Give ONE illustration example of a mechanism to prevent self-pollination.?

Question

can ANYONE help ME with that...dont GET it...?

Answer 1

Dichogamy in the flowering plants

In the context of the flowering plants (angiosperms), there are two forms of dichogamy: protogyny—female function precedes male function—and protandry—male function precedes female function.

The meaning =

In a bisexual flower = either Stamens mature and disperse their pollen and only then stigma matures to receive pollen from OTHER flower .( Protandry)

OR

Pistil matures first and the stigama receives pollen from OTHER MATURE  flower , only then the stamens come to maturity .

click on the links ==

http://en.wikipedia.org/wiki/Heterostyly

http://www.life.uiuc.edu/help/digitalflo...

http://www.life.uiuc.edu/ib/335/Breeding...

http://www.inhs.uiuc.edu/~kenr/prairieph...

http://plantandsoil.unl.edu/croptechnolo...

http://www2.dpi.qld.gov.au/images/3521.g...

Answer 2

Well, stamens and carpels can be situated in the different flowers (birches) or even in different plants (for example willows are like this)

Stamens and carpels can grow at different times.

Stamens can be so small, they cannot touch the tip of the carpel.

Sorry, there was four examples. :)