To start with
every organism has fixed number of chromosomes in each cell of the body, which in deploid organisms we call 2n (two sets of ) chromosomes. During sexual reproduction when gametes are formed the two sets seperate , thus the gametes have only one set of chromosomes, n. When the two gametes fuse (like pollen grain and ovule , or sperm with ovum) we again get a deploid cell (n+n=2n) called zygote. This after repeated cell division and organ formation form the individual. plant or animal. That is how we get half chromosomes from father and half from mother.
Every new cell formed here after cell division is deploid. And then we say race continues.
During the cell division every chromosome is attached to a spindle by a fibre called spindle fibre. This pulls the chromosome to pole when the chromosomes are in dividing state.
If the chromosome fails to attach to the fibre it fails to get incarporated in new cells formed, either gamete or normal body cell. thus cells produced are abnormal because they miss one or more chromosomes.
Sometimes the chromosomes in deviding state fail to detach from one another and the whole lot go to one cell while the other cell gets nothing. the one which gets nothing perishes, while the one get both sets is now abnormal gamete having 2n number of chromosomes instead of n. When this gamete fuses with other gamete of n type the zygote gets 3n which is called as polyploid.
this can happen in the body cells also. like in plants when the cells are dividing during growth the chromosomes duplicate in each cell and seperate into half. so each cell gets 2n. But sometimes if the duplicated chromosomes are not seperated, -abnormal- then the resulting cell gets 4n because chromosomes are already duplicated. such cell when form further cells they all will have 4n chromosomes. polyploid cell from where new shoot formed will be polyploid.
many a times it may result into triploi--3n, tetraploid--4n, pentaploid--5n, hexaploid--6n, hectaploid7n, octaploid 8n ect.
polyploi result into gigantism that is big flowers, leaves etc.
when this occurs naturaly it is seen as what is seen in your Lily flowers.
This phenomenon is called as chromosome abberation
pl search googal for elustrations.
Dear Botanists and Zoologists pl forgive me for the use of crude language and avoiding the bumbarding words.
--- On Sat, 11/6/11, shubhada nikharge <shubhada...@yahoo.co.in> wrote: