These plants that produce necked seed are called gymnosperm. The fruit is not formed because ovary is absent.
- The main plant is diploid and a sporophytes.
- The plants produce two different types of spores micro spore and mega spore, this condition is called heterospory.
- The functional mega spores develop to form a reduced female gametophytes, which remains within mega sporangium.
- Female gametophytes consists of two to five archegonia each having single ovum.
- Each micro spore develops to form a reduced male gametophytes, which consists of stalk nucleus, tube nucleus, two male gametes and two prothalial cells within an elongated pollen tube.
- Fertilisation takes place within sporophytes.
- After fertilisation mega sporangium form seed.
- Seed undergoes epigeal gerimnation and forms new sporophytes plant.
A flower is a modified reproductive branch. A flower consists of four floral leaves. They are sepals, petal, stamen and carpals. The sepals and petals are non-reproductive leaves. The stamen and carpals and reproductive parts of plants.
Stamen: Stamen is male reproductive part of flower. It consists of two parts, anther and filament. Anther consists pollen Sac, which contain pollen grain or micro spores.
Carpels: It is female part of the flower. It consists of three parts stigma, Ovary, and Style. Ovary consists ovules.
Complete Flower: If one or more floral leaves are absent in the flower it is called incomplete flower.
Bisexual Flower (Hermaphrodite): If both stamens and carpels are present in same it is called bisexual flower.
Uni sexual Flower: If a flower has either stamen or carpal it is called uni sexual. If flower has only stamen it is called staminate. If flower has only carpals it is called carpel late.
Monoecious: If staminate and carpel late are present in same plant, this plant is called monoecious e.g. Corn.
Dioecious: If staminate and carpel late flower are present at different plants then these plants are called dioecious. e.g. date palms.
1 blogger:
Great explanation
Post a Comment