All the leaves on the plant "feed" the whole plant and so all the fruit on the plant. Just as all the roots feed the whole plant.

Dave

This post was edited by digdirt on Thu, Aug 8, 13 at 18:44

I like what Dave said.
Leaves , I think, do not feed, the roots do.

Thanks for the replies, assuming they are correct.
I was wondering the same think as I removed some leaves near a tomoto truss and wondered if I was starving the plant.

The leaves supply the energy which is converted to carbohydrates and fed into the the tomato, where they are converted into sugar when ripening.

The roots supply the water and other trace elements ie Nitrogen Potassium and Plutonium ;)

Well not so much Plutonium I guess more Phosphorous which is the other element on in a NPK fertiliser.

There are of course other trace elements ie Calcium Iron and other bits and bobs

Actually the roots do supply radioactive Polonium to plants (and make tobacco plants in particular radio active!!) when they are gown if none organic fertilisers, ie some phosphate fertilisers in particular.

Thanks Dave. That is a good explanation for me.

I was considering one leggy plant of mine that I had just plopped into a container with some other plants due to lack of space. It's lost many of it's leaves to various fungal causes but has 3 growing tomatoes on it. One is on a long naked stem with barely any leaves at all, just a little top growth. The others are on stems that fared better in terms of retaining some foliage, so I was just curious whether a tomato's location would make a difference in terms of its outcome. From what you said, I gather the answer is no. They should all turn out approximately the same based on the nutrient and health status of the plant as a whole.

Seysonn, wouldn't it be the case that both roots and leaves feed the plant? Roots by taking up nutrients from the soil and leaves through photosynthesis?

Ah... Esbo snuck in there while I was still writing and settled that last question.

Seysonn, wouldn't it be the case that both roots and leaves feed the plant? Roots by taking up nutrients from the soil and leaves through photosynthesis?

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RIGHT
I thing that plants anatomy/organization is complex and elaborate. In a way we may liken it to us , humans; They have vasculatory system that circulates water + nutrients dissolved in water(like blood), Then get sugar and other stuff made in the leaves and distributes to all plant part. How the leaves operate on the photosynthesis principles,breaths, absorbs solar energy, manufactures sugar ..is complex.

The roots, in addition to being absorber, works as pump, much like human heart., It also has storage tanks. Like in some trees, most of the food is stored in the roots over the winter and pumped back up in the spring.

Leaves are like breathing organs, human nose and lung and also are like solar panels. As breathing organ they absorb oxygen, produce sugar, release carbon dioxide. Then this sugar is transported to the vasculatory system to be used by other parts of plant(flowers, fruits..)

So the leaves play a vital role in plant life. True that it uses some of the nutrients and water (resources) but in return it makes a vital contribution. I would think that any new growth(including leaves) are burdensome on the plants(in short term) until they become established and become a role player. Then there is a delicate optimal balance about the roots and foliage size. Some plants have A VERY long term plans about growth. That is why given the opportunity they will work on expanding their roots and foliage and postponing any flower/fruit production.
So then we, the humans, gardeners, sometimes can interfere in that process and direct the plant growth and goal to optimize our returns. We make Bonsai, dwarfs, determinants, prune the plant ..etc.

A certain amount of 'ordinary' potassium is radioactive... which is why they are always comparing radiation dose to eating a banana.

Also, cesium 134 and 137 are taken up by plants (and humans!) and utilized like potassium. So after nuclear accidents like Fuku, some plants go through massive growth surges due to available nutrients...and then there are the mutations.

Tomatoes are relatively high potassium, so are candidates for Simpson episodes should they grow in fallout zone. And there is still of cesium 137 spread around the US from the nuclear weapons testing half a century ago. So, it is in our food, like it or not.

Tomatoes are relatively high potassium, so are candidates for Simpson episodes

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But potassium is good to reduce blood pressure ... hehe

"One is on a long naked stem with barely any leaves at all, just a little top growth."

I think the main difference you may see in the three tomatoes will be sun damage on the ones that don't have at least partial shade on them.

Betsy

Transpiration, respiration and photosythesis. Google these and you will understand the big picture.

I've decided I want to read further on the topic of how tomato nutrients move through the plant and the specific contributions of roots, leaves and fruit (i.e. I don't even know if fruit makes use of the sun at all).

But - I can't come up with a good google query to find the info I'm looking for (just keep getting the basic NPK info).

Anyone have a suggestion or a good online article to read?

PS thank you all for your contributions so far.

Once again, someone snuck in and answered my question before I finished writing.

And thanks Seysonn for your interesting comments.

Start with this link and (and the many similar sites) then move on to the specifics.

Dave

Here is a link that might be useful: Anatomy of Plants

Thanks Dave. Will do.

-ff

The broad topic you are researching is plant physiology.

Jim

Here is a link that might be useful: Plant Physiology

Posted by seysonn "So the leaves play a vital role in plant life. True that it uses some of the nutrients and water (resources) but in return it makes a vital contribution. I would think that any new growth(including leaves) are burdensome on the plants(in short term) until they become established and become a role player."

I would tend to disagree with this to certain extent.
It depends, if nutrients are limited then green growth might be considered a burden to some extend, but remember as the green grows so does the root network, and assuming you are fertilising it or the soil is already fertile (as most none intensive farmed soils are) I do not see green growth as a burden, I see it as a supplier of energy,
I see it as an extra solar panel on the roof and thus a good think. I don't know if there is an analogy to the nutrient part, maybe if someone had to go and clean the panels once in a while it might be more of a burden on him and so they got dirty and stopped working as well. But even they they are not a burden they just produce less energy than they could have.

Anyhow I have decided to not remove anymore green, I might remove fruits which have no chance of ripening though.

I will see what happens.

Also another point is, if you remove green the plant will just try and grow more!!!!!!!!!!

So that is a burden anyway and it does not have the leaves to power it.

But I shall see in a months time how well my idea works when the fruit should I hope be ripening!!!

I would tend to disagree with this to certain extent.
It depends, if nutrients are limited then green growth
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@ esbo,
The following is JMO>
I am sure nutrients are NOT UNLIMITED. The plant has a limitation in production and delivery of the nutrients. Definitely leaves contribute to that and then take away some.

It is like you hire some people to do an assembly (of something). You have to pay those people and then in return they make a contribution to the productivity, MORE than you pay them. As you keep hiring more an more people, at some point their contribution to productivity will be less than what you pay them. So actually there is some net loss.

That is no wonder that they control growth by prunung in fruit trees, grape vines, flowerin shrubs , like roses, ..on and on.

S...I love the way you use analogies...they seem to make a lot of sense to my brain! haha

@ seysonn yes some nutrients are not unlimited, it is probably fair to say your local garden centre could supply you with far more nutrients than you would ever need or afford.

It depends to an extend on where the plant is growing, if it is in a pot or grow bag there is limit to what nutrients are in the bag, however as most gardeners have a bottled of tomato feed and I have two ;O) there is no real limit.

Another point is plants are far more intelligence than we think, we tend to think of vegetables as lacking brains when the fact is they are more intelligent, certainly in plant growth terms then any gardener, that would put it down to experience.

Plants are not stupid they do not grow a whole load of leaves and then think "oh dear I will never be able to supply all that lot with nutrients!!"

We all know this, we have first hand evidence, if you stick a plant in a small pot it will not grow to the size of a house. Yes small plants can still produce fruit.

I look at it this way, after billion of years of evolution, ie trial and error. that plant has much better idea of how much green stuff it needs on it!!

Seyonns analogy is of course incorrect, it is called the economies of scale, the more workers you hire the more efficient becomes because your overheads are pretty ,much the came, one personally department, one payroll dept etc. one legal dept.

This is one of the reasons why companies merger, so reduce costs my sharing the overheads.

Forming a price rigging monopoly is anther advantage!!!!

Of course there may be other factors to consider, the plant may consider it self under attack as it thinks "why does some idiot keep coming out and chopping bits off me? I better get fruiting before he kills me altogether"

Anyway to get back on topic I think the OP's question is analogous to "which part of the lung supplies oxygen to the arms?"

Of course the lungs are not specific they supply the whole body. If not damage to one part of the lung might cause lose of use of arm or leg.

jimster is right Plant Physiology will answer your question. From a common sense gardening perspective, after a lot of experimenting ( 25yrs) , If you trim non fruit producing branches from a tomato plant you will get bigger fruit . Trim to much and you'll get some sun burning and splitting ! .

This is the 1st year I have tried pruning non fruit producing branches and have had great success in spite of the fact that this has been a terrible year for growing tomatoes in my area. For example my German Johnson heirloom is yielding large fruit ( 1lb +). I put this plant in ground on May 2nd. It is now loaded with large size fruit that I will be able to harvest before the 1st predicted frost date of Sept 22nd.