Subject: Re: plant waste products

From: [email-masked]
Date: 22 Mar 1996 03:14:14 GMT

In article <[email-masked]>, [email-masked] writes:
>>[email-masked] writes:
>>> yes, this is a serious question.....
>>> 
>>> do plants produce solid waste by-products?  if so, how do they discard 
>>them? 
>>> are all wastes disposed of through trasnpiration?
>>> 
>>> Jesse
>>
>>Wander through a forest. Or for that matter, under any tree.
>>You will be walking on the by-products of plants. Plants
>>produce virtually all of the energy and organic materials used
>>by other organisms. Some is eaten while the plant is alive. But
>>most goes to the decomposers. They do a very nice job of taking
>>care of all of those solid wastes. 
>>-- 
>>Associate Professor (Emeritus)
>>University of Virginia
>>[email-masked]
>
>weellllll.....my question was not "do plants become waste products"....
>or "how do plants fit into the food/energy chain?"...
>let me rephrase the question...
>
>it was, to put it simpler terms....."do plants shit?"
>
>i.e. does a plant
>produce solid-waste by-products (not through discarding of refuse materials 
>such as dead leaves)...for example, in animal biology, some toxins can be 
>passed through the digestive system and discarded through feces or urine,
>other toxins such as mercury/lead are contained within the organism and 
>can reach lethal levels over time.  
>
>as an example, if a plant takes in more iron than it "needs", does the 
>organism discard the extraneous materiali (i.e. take a dump), or does
>the "extra" iron remain within the organism...I can see how gaseous/liquid
>materials can be disposed of....but what about solids?????
>
Stored in vacuoles, although a very few plants, such as some mangroves, can
excrete some unwanted products.  These mangroves excrete salt.
Vacuoles have quite a few other functions too.
The endodermis (an inner layer of the root) can also regulate what gets into
the vascular system.
May I recommend a basic botany text - always to be found in your library?
Stephanie

>Jesse

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From: [email-masked]
Date: Wed, 20 Mar 1996 00:54:48 GMT

i.e. does a plant

Jesse

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From: [email-masked] (Wayne Hughes)
Date: 22 Mar 1996 09:29:28 GMT

>it was, to put it simpler terms....."do plants shit?"

 Animals take dumps because they ingest solids and don't
 extract everything.  Plants don't take in solids at all
 and have nothing to get rid of.  Everything a plant takes
 in comes across a membrane.

 THe original response, that plants drop the parts of themselves
 that are no longer needed, is just right.  Plants grow
 differently from animals, i.e., indeterminately as opposed
 to determinately; why should they excrete the same?

 Wayne

-- 
Wayne Hughes  |              Keep your carbon dioxide fixed!!
Botany Dept   |            http://morgan.botany.uga.edu/wayne.htm
Univ Georgia  | Keywords: botany, Arabidopsis, gay stuff, astronomy, ponds,  
Athens,GA USA | bonsai, cats, dormancy, rural, seeds, juggling, books, movies.

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From: [email-masked] (Wayne Hughes)
Date: 22 Mar 1996 10:31:58 GMT

> in comes across a membrane.

 OK, I'm taking the egregious step of followup up to my own post,
 but if you look more closely you see that the fundamental process
 of getting nutrients is essentially the same for plant and animal
 with two major differences.  Both require bringing in desirable
 nutrients through absorptive surfaces across a membrane.  In plants,
 the absorptive surfaces are sent as root hairs into a food mass.
 In animals, the food mass is brought inside the animal to be
 digested and absorbed.  Of course, the food masses are different
 in composition - animals need the complex organics; plants only
 need inorganic nutrients (excepting oxygen and carbon dioxide taken
 in passively).

 So animals have a residual food mass inside the body which has to
 be gotten rid of.  That residue always stays outside the plant
 root hairs and doesn't have to be gotten rid of.

 Now there are plants which take in substances that have to be 
 gotten rid of - salt marsh grasses for example.  Excess salt
 is secreted through specialized glands, but this isn't exactly
 parallel to excretion in animals, nor to sweating which also
 takes place through glands but for different reasons (cooling).

 Wayne

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From: [email-masked] (B.K.)
Date: Sun, 24 Mar 1996 19:43:35 GMT

>>> are all wastes disposed of through trasnpiration?
Try looking up leaf exudates in a plant physiology text.  Exudates are
common to grasses and are often confused with dew.  Sorry, turfgrass
is my specialty so I can't comment on dicots.  They contain: mineral
salts, sugars, amino acids, and other organic compounds.  Exudates
form at the leaf ends, while dew forms over the entire leaf.  Exudates
can be a real problem in turf as it promotes fungus growth.

Form by "guttation from the hydrathodes at the ends of uncut leaves or
may be the result of direct wound exudation from freshly cut turfgrass
leaves.".  Beard. J.B., Turfgrass Science and Culture. pp. 302

Good Luck,
B.K.

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From: [email-masked]
Date: Thu, 28 Mar 1996 21:07:51 GMT

>May I recommend a basic botany text - always to be found in your library?

been there, done that Stephanie....(as well as purchasing several 
"basic" botany and not so "basic" botany books :-) ) didn't find the 
information I was looking for so I asked here..course..could be this feeble 
minded engineering brain of mine can't comprehend the text ;-)...closest 
answer that I've found to what I'm looking for seems to be that excess 
minerals (considered for this discussion to be "solid-waste") can be carried 
out of the plant through transpiration...as well as through the excretions 
some plants are capable of...as you pointed out.   To those who are 
listening...no I'm not crazy and running around looking for plant-poops (ROFL) 
..

now for another "basic" botany question (insert digging through books 
here..owww! paper cut, hate it when that happens...) ...

how does a plant regulate the even distribution of minerals throughout its 
system?  or does it?

TIA,

Jesse  ... basic botany (-101)

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From: [email-masked]
Date: Fri, 29 Mar 1996 23:13:24 GMT

In article <[email-masked]>,
> to determinately; why should they excrete the same?

hmmm, so you're saying minerals such as iron, magnesium, sulfur are not 
solids? I didn't think that they were liquid (though they may certainly be 
held in suspension)...and last I heard they weren't gaseous...so  please tell 
me what they are?? and if you get big chunks of minerals together and you can 
do things such as ....build bridges, planes, cars etc..oh my...get 'em in 
small enough chunks and they can be taken into plants

sorry for the sarcasm (it really is quite out of character for me, well 
most of the time anyway ;=) )...but I didn't have my coffee this morning....

by the way, though no one responded as such, some carniverous plants do take 
large solids within their "body" <note the quotes here> for digestive 
purposes...usually a modified appendage which after one or more uses (pitcher 
plants, venus fly traps etc) is discarded..yes I know about drawing in 
the "goodies" from the plant meal (hey I watch David Attenborough 
<grin>)..this is not the type of solid waste I'm speaking of.....

stephanie (as well as several others) has been kind enough to provide me with 
a description that I think fits what I'm looking for...I'm including it here 
(she sent it via private email and I'm including it without her 
permission..sorry stephanie :-) )..though several people responded in kind, 
her description I feel was the most descriptive...

>plants cannot transpire anything except water.

this one I'm still looking into.....I "think" that minerals can indeed be held 
in suspension during transpiration....

>There are secretory structures such as those in flowers that produce nectar,
>and similar structures are found on the photosynthetic stems of some flowers 
>probably to attract ants.  These do include some minerals, but I believe
>intentionally.
>Waste products are stored in vacuoles.
>I use Raven, Evert and Eichhorn when I teach intro bot - their chapter 2 has 
a
>section on parts of a plant cell. The vacuoles appear to have antibiotic
>products but also have been known, for years, to store waste (e.g. vitamin c 
>is a plant waste product).  Excess minerals are usually kept out of the 
vascular
>cylinder by the endodermis, the innermost layer of the cortex.  <editorial 
snip here :-) > Some plants can accumulate heavy metals
>without harm and can be (and are being, to some extent) used to clean up 
>mining areas.  If you want to look further into this, then I would suggest 
>plant physiology and biochem books.  
>All living cells have a vacuole, and, in a mature cell, this may occupy 90% 
of
>the cell's internal volume.  Since the membrane is able to actively control
>transport, the stored wastes do not harm the nucleus, etc.
>Stephanie

thankyou for the response stephanie, yours and other responses have given me 
some new insights for looking into additional information.....which is a big 
help

the reason I'm curious about this subject, came about from orchids...I grow 
orchids as a hobby (though my better half would claim its an obsession rather 
than a hobby, they're kinda like Lays potato chips)...

now I know that orchids are known to want very little in the way of 
fertilizer.....(but "knowing" something has never stopped me from trying for 
myself :-) )....I've done some experimenting with varying the amounts of 
fertilizer (same strength fertilizer, in this case 7-7-7 (a well known major 
brand...can provide the "guarateed" composition), applied 8x strength in same 
quantities of water, plants are all clones in same growing conditions, across 
several species such as vanda, oncidium and luisia, etc, 10 plants of each 
were normal , over, under-fertilized ) applied over long periods (12-18 
months).  What I have noticed is that the plants receiving higher levels of 
fertilizer actually decline...at first there is some additional vegetative 
growth an immediate decrease or total lack of flowering (compared to the 
"control plants") even malformed blooms...then depending on species (but 
without fail) a sudden decline in overall plant health...lack of growth, die 
back, then root decline...control plants look good, nice growth rate, good 
bloom results....no abnormal disease or pests were noted.....sooooo where that 
leads me is that I'm trying to figure out is not so much what caused it (even 
though not perfect lab conditions I think its safe for me to think OVER 
FERTILIZATION) but why???? 

were the plants damaged by a buildup of minerals in the plant (hence the 
question solid waste byproducts), if so - why can't a plant divest itself of 
the builtup minerals? or did the plants just "burn themselves out?"
and if so, why were some parts of the same plant (sympodial habit) effected 
more quickly than other parts? was the plant decline due to unviewable root 
damage which took time to show up?  questions, questions, questions....

not the most groundbreaking questions I'm sure....but I'm curious....

thanks again to those who answered.......constructively.....and I'm still very 
open to input...constructive or otherwise...

back to puttering in the greenhouse....

Jesse

p.s. the orchids to which a lower amount of fertilizer (1/8 dosage) were 
applied, responded as if a "recommended" dose of fertilizer had been applied

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From: [email-masked] (Bob Vickery)
Date: Mon, 01 Apr 1996 01:14:41 +1100

In article <[email-masked]>,
[email-masked] wrote:
snip
>how does a plant regulate the even distribution of minerals throughout its 
snip
Plants have a partial control of the distribution of minerals but the
details of the mechanisms are obscure (to me). Some, like calcium and boron
go with the transpiration stream and thats it.  Others, like potassium,
phosphate, sodium are actively controlled.  The control systems involve
coutercurrent flows in xylem and phloem and transfer cells that carry
minerals between the two streams.  Active accumulation into into internal
sinks (vacuoles) and external sinks (glands) are important.  Sometimes the
controls aren't that good as when plants accumulate toxic amounts of
phosphate (toxic to plants that is).