# How does stuff get into the roots of a plant? **URL:** \ **Category:** Factual Questions\ **Created:** [November 25, 2009, 7:20pm UTC](https://boards.straightdope.com/t/how-does-stuff-get-into-the-roots-of-a-plant/518940 "2009-11-25T19:20:32Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![Inigo\_Montoya](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/inigo_montoya/32/124_2.png) [@Inigo\_Montoya](https://boards.straightdope.com/u/Inigo_Montoya)\ **Post date:** [November 25, 2009, 7:20pm UTC](https://boards.straightdope.com/t/how-does-stuff-get-into-the-roots-of-a-plant/518940/1 "2009-11-25T19:20:32Z")
Do roots take in actual particles of soil which are then dismantled inside the plant? Do plants poop? Or do roots take in nutrients at the molecular level through osmosis? If so, do they “digest” particles of dirt outside of the root before doing so, or do they just get lucky and something breaks down into a molecule they need which then comes into contact with the root? I don’t need the answer all that fast. ---
**Author:** ![Harmonious\_Discord](https://avatars.discourse-cdn.com/v4/letter/h/74df32/32.png) [@Harmonious\_Discord](https://boards.straightdope.com/u/Harmonious_Discord)\ **Post date:** [November 25, 2009, 7:30pm UTC](https://boards.straightdope.com/t/how-does-stuff-get-into-the-roots-of-a-plant/518940/2 "2009-11-25T19:30:53Z")
They uptake water and whatever is dissolved in the water. ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [November 25, 2009, 7:41pm UTC](https://boards.straightdope.com/t/how-does-stuff-get-into-the-roots-of-a-plant/518940/3 "2009-11-25T19:41:20Z")
> [@Inigo\_Montoya](#): > > Do roots take in actual particles of soil which are then dismantled inside the plant? Do plants poop? > > Or do roots take in nutrients at the molecular level through osmosis? If so, do they “digest” particles of dirt outside of the root before doing so, or do they just get lucky and something breaks down into a molecule they need which then comes into contact with the root? plants produce CO2 as a waste product during respiration. Plants produce O2 during photosynthesis. these gases are expelled through the leaves and some stems. mineral salts are dissolved in water which the roots take in through transport processes. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [November 26, 2009, 6:33am UTC](https://boards.straightdope.com/t/how-does-stuff-get-into-the-roots-of-a-plant/518940/4 "2009-11-26T06:33:35Z")
> [@johnpost](#): > > plants produce CO2 as a waste product during respiration. Plants produce O2 during photosynthesis. these gases are expelled through the leaves and some stems. 1. CO2 is also produced in very large quantities by the roots. 2. Huh? What s the relevance of gas exchange to the question in the OP? > [@](#): > > mineral salts are dissolved in water which the roots take in through transport processes. That’s really too simplistic to be correct. There are a lot of biological processes going on that free up nutrients and enable the plants to absorb it. Everything from direct influences of the root hair on nutrient solubility to mycorhizal fungi digesting organic matter and passing the nutrients to the plant root. So it’s correct enough for a layman to say that plants “digest” particles of dirt outside of the root in order to free up essential nutrients Whether a plant is more dependent on passive absorption of nutrients on water, or more dependent on nutrients that have been actively freed up by biological processes associated with the plant itself depends on what type of soil it’s growing in. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [November 26, 2009, 8:05am UTC](https://boards.straightdope.com/t/how-does-stuff-get-into-the-roots-of-a-plant/518940/5 "2009-11-26T08:05:01Z")
Like **Blake** mentioned, a lot of plants (something like 80% IIRC) have mutualistic fungi - [mycorrhiza](http://en.wikipedia.org/wiki/Mycorrhiza) - that play a role in root nutrition. One of the (many) ways they assist is by changing the pH around the roots to increase the solubility of components such as phosphorous and nitrogen. ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [November 26, 2009, 3:51pm UTC](https://boards.straightdope.com/t/how-does-stuff-get-into-the-roots-of-a-plant/518940/6 "2009-11-26T15:51:32Z")
> [@johnpost](#): > > plants produce CO2 as a waste product during respiration. Plants produce O2 during photosynthesis. these gases are expelled through the leaves and some stems. > [@Blake](#): > > 1. Huh? What s the relevance of gas exchange to the question in the OP? Because > [@Inigo\_Montoya](#): > > Do plants poop? so i made a comment on waste products > [@johnpost](#): > > mineral salts are dissolved in water which the roots take in through transport processes. > [@Blake](#): > > That’s really too simplistic to be correct. > > So it’s correct enough for a layman to say that plants “digest” particles of dirt outside of the root in order to free up essential nutrients because an answer does not provide detail, it is a simple answer, it still can be correct. you object to my answer as too simplistic, then you offer that plants digest dirt which is so simplistic that it is a metaphor that you would offer to someone who is getting their first facts about botany. ---
**Author:** ![Add99](https://avatars.discourse-cdn.com/v4/letter/a/977dab/32.png) [@Add99](https://boards.straightdope.com/u/Add99)\ **Post date:** [November 28, 2009, 4:26pm UTC](https://boards.straightdope.com/t/how-does-stuff-get-into-the-roots-of-a-plant/518940/7 "2009-11-28T16:26:55Z")
Am I correct in my simple understanding: Plant takes in CO2, plant breaks bond, takes carbon and forms its entire structure from that, releasing the oxygen as waste and only takes water soluble trace elements from the roots? This based on uh…some guy that weighed the water and dirt and the resulting tree a long time ago. ---
**Author:** ![Bisected8](https://avatars.discourse-cdn.com/v4/letter/b/a4c791/32.png) [@Bisected8](https://boards.straightdope.com/u/Bisected8)\ **Post date:** [November 28, 2009, 6:55pm UTC](https://boards.straightdope.com/t/how-does-stuff-get-into-the-roots-of-a-plant/518940/8 "2009-11-28T18:55:43Z")
> [@Add99](#): > > Am I correct in my simple understanding: > > Plant takes in CO2, plant breaks bond, takes carbon and forms its entire structure from that, releasing the oxygen as waste and only takes water soluble trace elements from the roots? > > This based on uh…some guy that weighed the water and dirt and the resulting tree a long time ago. That’s about half of it. It’s been a while since GCSE biology, but; Plant takes in CO2 and H2O. The process of photosynthesis converts it into glucose (C6H12O6) and oxygen (O2). Some of the later is released as waste. The glucose is either converted into other substances that make up the plant’s mass (like starch or cellulose) by reacting it with the trace elements or it is respirated in the cells for energy. Photosynthesis: 6CO2 + 6H2O --[Light]–\> C6H12O6 + 6O2 Respiration: C6H12O6 + 6O2 —\> 6CO2 + 6H2O ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [November 29, 2009, 9:25am UTC](https://boards.straightdope.com/t/how-does-stuff-get-into-the-roots-of-a-plant/518940/9 "2009-11-29T09:25:52Z")
> [@johnpost](#): > > so i made a comment on waste products Of course “poop” is solid waste matter. What you were describing is gas exchange. It is no more relevant to a question on defecation and elimination of solid waste than is breathing. Now if you actually wanted to address how plants to dispose of solid waste then you would talk about loading up heartwood or moribund leaves with waste materials amongst other methods. > [@](#): > > because an answer does not provide detail, it is a simple answer, it still can be correct. No, it \*can \*still be correct. In the case of your answer it was simplistic and hence _incorrect_. When someone specifically asks “Do plants digest soil to obtain nutrients” an answer of “Plants take in nutrients that are dissolved in soil water” is incorrect. Plants and associated mycorrhizae do indeed digest soil, and nutrients are actively absorbed by pore proteins in addition to those that are dissolve din water. > [@](#): > > you object to my answer as too simplistic, then you offer that plants digest dirt which is so simplistic that it is a metaphor that you would offer to someone who is getting their first facts about botany. Precisely! I gave a long answer with details, and then concluded that the metaphor _chosen by the asker_ is correct enough for a layman. As opposed to giving no details, giving information that is incorrect by virtue of ommitting the relevant details (essentially a half-truth) and then making up a metaphor of my own. See the differences? Digestion is indeed involved in the extraction of nutrients from the soil by plants. Since that was the precise question asked by the OP, your answer that plants absorb nutrients dissolved in water is so misleading as to be incorrect. It is the same as someone asking if they can get burned by exposure to gamma radiation and you answering that people get burned by exposure to high temperatures. Technically perfectly correct, but so irrelevant to the question asked as to become misleading. Someone reading your response is almost certainly going to conclude that plants _only_ absorb dissolved nutrients and don’t utilise digestion in nutrient absorption. Hence the answer is so simplistic as to be incorrect. ---
**Author:** ![jackdavinci](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackdavinci/32/3259_2.png) [@jackdavinci](https://boards.straightdope.com/u/jackdavinci)\ **Post date:** [December 1, 2009, 7:18pm UTC](https://boards.straightdope.com/t/how-does-stuff-get-into-the-roots-of-a-plant/518940/10 "2009-12-01T19:18:39Z")
> [@Blake](#): > > Of course “poop” is solid waste matter. What you were describing is gas exchange. It is no more relevant to a question on defecation and elimination of solid waste than is breathing. They are both methods of waste elimination. I think you know as well as the other poster did that the OP did not literally mean to ask if plants squatted down and let go with a big greasy turd (you even put “poop” in quotes…). > [@Blake](#): > > Someone reading your response is almost certainly going to conclude that plants _only_ absorb dissolved nutrients and don’t utilise digestion in nutrient absorption. Hence the answer is so simplistic as to be incorrect. I thought it was pretty clear what kind of answer he was giving, and what he meant. I certainly didn’t come to that conclusion. And he’s right, your answer was more detailed, but still not complete, so your complaints are somewhat hypocritical. And “utilize digestion” is somewhat misleading. Do the plants themselves secrete digestive enzymes, does the digestion occur internally or externally, etc. Even with the symbiotic soil organisms, the plant could not survive by itself. It has a complex codependent relationship with most of the other fauna and flora in the local and non local environment to varying degrees. It’s better to just specify what the plant itself is doing. I’m feeling very disappointed right now at the inability to sling personal insults at you, but I can’t be bothered to pit you.