1. SEXUAL REPRODUCTION IN FLOWERING PLANTS
CHAPTER 1
SEXUAL REPRODUCTION IN FLOWERING PLANTS

2. flowers are morphological and embryological marvels and the sites of sexual reproduction

3. PRE-FERTILISATION: STRUCTURES AND EVENTS
In the flower the male and female reproductive
structures, the androecium and the gynoecium differentiate and develop.
the androecium consists of a whorl of stamens
representing the male reproductive organ and the gynoecium represents
the female reproductive organ.

4. Stamen, Microsporangium and Pollen Grain
typical angiosperm anther is bilobed with
each lobe having two theca, i.e., they are dithecous
four microsporangia

5. Structure of microsporangium
Microsporogenesis
The process of formation of microspores from a pollen mother
cell through meiosis

6. pollen grains represent the male gametophytes
Pollen grains are rich in nutrients

7. The gynoecium represents the female reproductive part of the flower.
The Pistil, Megasporangium (ovule) and Embryo sac
The gynoecium represents the female reproductive part of the flower.
multicarpellary
monocarpellary

8. syncarpous).
apocarpous

9. The Megasporangium (Ovule)
The ovule is a small
structure attached to the placenta by means of a stalk called funicle.

10. Megasporogenesis
The process of formation of megaspores from the megaspore mother cell is called megasporogenesis

11. Autogamy- pollination is achieved in the same flower
Chasmogamy- Oxalis
Cliestogamy- Oxalis

12. Xenogamy- between different plants
Geitonogamy- pollen from the anther to the stigma of another flower of the same plant.
Xenogamy- between different plants

13. Agents of pollination Abiotic and biotic
Wind pollination- pollen grains are light and non-sticky. Well exposed stamens
Water pollination- long ribben like, mucilage covering

14. Animal pollinated Pollen robbers
Flowers are large, colorful, fragrant and rich in nectar.
Small flowers are clustered into inflorescence
Yucca and moth
Pollen robbers

15. Outbreeding devices
Continued self pollination result in inbreeding depression.
Receptivity is not synchronised
Anther and stigma are placed in different positions
Self incomactibility
Unisexual flowers

16. Pollen grains are shed at two celled stage
Pollen pistil interaction
If the pollen is of the right type pistill will allow germintaion- communicate through chemicals
Pollen grains are shed at two celled stage

17. Artificial hybridisation
Emasculation and bagging

18. Double fertilization
syngamy and triple fusion- embryo and edoseprm

19. Post fertilization changes’
Endosperm, embryo development, maturation of ovules into seeds and ovary into fruit
Free nuclear endosperm
Endosperm is completely used up- pea, groundnut
Endosperm is not completely used up- coconut, castor

20. embryo

21. seed A fertilized ovule Albuminous and non albuminous seeds
Remnants of nucellus- perisperm

22. Fruit A mature ovary Pericarp- walls of fruit from integuments
dormancy
False fruits
Parthenocarpic fruits

23. Apomixis and Polyembryony