Is it usual for a plant's ovule to produce multiple seeds?

When the ovule is fertilized by the pollen, am I right to think that just a single seed results?

If so, can the ovule be fertilized by yet more pollen?

If so, is this species-specific, or does the quantity of seeds depend on growing conditions?

 

Hi Simon. Yes I think you are right.

I have had a Google and it seems that you have an oviary, and within that oviary you can have many ovules. The ovules are attached to the placental wall of the ovary through a structure known as the funiculus, the plant equivalent of an umbilical cord. Each ovule, I believe, can only produce one seed. But the oviary itself can produce many seeds because it can contain many ovules. A pea pod is an example of a developed oviary, and the peas inside are the seeds that have formed from the ovules within the oviary.

Many sources that I have looked at quote the number of seeds per ovule. But the figure is always less than one, often between 0.7 and 0.3. What this means is that some ovules in a fertilised oviary never produce seeds.

When a flower is first pollenated the pollen lands on the style (the tip of the female part) it then creates a small tube to allow it to reach down to the oviary and from there to the ovules. I suspect that once a flower has been pollinated there is a mechanism that closes the tube so a flower cannot be successfully pollinated more than once.

However some flowers have more than one oviary, and many plants have more than one flower in the flower head. For instance each grain of corn on a head of maize comes from a seperate flower. So each grain of corn is the result of a seperate act of pollination.