I think C4 and CAM (Crassulean Acid Metabolism) are different, but I would
rope CAM plants into my question anyway. While they are quite drought
tolerant, I do not know if they actually produce more or less dry biomass or
energy per unit/water than C4 plants or even C3 plants. While one would
think that because C4 plant fix three times the carbon than C3 plants that
biomass/energy production might be three times greater, but I am not
competent to answer that question, hence my post.
I have a HUNCH that there isn't all that much difference in the production
potential per unit/water by the three forms, I have no evidence one way or
the other. Hence my post.
However, since C4 plants fix three times as much carbon, it would seem that
their role in carbon sequestration might be more important than cultivating
them for fuel. On the other hand, since context is everything, it might be
more useful to concentrate on equatorial vegetation as a carbon sink, since
longer-lived C3 dicots like rainforest trees could hold more. It's kinda
like the old proverb that says that one takes money to the bank, one doesn't
take percentages to the bank.
So it seems important to know what all the RELEVANT elements of ecosystems
are and what principles drive research before going off on wild goose chases
(if you will pardon the metaphor).
WT
----- Original Message -----
From: "Martin Meiss" <mme...@gmail.com>
To: <ECOLOG-L@LISTSERV.UMD.EDU>
Sent: Tuesday, December 20, 2011 3:26 PM
Subject: Re: [ECOLOG-L] Plant Physiology Drought tolerance Re: [ECOLOG-L]
course and symposium on plant breeding for drought tolerance
C4 metabolism (also known as Crassulacean acid metabolism) is accomplished
by special biochemical pathways which have their basis in genetics. Since
these pathways evolved in some plants, it seems theoretically plausible,
however difficult, that various manipulations could cause them to appear in
species where they are not currently found. As for the potential yield
increase, once could model that in terms of things like diffusion rates of
CO2 and water, stomatal resistance, temperature, humidity, chemical
efficiency, etc.
Additionally, plants lose water through their cuticle. It seems reasonable
to believe that genetic factors controlling the production of cuticle could
have an impact on drought resistance: thicker cuticle -> less water loss ->
greater drought tolerance (i.e., less wilting, longer survival time between
rains, etc.)
Is this any less plausible than other manipulations that have been carried
out in the past that have resulted in increased yields?
Martin M. Meiss
2011/12/20 Wayne Tyson <landr...@cox.net>
Yes, the issue of wetland plants is an interesting one, if not directly
relevant to drought tolerance and productive potential. However, it does
raise an interesting point about plants living under "luxury" conditions,
their productive potential, and their evolution. This leads to the larger
issue of the relationship of organisms to the elements of their
environments that promote production and limit it. Thank you for raising
it.
My immediate question, however, concerns whether or not selection and
genetic engineering have significant potential, either on a theoretical
basis (What are the foundations for the theory?) or empirical evidence
(which supports or refutes theory), to produce more biomass or crop on
less
water (drought tolerance). That is, what ACTUALLY IS the evidence or
theoretical foundation for such a presumption or conclusion? Further, what
are the limits of the phenomenon, and how much increase in production is
theoretically feasible; also, if such an increase has been demonstrated,
how much increase has been achieved.
If it turns out that there are any flaws in the reasoning that such
increase is possible, now would seem to be the time to, if you will excuse
the expression, arrest further development down some yellow brick road.
WT
----- Original Message ----- From: <as...@bio.miami.edu>
To: "Wayne Tyson" <landr...@cox.net>; <ECOLOG-L@LISTSERV.UMD.EDU>
Sent: Tuesday, December 20, 2011 9:01 AM
Subject: Re: [ECOLOG-L] Plant Physiology Drought tolerance Re: [ECOLOG-L]
course and symposium on plant breeding for drought tolerance
Hi Wayne, an example icould be foodcrops such as rice that today have
hundreds of varieties bred into cultivars over millenia. Plants that grew
in drier regions are known (in agriculture) as being drought tolerant,
relative to rice plants that have ocurred in wetter areas.
Now not being an agricultural scientist, I have nothing to add about
modern day genetic practices like inserting dryland rice genes to achieve
drought tolerance in a 'super' plant.
Cheers, amartya
Sent on the Sprint® Now Network from my BlackBerry®
-----Original Message-----
From: Wayne Tyson <landr...@cox.net>
Sender: "Ecological Society of America: grants, jobs, news" <
ECOLOG-L@LISTSERV.UMD.EDU>
Date: Mon, 19 Dec 2011 14:21:17
To: <ECOLOG-L@LISTSERV.UMD.EDU>
Reply-To: Wayne Tyson <landr...@cox.net>
Subject: [ECOLOG-L] Plant Physiology Drought tolerance Re: [ECOLOG-L]
course and symposium on plant breeding for drought tolerance
Ecolog:
What IS drought tolerance?
What evidence is there that plants can manufacture more biomass/crop
yield
on less water rather than to evade water deficits by continuing to
survive
by reducing biomass production?
WT
----- Original Message ----- From: "David Inouye" <ino...@umd.edu>
To: <ECOLOG-L@LISTSERV.UMD.EDU>
Sent: Monday, December 19, 2011 1:49 PM
Subject: [ECOLOG-L] course and symposium on plant breeding for drought
tolerance
PLANT BREEDING FOR DROUGHT TOLERANCE
Moisture deficits loom as one of the greatest challenges to future crop
production, both in rainfed and irrigated agriculture. Enhancing the
genetic tolerance of crops to drought stress, is considered an essential
strategy for addressing these deficits. To respond to the need for more
plant scientists trained in developing drought tolerant cultivars,
Colorado State University will offer a short course in Plant Breeding
for
Drought Tolerance June 11-22, 2012.
The course will end with a two-day symposium on Plant Breeding for
Drought
Tolerance, which will be given June 21-22, 2012 and is open to the
public.
Confirmed speakers include Drs. John Boyer, John Passioura, Eduardo
Blumwald, Tom Juenger, Amelia Henry, Sean Cutler and Jill Deikman.
TARGET AUDIENCE
The course is targeted to graduate students in the plant sciences, as
well
as to professionals in the public and private sectors. It will provide
three transferable graduate-level credits.
CONTENT
The course will consist of classroom lectures, hands-on lab exercises,
and
field research activities appropriate for a drought breeding and
genetics
program. Course activities are designed around three modules: 1) Whole
Plant Physiology of Drought Stress, 2) Plant Breeding for Drought Stress
Tolerance and 3) Genomic Approaches to Drought Stress Tolerance.
PREREQUISITES
The course will be given in English.
Participants should have a solid understanding of basic plant physiology
and genetics. Prior to the short course, students will review online
material on these topics to provide a common background in breeding and
physiology concepts.
PROGRAM COSTS
The cost of student tuition and fees is $1,800. Accommodations for room
and board are available on-campus for either $850 (double occupancy) or
$1,150 (single occupancy). This cost includes three meals daily. Guests
are also welcome to make their own arrangements for room and board. All
foreign visas and travel arrangements are at students' initiative and
expense.
FUNDING
Partial funding to develop the course was provided by a grant from
USDA-NIFA. No scholarships are available for the course.
REGISTRATION AND INFORMATION
Participants may apply online
(http://www.droughtadaptation.**org <http://www.droughtadaptation.org><
http://www.**droughtadaptation.org/ <http://www.droughtadaptation.org/>
>)
through February 1, 2012.
-----
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