ovary after fertilization is changed into a fruit.
What is a flower?
A flower is a modified shoot which consists of a pedicel, a thalamus or torus, and floral leaves i.e., sepals, petals, stamens and carpels.