Avoiding self-fertilization

[drosera]

Hi,

I asked this question elsewhere a couple of years ago, but no one could give me an answer. I thought I'd try again here, and see if there's been a change.

For those plants that cannot self-pollinate;

Beyond structural barriers against self-fertilization, how can a plant differentiate it's own genetic material from that of other plants of the same species to ensure cross pollination? (Hope I said that all right

Take care!

Chris

 

[schloaty]

this is a guess. this is only a guess. if this had been a real answer, it would be right.

Perhaps they have a chemical "tag" on their pollen and Pistols. If the chemical tag is a match, then the pollen is rejected.....just a thought. Hope someone knows for sure.

 

[Vic Brown]

Besides physical barriers, temporal barriers (ie pollen ripens at a different time to stigma receptability) and dioecism (plants all male or all female as in Neps), self-incompatabilty or xenogamy in flowering plants is often gametophytic.
If a pollen grain (male gametophyte) has the same gene as is found in style (sporophytic tissue), pollen tube growth is halted, and no germination occurs. This usually involves a single gene, but some examples of multiple genes known. Usually there are many alleles of the gene in a population and self pollen will always have a match with one of the two possible alleles in the style tissue. Also, closely related individuals are more likely to have matching alleles between pollen and style than will less closely related individuals and hence crosses between closely related individuals are likely to be less productive too.

So Scloaty's answer is almost correct, the 'chemical tag' is genetic.

Vic