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Old 17-09-2003, 09:02 PM
Fred
 
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Default Genetic engineering of plants

You'll have to forgive my lack of technical expertise or knowledge, I'm a
layman but have particular questions to ask about this subject.

From news items and reading New Scientist it appears to me that all the
efforts to produce new cultivars and added properties have so far involved
the transfer of genes from one plant or animal to another in order to imbue
the particular plant with a particular quality.

Have any efforts been made not to do this, but to increase the efficiency of
the photosynthesis operating in the plant? I have read that photosynthesis
is in nature a very inefficient process, possibly less than 2% efficient.
Surely
there's huge potential for improvement in this?
Instead of no-freeze tomatoes or disease-resistant crops we'd have crops
which grow in a quarter the time or yield many times the usual amounts in
the same cultivated acreage and with no additional nitrogen required and no
danger of cross-species gene or resistance transfer.

Thanks
Fred.




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Old 17-09-2003, 09:22 PM
P van Rijckevorsel
 
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Default Genetic engineering of plants

Fred schreef
Have any efforts been made ... to increase the efficiency of
the photosynthesis operating in the plant? I have read that photosynthesis
is in nature a very inefficient process, possibly less than 2% efficient.


Thanks
Fred.


+ + +
A first obstacle is that most improvements in efficiency in human endeavour
are driven by copying something from plants or animals.

For the reverse to work human ingenuity first would have to reach a halfway
point (where it comes up with solutions just as good as those in plants or
animals). This still seems a very long way off.
PvR


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Old 17-09-2003, 10:20 PM
Stewart Robert Hinsley
 
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Default Genetic engineering of plants

In article , Fred
writes
Instead of no-freeze tomatoes or disease-resistant crops we'd have crops
which grow in a quarter the time or yield many times the usual amounts in
the same cultivated acreage and with no additional nitrogen required and no
danger of cross-species gene or resistance transfer.


If a plant grows twice as fast, it'll need twice as much nitrogen.
Several essential classes of biochemicals contain nitrogen, including
proteins and nucleic acids.

There's still the dangers of cross-breeding with wild species. A weed
which outgrows other plants would be a severe danger to the ecosystem.
--
Stewart Robert Hinsley
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Old 17-09-2003, 11:15 PM
P van Rijckevorsel
 
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Default Genetic engineering of plants

Fred writes
Instead of no-freeze tomatoes or disease-resistant crops we'd have crops
which grow in a quarter the time or yield many times the usual amounts in
the same cultivated acreage and with no additional nitrogen required and

no
danger of cross-species gene or resistance transfer.


Stewart Robert Hinsley schreef
If a plant grows twice as fast, it'll need twice as much nitrogen.
Several essential classes of biochemicals contain nitrogen, including
proteins and nucleic acids.


+ + +
One tomato will require a fixed amount of nitrogen, irrespective of the
speed at which it grows. If a plant produces two tomatos where before it
produced only one it will require more nitrogen.
For many plants the limiting factor is water. If photosynthesis is twice as
efficient, likely a plant will grow twice as fast.

The way technology develops it may prove to be easier to adjust the output
of the sun to give more light of the right wavelengths, so as to have plants
growing more quickly? The sun is just a big nuclear fusion reactor: it may
well be more susceptible to fiddling than the process of photosynthesis. (Of
course, if this goes wrong and the sun should explode even a little bit the
present worries on global warming will seem irrelevant)
PvR



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Old 17-09-2003, 11:19 PM
P van Rijckevorsel
 
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Default Genetic engineering of plants

Fred writes
Instead of no-freeze tomatoes or disease-resistant crops we'd have crops
which grow in a quarter the time or yield many times the usual amounts in
the same cultivated acreage and with no additional nitrogen required and

no
danger of cross-species gene or resistance transfer.


Stewart Robert Hinsley schreef
If a plant grows twice as fast, it'll need twice as much nitrogen.
Several essential classes of biochemicals contain nitrogen, including
proteins and nucleic acids.


+ + +
One tomato will require a fixed amount of nitrogen, irrespective of the
speed at which it grows. If a plant produces two tomatos where before it
produced only one it will require more nitrogen.
For many plants the limiting factor is water. If photosynthesis is twice as
efficient, likely a plant will grow twice as fast.

The way technology develops it may prove to be easier to adjust the output
of the sun to give more light of the right wavelengths, so as to have plants
growing more quickly? The sun is just a big nuclear fusion reactor: it may
well be more susceptible to fiddling than the process of photosynthesis. (Of
course, if this goes wrong and the sun should explode even a little bit the
present worries on global warming will seem irrelevant)
PvR





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Old 18-09-2003, 03:12 AM
Frank Martin
 
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Default Genetic engineering of plants

Why not go to the obvious limit and breed the fruits themselves in culture.
One can envisage huge vats full of tomatoes (or whatever) in a nutrient
broth under controlled conditions, with a feedstock of tomato tissue, sugar,
hormones, minerals etc etc. This would eschew photosynthesis and have the
fruits growing in the dark. In fact one could grow tomatoes (or whatever)
on MARS! They do it with penicillin now.

"Fred" wrote in message
...
You'll have to forgive my lack of technical expertise or knowledge, I'm a
layman but have particular questions to ask about this subject.

From news items and reading New Scientist it appears to me that all the
efforts to produce new cultivars and added properties have so far involved
the transfer of genes from one plant or animal to another in order to

imbue
the particular plant with a particular quality.

Have any efforts been made not to do this, but to increase the efficiency

of
the photosynthesis operating in the plant? I have read that photosynthesis
is in nature a very inefficient process, possibly less than 2% efficient.
Surely
there's huge potential for improvement in this?
Instead of no-freeze tomatoes or disease-resistant crops we'd have crops
which grow in a quarter the time or yield many times the usual amounts in
the same cultivated acreage and with no additional nitrogen required and

no
danger of cross-species gene or resistance transfer.

Thanks
Fred.






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Old 18-09-2003, 03:44 AM
Fred
 
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Default Genetic engineering of plants


"P van Rijckevorsel" wrote in message
...
Fred writes
Instead of no-freeze tomatoes or disease-resistant crops we'd have

crops
which grow in a quarter the time or yield many times the usual amounts

in
the same cultivated acreage and with no additional nitrogen required

and
no
danger of cross-species gene or resistance transfer.


Stewart Robert Hinsley schreef
If a plant grows twice as fast, it'll need twice as much nitrogen.
Several essential classes of biochemicals contain nitrogen, including
proteins and nucleic acids.


+ + +
One tomato will require a fixed amount of nitrogen, irrespective of the
speed at which it grows. If a plant produces two tomatos where before it
produced only one it will require more nitrogen.
For many plants the limiting factor is water. If photosynthesis is twice

as
efficient, likely a plant will grow twice as fast.

The way technology develops it may prove to be easier to adjust the output
of the sun to give more light of the right wavelengths, so as to have

plants
growing more quickly? The sun is just a big nuclear fusion reactor: it may
well be more susceptible to fiddling than the process of photosynthesis.

(Of
course, if this goes wrong and the sun should explode even a little bit

the
present worries on global warming will seem irrelevant)
PvR




Thank you for the replies to date to my enquiry.
Next question; are there any aquatic plants (seaweeds) growing in the Dead
Sea, or is the salt concentration too high for them?
Thanks
Fred.


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Old 18-09-2003, 03:12 PM
Beverly Erlebacher
 
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Default Genetic engineering of plants

In article ,
P van Rijckevorsel wrote:
One tomato will require a fixed amount of nitrogen, irrespective of the
speed at which it grows. If a plant produces two tomatos where before it
produced only one it will require more nitrogen.
For many plants the limiting factor is water. If photosynthesis is twice as
efficient, likely a plant will grow twice as fast.


Yeah, and if they have enough water, the limiting factor is often CO2.
It's economically worthwhile to crank up the CO2 level in greenhouses
when growing lettuce and "Dutch aquarium" fanatics add CO2 to the water
to get that incredibly lush growth of aquatic plants.

Only when the plant gets the most it can use in the way of water, mineral
nutrients, light and CO2 is it going to run into the intrinsic limits to
photosynthesis and growth. Using genetic engineering to increase food
production is better directed to develop plants that will grow well under
worse conditions. A few years ago a collaborative project between the
U of Toronto and UC Davis moved some Arabidopsis genes for salt tolerance
into tomatoes. With all the soils in the world that have been degraded
by mineral salts from fertilizer overuse and irrigation, salt tolerance
may be one of the most valuable traits that can be engineered into crops.
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Old 18-09-2003, 03:22 PM
 
Posts: n/a
Default Genetic engineering of plants


On 18-Sep-2003, "Fred" wrote:

You'll have to forgive my lack of technical expertise or knowledge, I'm a
layman but have particular questions to ask about this subject.

From news items and reading New Scientist it appears to me that all the
efforts to produce new cultivars and added properties have so far involved
the transfer of genes from one plant or animal to another in order to
imbue
the particular plant with a particular quality.

Have any efforts been made not to do this, but to increase the efficiency
of
the photosynthesis operating in the plant? I have read that photosynthesis
is in nature a very inefficient process, possibly less than 2% efficient.


The first step in photosynthesis, where light is turned into chemical
energy, is nearly 50% efficient. There is not much scope to increase its
efficiency.

The figure of 2% efficiency is probably arrived at by dividing all the
energy in the sunshine falling on the plant by the amount of energy locked
up in the above-ground parts of the plant. The difference between 50%
efficiency in the primary step and the 2% efficeincy over all is related to
the energy used in growing the plant, including its roots, maintaining it,
and propagating it. A comparable calculation for an electric power station
would have to take into account all the energy used in mining and
transporting the coal, building the power station and maintaining it. The
efficiencies of power stations are usually calculated by dividing the energy
released by the coal by the energy in the electricity produced. These
figures are misleading.

Surely
there's huge potential for improvement in this?
Instead of no-freeze tomatoes or disease-resistant crops we'd have crops
which grow in a quarter the time or yield many times the usual amounts in
the same cultivated acreage and with no additional nitrogen required and
no
danger of cross-species gene or resistance transfer.

Thanks
Fred.

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Old 20-09-2003, 06:02 PM
Martin Hodson
 
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Default Genetic engineering of plants

"With all the soils in the world that have been degraded by mineral
salts from fertilizer overuse and irrigation, salt tolerance may be
one of the most valuable traits that can be engineered into crops."
The theory is great. When I did my doctorate on salt tolerance in the
late 70's/early 80's I bought a book "The Genetic Engineering of
Osmoregulation" (date 1980) all about how to engineer salt tolerance
in plants, and it still resides on my bookshelf. 23 years later we
still have no great advances, and no wonder salt tolerant crop. I
think the reasons are twofold:
1) Salt tolerance involves many genes, all interacting (very complex).
So far the GM crops that have been produced tend to be rather simple
efforts involving the change in one gene (e.g. herbicide resistance).
2) Naturally salt tolerant plants grow VERY slowly, and have low
yields. Probably a lot of the energy which normally goes into growth
is going into making the plant tolerant. So even if we can transfer
the salt tolerance genes to a crop it may well slow the plant down,
and decrease its yield very considerably.
Best Wishes,
Martin Hodson


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Old 20-09-2003, 08:02 PM
P van Rijckevorsel
 
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Default Genetic engineering of plants

Martin Hodson schreef
"With all the soils in the world that have been degraded by mineral
salts from fertilizer overuse and irrigation, salt tolerance may be
one of the most valuable traits that can be engineered into crops."
The theory is great. When I did my doctorate on salt tolerance in the
late 70's/early 80's


+ + +
Just idle curiosity: from time to time I am thinking about going and looking
for good (general) references on Haloxylon. I have the feeling there should
be a considerable amount of literature out there but I don't run into it
easily.

Any suggestions?
PvR




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