Do junipers really "drink" water through their foliage?

[Clicio]

... “earth magic”
I suppose it will get moisture from foliage when it can, but it doesn’t really “need” to because your yard holds moisture better than a pot because it’s bigger

Yes, but I am talking here specifically about trees already in pots. And there are some people that advocate for the technique.

 

[BrianBay9]

I remain dubious. Trees have structures designed to efficiently take up water and nutrients. They're called roots. Stomata are designed for gas exchange. Yeah, maybe moist gases are better than dry. Maybe trace amounts of ferts can get in stomata. But roots sustain the tree.

 

[IzzyG]

The current prevailing theory(although there has been recent challenges to it) revolves around the cohesion tension theory. The idea is basically the stomata is flexible when there is sufficient water and opens up (levels of CO2 and temperature also plays a part) which leads to gaseous exchange.

Photosynthesis occurs via combination of carbon dioxide and water and results in carbohydrate and oxygen

6CO^2 (carbon dioxide) + 6H^2O (water)

becomes

C^6H^12O^6 (carbohydrate) + 6O^2

The exchange of gaseous (carbon dioxide for oxygen) via transpiration creates tension gradients that pulls water from the roots up towards the leaves against gravity. Misting the foliage mass seems to cause a temporary disruption of transpiration (shutting it off for a moment) which allows the system to catch up on any shortfall. In essence, cutting back the demand for water until the supply side catches up.

Recently, the introduction of multi-force theory of water acquisition(U. Zimmermann et al. 2004) introduced other models but I don’t believe a direct transpiration-caused uptake is mentioned.

I know Bjorn is a huge proponent of misting foliage while Ryan is completely against it(except for a few specific situations). Both have world class show trees

 

[leatherback]

Junipers can take up a large part of their daily water needs through their foliage.

It is a very common method for plants to take up water, and some species (Epiphytes) pretty much completely rely on it. It is well-studies for many species and many situations.

 

[Clicio]

Junipers can take up a large part of their daily water needs through their foliage.
It is a very common method for plants to take up water....

Yes, but not in the evening.
Fungal issues are a real problem around here.

 

[chicago1980]

Can you post a photo of the tree?

If he is doing this practice and seeing great results.

 

[Clicio]

Can you post a photo of the tree?

If he is doing this practice and seeing great results.

Yes sir.
Here is the photo from the day I got it.

 

[Baku1875]

I'm trying to find a good answer, and I'm reading two different studies at the moment

Branch water uptake and redistribution in conifers....
https://www.nature.com/articles/s41598-021-00436-x

Stomatal Size, Speed, and Responsiveness Impact on Photosynthesis and Water Use Efficiency1,[C]
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3982722/

I know that moisture on the leaves of most trees including conifers will slow down and HALT transpiration which will prevent moisture loss as well as slow down photosynthesis by triggering constriction of stomata.

This is what Ryan Neil preaches (misting root-compromised/repotted/heavily bent junipers in late summer and gradually moving them from shade +misting, to partial shade + misting, partial shade withoout misting, then full sun with misting, and finally full sun without misting)

According to the first study (branch water uptake) branches and bark in various species of conifers are responsible for a winter survival mechanism to absorb and relocate moisture to parts of the tree as well as assist in repair from frost related embolism in the xylem and provide the necessary moisture for spring growth. From skimming the study, it appears that the mechanism becomes active in late winter into may to take advantage of melting snow..

"Both conifer species under study were demonstrated to take up water over the branch surface and to redistribute absorbed water over significant distances within the crown. This confirms previous studies suggesting branch/foliar water uptake in conifers3,23,26,27,28 and proves for the first time that water can be redistributed over large distances from branches towards the trunk and side branches under winter conditions. However, our study shows that the extent of water absorption and redistribution is species-specific."

"It is thus likely that melting snow is an important source for branch water uptake, and results on the deciduous species L. decidua clearly indicated bark to participate in the process of water absorption. Absorbed and redistributed water may contribute to the repair of winter xylem embolism as well as restore water reservoirs prior to the vegetation period."

I would be curious to find out specifics about junipers, because something tells me that it would be a similar mechanism.

 

[Clicio]

I would be curious to find out specifics about junipers, because something tells me that it would be a similar mechanism.

As soon as you find any articles about junipers, please post the link here.

 

[PowerTap]

Yes sir.
Here is the photo from the day I got it.

View attachment 489636

That sir, is an impressive mustache.

 

[nuttiest]

I think you can rely on this to happen during dew point, but not on demand later in the day.

 

[leatherback]

Foliar water uptake as a source of hydrogen and oxygen in plant biomass

Introductory biology lessons around the world typically teach that plants absorb water through their roots, but, unfortunately, absorption of water through leaves and subsequent transport and use of this water for biomass formation remains a field limited mostly to specialists. Recent studies...

www.biorxiv.org

in the case of well-watered Cryptomeria japonica, hydrogen and oxygen incorporated into new leaf cellulose in the rainy season derives mostly from foliar-uptake water, while that of new root cellulose derives mostly from root-uptake water, and new branch xylem is somewhere in between. Abandoning the assumption that these elements are supplied from soil water alone may have vast implications in fields ranging from isotope dendroclimatology, silviculture, to biogeochemistry.

https://onlinelibrary.wiley.com/doi/full/10.1111/pce.13439

At the end of Stephen Hales' renowned publication, Vegetable Staticks (1727), he concludes that water absorbed through leaves is “… insufficient its small quantity is towards making good the great demands of perspiration.” However, we demonstrate that FWU is prevalent across species and biomes, which the physical requirements for it to occur happen routinely, and that it can serve as a critical source of water for metabolic function. However, there are still many unanswered questions about FWU that require creative and interdisciplinary experiments. The undeniable ubiquity of this fundamental plant process highlights a need to understand FWU as intricately as we understand processes such as root water absorption, xylem flow, and transpiration.

 

[Clicio]

Foliar water uptake as a source of hydrogen and oxygen in plant biomass

Introductory biology lessons around the world typically teach that plants absorb water through their roots, but, unfortunately, absorption of water through leaves and subsequent transport and use of this water for biomass formation remains a field limited mostly to specialists. Recent studies...

www.biorxiv.org

in the case of well-watered Cryptomeria japonica, hydrogen and oxygen incorporated into new leaf cellulose in the rainy season derives mostly from foliar-uptake water, while that of new root cellulose derives mostly from root-uptake water, and new branch xylem is somewhere in between. Abandoning the assumption that these elements are supplied from soil water alone may have vast implications in fields ranging from isotope dendroclimatology, silviculture, to biogeochemistry.

https://onlinelibrary.wiley.com/doi/full/10.1111/pce.13439

View attachment 489748
At the end of Stephen Hales' renowned publication, Vegetable Staticks (1727), he concludes that water absorbed through leaves is “… insufficient its small quantity is towards making good the great demands of perspiration.” However, we demonstrate that FWU is prevalent across species and biomes, which the physical requirements for it to occur happen routinely, and that it can serve as a critical source of water for metabolic function. However, there are still many unanswered questions about FWU that require creative and interdisciplinary experiments. The undeniable ubiquity of this fundamental plant process highlights a need to understand FWU as intricately as we understand processes such as root water absorption, xylem flow, and transpiration.

Thanks for posting @leatherback , very interesting indeed.

 

[Paradox]

It isn't surprising they can uptake water through the foliage.

However I don't think I would want to rely on it during the hot summer as a sole source of water for my trees.

Bromeliads aside, it does appear to be very efficient for most vascular plants.

 

[Paradox]

It isn't surprising they can uptake water through the foliage.

However I don't think I would want to rely on it during the hot summer as a sole source of water for my trees.

Bromeliads aside, it does appear to be very efficient for most vascular plants.

EDiT
It *does not appear to be very efficient

This phone sometimes...

 

[jerzyjerzy]

Another thing is - there is no barrier stopping the water drops formed on needles during misting, from falling onto the soil in the pot. I bet the soil gets moist as well, so it is also a point of water intake. The soil can even get wet, depending of the actual duration of misting.

 

[Gabler]

My hunch is this: Nature doesn't normally just "do things" for no reason. Junipers have foliage year round because they NEED it year round. They may need it to get whatever they need , anyway they can get it. They normally come from fairly harsh environments where resources are scarce. Getting water and nutrients through needles, roots or even bark may be an evolutionary adaptation. .............. Or not.

I think it bears mentioning that nothing in nature is ever done with a purpose, including, in this case, the evolution of species by natural selection. Of course, through natural selection, things which are useful tend to remain, and things which are not useful tend to disappear. In that sense, I suppose you could describe certain adaptations as “purposeful,” to the extent they are useful in passing genes to the next generation, but it’s an anthropomorphic way of describing the phenomenon and therefore misleading.

All things in nature happen randomly in proportion to their probability of occurring, including gene mutations and gene selection from parents. When genes randomly vary, those genes which prevent themselves from being passed on to offspring are less likely to be replicated, and they might eventually die out, or the environment could change, rendering them harmless or useful, allowing them to persist. Evolution is usually, but not always, the demise of the least fit.

Occasionally, a very harmful trait will appear in an individual with a bunch of other traits that compensate for the harmful trait, so the harmful trait is passed on. Sometimes, an incredibly useful trait appears in an otherwise unfit individual, and that trait is lost. Sometimes, luck may favor an unfit individual over a fit one. A seed with genes statistically most likely to be passed on to offspring may nonetheless by chance be eaten by squirrels before germinating. It is likewise very common for traits which are not useful but also not harmful to be passed to offspring. There isn’t enough selective pressure to kill them off, so they persist even though they serve no purpose.

 

[Joe Dupre']

I think it bears mentioning that nothing in nature is ever done with a purpose, including, in this case, the evolution of species by natural selection. Of course, through natural selection, things which are useful tend to remain, and things which are not useful tend to disappear. In that sense, I suppose you could describe certain adaptations as “purposeful,” to the extent they are useful in passing genes to the next generation, but it’s an anthropomorphic way of describing the phenomenon and therefore misleading.

All things in nature happen randomly in proportion to their probability of occurring, including gene mutations and gene selection from parents. When genes randomly vary, those genes which prevent themselves from being passed on to offspring are less likely to be replicated, and they might eventually die out, or the environment could change, rendering them harmless or useful, allowing them to persist. Evolution is usually, but not always, the demise of the least fit.

Occasionally, a very harmful trait will appear in an individual with a bunch of other traits that compensate for the harmful trait, so the harmful trait is passed on. Sometimes, an incredibly useful trait appears in an otherwise unfit individual, and that trait is lost. Sometimes, luck may favor an unfit individual over a fit one. A seed with genes statistically most likely to be passed on to offspring may nonetheless by chance be eaten by squirrels before germinating. It is likewise very common for traits which are not useful but also not harmful to be passed to offspring. There isn’t enough selective pressure to kill them off, so they persist even though they serve no purpose.

I didn't mean "do things" in a literal or purposeful way. It was more of a philosophical comment on how nature works. Actually, there isn't an actual "thing" as nature. It's just a description we humans use for the natural world.

 

[leatherback]

I think it bears mentioning that nothing in nature is ever done with a purpose, including, in this case, the evolution of species by natural selection. Of course, through natural selection, things which are useful tend to remain, and things which are not useful tend to disappear. In that sense, I suppose you could describe certain adaptations as “purposeful,” to the extent they are useful in passing genes to the next generation, but it’s an anthropomorphic way of describing the phenomenon and therefore misleading.

All things in nature happen randomly in proportion to their probability of occurring, including gene mutations and gene selection from parents. When genes randomly vary, those genes which prevent themselves from being passed on to offspring are less likely to be replicated, and they might eventually die out, or the environment could change, rendering them harmless or useful, allowing them to persist. Evolution is usually, but not always, the demise of the least fit.

Occasionally, a very harmful trait will appear in an individual with a bunch of other traits that compensate for the harmful trait, so the harmful trait is passed on. Sometimes, an incredibly useful trait appears in an otherwise unfit individual, and that trait is lost. Sometimes, luck may favor an unfit individual over a fit one. A seed with genes statistically most likely to be passed on to offspring may nonetheless by chance be eaten by squirrels before germinating. It is likewise very common for traits which are not useful but also not harmful to be passed to offspring. There isn’t enough selective pressure to kill them off, so they persist even though they serve no purpose.

genetics, evolution and natural selection 101s in a short post. Well done!

 

[Gabler]

I didn't mean "do things" in a literal or purposeful way. It was more of a philosophical comment on how nature works. Actually, there isn't an actual "thing" as nature. It's just a description we humans use for the natural world.

I don’t mean to call you out. You mentioned you had a hunch, so I figured I’d offer what insight I could bring to the table from my time studying human evolution in my anthropology coursework in undergrad. I’m far from an expert, but I‘m sufficiently well-informed to offer some useful context on an internet forum.

I agree that as a shorthand, “purpose” is close enough to “well suited to the proliferation of a gene.” However, in this context, that analogy breaks down. You can’t infer a “purpose” from a trait’s mere existence. Some traits just exist because they aren’t detrimental enough to be selected out of the gene pool.

The human spine, pelvis, and knees, for example, are very poorly adapted to bipedal locomotion. That’s why old people always have back, hip, and knee pain. The back, hips, and knees wear out much sooner on average than other joints. It’s also why women die in childbirth. The pelvic floor has to support the weight of our guts, but it also has to be wide enough for a human head to pass through. Too wide, and you end up with hernia and/or prolapse. Too narrow, and the baby can’t fit through. The skeletal structures were never designed for humans walking upright. We just adapted quadrupedal structures to upright walking, and they work well enough that we haven’t gone extinct yet.