Nyctinasty, the mechanism by which plants close up its leaves/flowers at night and open up in the morning. Thank you to pineapple for using it recently. Learn something everyday.
I have a lot of expired birth control pills (don't ask) and have had good results with them when used with houseplants. I've revived seemingly dead plants with a couple of these pills around the root zones. So I decided to test it out on aquatic plants. I put 1/4 of the pill in a 29G tank. The following day, NOT A SINGLE PLANT opened up their leaves. HA HA HA HA HA
This is definitely one of the more humorous and surprising things I have ever encountered in this hobby. Over the next several days, the spots on the Amano shrimps intensified and appeared MUCH MORE numerous near the head region.
The active ingredients in these birth control pills are norgestimate and ethinyl estradiol. I went on Google and did some research on these chemicals to see if there have been any published studies involving them and plants. Two interesting articles popped up: one describing the use of birth control pills to promote the growth of a certain controlled substance and the other detailed how high levels of norgestimate in aquatic systems affect, among other things, the transport of Ca and some other minerals in animals (and plants too I think?). A search on "nyctinasty" reveals that its mechanism involves turgor pressure.
I am not a botanist or am very familiar with the anatomy and physiology of plants. Would someone more fluent in the field shed some light on this interesting phenomenon?