I think at least one of their functions is to conserve moisture.

I was told that it was a defense mechanism mainly deterring the progress of insects.

Randy

Hmmm. I googled it, but found nothing. I was just curious because I was wondering if touching the stems and damaging the hairs would hurt my plants at all.

What an interesting question. I had never really thought about it myself. I know that some hairs are "glandular" and secrete stuff. ("Stuff" is about as technical as I can get with tomatoes!) In my other life I'm a research librarian, so lemme see what I can find...

Mary

Surface area to increase photosynthesis????

They turn into roots if you plant your tomatoes deeply (I think, lol) Plus check out another thread here at the forum they could be a possible bug deterent very interesting developement.

From what I can find, many researchers are still trying to fully understand what the trichomes (hairs) do. They can secrete steroidal glycoalkaloids that seem to function as a toxic defense, but much still is unknown.

There is a major study underway at the Michigan State University, the University of Michigan, and the University of Arizona to explore the start-to-finish "chemistry and function" of the compounds.

More: http://www.trichome.msu.edu/about/overview_continued.html

Mary

Here is a link that might be useful: The Solanum Trichome Project

I heard it helps keep things that can float through the air (like maybe viruses, bacteria) from getting too close. Like your nose hairs, they help filter bad things before they can contact the actual plant skin and do damage. That's juat what I heard, I don't remember from where. I try not to manhandle the stems for that reason.

Hi first time posting and I'm wondering the same thing. I'm doing an experiment where I took two clippings thesame size from thesame plant in the same potting soil rooted them inside, water the same time and same amount everyday. I transplanted them into larger pots, although one pot is a little taller then the other its level with the same amount of potting mix in both. Now after seeing stuff about putting quartz crystals in the pot on the internet and seeing the difference in pictures, I wanted to see for my self. A month later the one with quartz is much bigger flowering and noticeably healthier and covered in those white hairs.. The other still has hairs but not nearly and long or as much

You will find that most places say "the hairs will turn into roots if buried under the soil." This is false. The hairs do not turn into roots, the roots form and emerge from a group of cells much deeper within the plant tissue.

From what I have read, and what I understand about plants, the hairs are most likely used for defense from predation, whether by insects or larger herbivores. Some of them do have glands that secrete compounds that make the tomato plant smell...tomatoey (I'm sure they serve a different function beyond smell, though).

This is a cross section of an emerging adventitious root. The hairs on a tomato are attached to the epidermal cells whereas the root is formed from pericycle cells.

I think Zack is correct.

Plants without hair can grow roots too. I root a lot of plants from cuttings, with no hair.

I used to think that it is part of breathing and exchanging mechanism. ( get air, moisture,).
It is interesting that those hairs appear when it warms up. As have noticed the other day. Maybe it is a wrong observation.

Seysonn, that is interesting. I had never thought about it but who knows? I think it is safe to say that we know more about the surface of the moon than we do plants right here on earth lol.

I was always taught that gas exchange happened in the spongy mesophyll of leaves, it would be interesting if trichomes also played a role.

78 years old and this has never crossed my mind before.Very interesting question.

Here's MY guess.....the hairs are there to protect the main stem from getting burned up by the sun !!!

And I'm stickin' to it.

Interesting !
Yesterday I was observing. Even leaves on some varieties have hairs.

Maybe they have more than one purpose. Surely they would deter some insects (not hornworm!), but they also might provide shade for the stem and leaves.

I have frequently noticed that small flying insects have perished stuck to my tomato plants.

I know once the hairs appear on my tomatoes I ditch the slug bait. I don't think the slugs like going against the grain of the tomato stem hairs.

As socks says, maybe they have more than one purpose. It's also entirely possible that the hairs have no important purpose, i.e., they did have an important function further back in the evolutionary line, but hairy stems are just not burdensome enough to have been selected out since.

Personally, I think that they're probably useful to prevent predation on the parts protected, and like many, many hairs all over all the branches of life on earth, they may serve to disperse secretions. Not sure about conservation of water. I know that many plants native to dry areas have hairy leaves, but tomatoes generally don't.