Pollination and sexual reproduction in plants

Hi,

Pollination involves flowers and pollen grains. The agents of pollination could be insects such as bees, ants, bats and other animals that visit flowers to get their food- pollen grains and nectar.

After the pollen grain is successfully transferred from the anther to the stigma, fertilisation process will kick in. This process is different from that in animals as the pollen grain germinates and grows a pollen tube will allows the male gamete to travel through the tube to the ovule.

Flowers go to great lengths to avoid self-fertilisation and prefer cross-fertilisation. It is fascination to see this processes employed in the different species of flowering plants.


Watch these two videos to clarify these concepts.










Cheers

Lesson 10: Cell division-mitosis and meiosis

Hi,

This is a very good revision material to view. concepts covered include:

• cells divide to increase numbers for growth, repair and reproduction
  
• cell organelles-mitochondria, chloroplast, nucleus, cell membrane
• specialised cells-red blood cell, nerve cell, pollen, guard cell, palisade cell, xylem cell,
• 1 billion cells per hour are replaced in your body by cell division
• blood cells by bone marrow by mitosis
  
• skin cells 100 million per day by mitosis
  
• zygote, 1 cell, grows into baby within 9 months by mitosis
• photographs on mitosis in onion shoot and root tip showing mitosis
• meiosis- in testis, ovary, anther
• fertilisation restores the diploid number in zygote
• mitosis ( 2n--> 4n--> 2n-->2n)
• meiosis (2n--> 4n-->2n-->n)
  
• the sex of child is determined at the point of fertilisation
• fertilisation with y-carrying sperm results in male, fertilisation with x-carrying sperm results in female child.
• meiosis occurs in anther producing pollen, in testis producing sperm, in ovary producing ova, ( or ovule in plant).
  
• self fertilisation less variation than cross fertilisation in plants
• short questions
  

Mitosis and Meiosis

View more OpenOffice presentations from Dr samuel Aylward.

Cheers