Tomato flowers that close at night

[FredB]

I have noticed that flowers of Solanum habrochaites and S. peruvianum close at night and reopen the next morning. Flowers from regular tomatoes stay open at night. S. habrochaites and S. peruvianum both have large, showy flowers with exserted stigmas, signs that they are pollinated by an insect, probably a bee. Maybe they close at night to prevent damage from night-pollinators such as moths?

Fred

[bower]

I think this is a fairly uncommon trait in flowering plants although I may be wrong. I know it from one species of thistle Carlina acaulis. These are said to close their flowers when rain is imminent, ostensibly to 'protect the pollen' according to sources found by google.

I have the Carline thistle in my garden (perennial) and I have seen the flowers open and close in the dead of winter. I mean, flower structure remaining on the plant, was activated to open the flower in response to bright sunlight in a February when snow levels were low and exposed the completely brown, dead, aboveground parts of the plant. It appears that the opening and closing is entirely mechanical in this case, activated by bright sunlight, but certainly no messaging systems or biochem of any kind involved. There was no rain to cause them to close again nor relative humidity in temps well below freezing, so it was all about the light/darkness trigger and I'm not sure how that works in the absence of living parts.

Don't know if any experiments have actually been carried out - whether a closing flower had better reproductive success than a stay open flower, or whether the 'protect pollen' notion is a conjecture. Anyway it is the light/darkness factor so cloudiness prior to rain that caused them to close, not as such a response to prevent pollen from being washed away? by wet weather.

[Uncle Doss]

I believe that most pumpkins open their blooms in the morning and close them in the evening

[bower]

Originally Posted by Uncle Doss

I believe that most pumpkins open their blooms in the morning and close them in the evening

Right! I knew I had seen it somewhere else, zuchinni also open and close their flowers until they're done. But they only last a couple of days at most.
There always seems to be a 'closing' of every kind of flower, once it is pollinated or 'spent'. It just takes tomatoes a long while - two weeks is typical at our temperatures here.