What is a possible explanation to why there are more pollen grains produced by an anther than ovules produced?

Question

by one ovary?

Answer 1

Plants and their pollinators have co-evolved because plants offer a reward for the repeated visitation of 'their' pollinators. In flowering plants pollen has evolved two roles: carrier of sperm genome and food reward for pollinators. This requires they make pollen to cover both needs.

Both bees and beetles consume large quantities of pollen as their protein source. The plants seeking these pollination partners often signal the presence of pollen by visual and olfactory cues. Yellow food guides and showy stamens   advertise pollen as a food source.

http://www.amjbot.org/cgi/content/full/9...

Pollen has its own scent, distinct from the whole flower aroma, in some species. to signal pollinators. Pollen eating insects are attracted by the smell of pollen to the mature flowers.

http://www.jstor.org/pss/2446264

" odour ... was the primary and overriding cue used by bees to select pollen."

http://www.sciencedirect.com/science?_ob...

Bee pollen collection is to make  a protein-rich food to feed the larvae.

http://ag.arizona.edu/pubs/insects/ahb/i...

Answer 2

Consider this by using humans in comparison. Women produce one ovum per every time meiosis (s*x-cell production) occurs in the cells. Men on the other hand produce four sperm cells. The reason only one are produced in women is actually because 4 new eggs are produced, but only one has sufficient cytoplasm to survive. The cytoplasm division was fixed in favour so that one cell would have a lot. Women don't need so many eggs. They stay within the ovaries and wait for sperm to come along, they don't go anywhere. However, sperm cells, with the cytoplasm delivered equally to all of them, as they only need this much cytoplasm, are the ones looking for an egg to fertilize. They venture out into 'foreign places'. It's the same idea with pollen. It's going to go on a mission to pollenate more flowers. More ovules aren't necessary, they aren't going anywhere.

I apologize if my explanation wasn't clear enough, but I hope it helped.

Answer 3

The possible reason why there are more pollen grains produced than the ovary, is to ensure  fertilization. When there are more pollen grains produced, there is a greater chance for pollination.