Do garden plants take up water through leaves?

[John Robertson]

I'm told by some that plants don't take up water through the leaves.

While I can believe that (how would they suck up the water anyway?), how does female dogs pissing on weeds work to kill them?

And roundup?

[hubops]

Wrong group - this is Home Repair where only American politics is ranted. John T.

[Dean Hoffman]

A search for 'plants absorb herbicides" should help answer you.

There's this. The short answer is leaves can absorb a small amount of water. Most of it comes in through the roots. More here.

[micky]

I've always wondered if people can absorb liquids through their skin.

Skin moisturers are common and women like them, but my skin at least seems pretty much waterproof.

And they have medicinal and antibioitic creams but I thought they smelled good to germs and the germs had to crawl to the surface to get poisoned.

[angelica...]

God, I hope that's a joke.

Cindy Hamilton

[Tekkie©]

On Wed, 22 Sep 2021 12:56:54 -0400, micky posted for all of us to digest...

Yes, they can. One example is if you hands are in water the pads in your finger tips pucker up.

Here is link:

[Tekkie©]

On Wed, 22 Sep 2021 12:56:54 -0400, micky posted for all of us to digest...

Some more research for you:

[gfretwell]

Some plants do absorb water from the foliage but most get the majority of it from the roots. That still doesn't mean they are not absorbing things from the foliage tho. That is why herbicides work on them. Roundup inhibits the enzyme EPSP and they have figured out how to bypass that for the crops that laugh at Roundup. I assume they looked at plants that have a natural resistance to it and isolated that gene. We have lots of plants here Roundup won't touch.

[micky]

Good to know. Your link is a good one. I guess I'll have to stop dumping on skin moisturizer.

But with my new-fond knowledge, I think you're wrong about finger tips.

used to think that water moved into the outer layers of your skin and caused it to swell. The swelling made a larger surface area, which caused the skin to later wrinkle.

Now we know that pruney fingers are caused by shrinking blood vessels. When you soak in water, your nervous system sends a message to your blood vessels to shrink. Your body responds by sending blood away from the area, and the loss of blood volume makes your vessels thinner. The skin folds in over them, and this causes wrinkles.

It?s not fully clear why this happens, but scientists believe this process evolved so you can have a better grip when your hands are wet.

-- Wow, that reason is hard to believe. So many humans died without enough procreating because when their hand were wet they couldn't hold on to a weapon or maybe their food, or their child, or the cliff or tree they were climbing??? Even if you had no way to stay dry in the rain... wait, fingers don't wrinkle in the rain, only in the bath or lake or maybe the sea. So how much time did people spend in the bath that wrinkly fingers and the ability to hold things better could be an evolutionary advantage? And not just an advantage but a big enough advantage that the non-wrinking were overrun by those who wrinkle? (Doesn't everyone wrinkle now? Gooogle didn't answer that, but even if it's not everyone, how is being able to grip when wet a substantial evolutionary advantage? We are land animals.)

There are a lot of pages that claim evolution is the reason:

excerpt is not about evolution: But a century ago, scientists already knew that this curious reaction wasn?t a simple reflex or the result of osmosis. That?s because surgeons learned that if certain nerves to the fingers were cut, the wrinkling response would disappear. Wrinkled fingers, then, are signs of an intact nervous system. Indeed, the wrinkling response has been suggested as a means of determining whether the sympathetic nervous system is functional in patients that are otherwise unresponsive.

This parts is about evolution: It?s extremely difficult to prove that any biological feature is an adaptation, let alone why it may have evolved. But researchers can look for hints, tell-tale clues that indicate that a feature may indeed have evolved as an adaptation.

And then there?s this: wrinkles don?t appear until around five minutes of constant exposure to water, meaning that incidental contact isn?t enough to result in wrinkling, the response only becomes useful in rainy or dewy conditions. And it occurs far more quickly in response to freshwater than seawater, which could reflect the circumstances in which it may have originally evolved in primates. --- so forget that I mentioned sea. How much time did evoving humans spend in lakes or bathtubs?

skin gives a better grip and may have helped our ancestors uproot wet plants when foraging for food, or be more sure-footed in a slippery, wet environment, they say. -- At least these ideas are on the right target, but I wouldn't use my fingertips to uproot plants. Would wrinkly toes help to walk on wet plants, dirt, grasses, and rocks? Isn't it the heel and the area behind the toes that matter a lot more?

My own idea, that things that apes do were helped by wrinkles and that just got passed onto humans because it was there by then, but what is it that apes do that wrinkles would help?

The familiar wrinkles on wet fingers and toes may also have benefited early humans in their first forays into technology, said Tom Smulders, an evolutionary neurobiologist at Newcastle University.

"It might have helped handling tools in wet conditions," he said, such as fixing hunting weapons in the rain, or fishing with harpoons.

One question that remains is why fingers are not wrinkled all the time, even when they are not in water. The answer may be that wrinkling comes at a cost: the loss of sensitivity in our hands, Smulders said.

I'm not against the notion of evolution, but I think sometimes scientists spend too much time trying to think of evolutionary reasons/advantages when lots of things happen by accident or as side effects.

[angelica...]

If you notice a difference (I do), you can always go back to using moisturizer.

Why should soaking in 103 F water cause blood vessels to shrink? I get pruney fingers in the hot tub.

Cindy Hamilton

[invalid unparseable]

micky is a joke. Thought you knew that.

[micky]

I don't know, but a few other pages said pretty much the same thing, and none I found said otherwise.

[micky]

It's amazingly complicated, isn't it. And not just for people, but porcupines too.