Oops, I think sagebrush is actually a C4 plant too. At any rate, it's my understanding that C4 photosynthesis is an advantage in that plants can continue photosynthesizing happily at higher temperatures than C3 plants, but not that they can produce more carbon at any temperature. C4 loses less carbon to photorespiration but takes more energy overall because of it's extra steps. C3 plants must be able to catch up at more moderate temperatures.
--M On Tue, Dec 20, 2011 at 7:53 PM, Wayne Tyson <landr...@cox.net> wrote: > 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 SprintŽ Now Network from my BlackBerryŽ >>> >>> >>> -----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/ <http://droughtadaptation.org/> < >>>> http://www.droughtadaptation.**org/ <http://www.droughtadaptation.org/> >>>> > >>>> >) >>>> through February 1, 2012. >>>> >>>> ----- >>>> No virus found in this message. >>>> Checked by AVG - www.avg.com >>>> Version: 10.0.1415 / Virus Database: 2108/4090 - Release Date: 12/19/11 >>>> >>>> >>>> >>> ----- >>> No virus found in this message. >>> Checked by AVG - www.avg.com >>> Version: 10.0.1415 / Virus Database: 2108/4092 - Release Date: 12/20/11 >>> >>> >>> > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > Version: 10.0.1415 / Virus Database: 2108/4092 - Release Date: 12/20/11 >
