Amartya and Ecolog: I think Amartya understands my question quite well.
Well, yes, it would have to be based upon individuals, but of course in large enough numbers to indicate the amount of differences intra-specifically and "inter-generically." I suspect that fairly large numbers might be needed to make the evidence sufficiently convincing and the research design "salable." While I did not want to make my enquiry excessively convoluted this early in the process (I don't want to bias the answers), I believe that what you say is more or less what I had in mind; in addition, I think your hypothesis (. . . there would be a huge amount of intraspecific variation caused by the specific conditions of water and nutrients an individual may have encountered in its lifetime to date. . . . In addition, there would also be interspecific variation . . . especially when comparing species in arid and moist environments, with a larger water to biomass ratio expected for aridland vegetation as compared to vegetation growing in humid climes.) would make an acceptable point of beginning for research. Of course, I am especially interested in the more dramatic/significant differences, if any, but the intra-specific differences would be interesting. I agree that any such investigation would have to be in a properly controlled laboratory environment (note that my question is based on water UPTAKE, not on water availability), and I hope you or others will investigate further. As I said, I know of no such research that has been done; that doesn't mean there hasn't been, but if there has, I would be interested in the conclusions, commentary, and replicate studies that firm up or refute conclusions. What would pique my curiosity the most would be comparisons between the most radical apparent extremes possible, such as cactus and cattails, but that might or might not pose practical issues in the research design; I just haven't thought that out very well yet. I have other variables in mind, but don't want to complicate the issue with such meanderings at this point. Yes, there would be implications for water use efficiency, but I suspect there might be an elephant in the room on this one. Again, I don't want to bias comments, and certainly not research, so I will button my lip on my speculations. I look forward to your research and further discussion with all those interested. WT ----- Original Message ----- From: "Amartya Saha" <[email protected]> To: <[email protected]> Sent: Thursday, August 20, 2009 9:45 AM Subject: Re: [ECOLOG-L] Ecohydrology Ratio of water to biomass Re: [ECOLOG-L] Postdoc: Ecohydrology/Plant Water Use, Duke University hello Wayne, this is a very interesting question - if i understand you correctly, you are enquiring into how much water an individual of a species has taken up in its lifetime (to date) and connecting this with the total biomass produced to date (including shedded leaves, sloughed off roots, fruits, etc). Now this total biomass over lifetime estimate would be available only in a greenhouse setting. So alternatively you seek to get an estimate of total water uptaken and relate that to dry biomass at an instant of time. I imagine there would be a huge amount of intraspecific variation caused by the specific conditions of water and nutrients an individual may have encountered in its lifetime to date. In addition, there would also be interspecific variation ( as you allude to while comparing cactus and corn), especially when comparing species in arid and moist environments, with a larger water to biomass ratio expected for aridland vegetation as compared to vegetation growing in humid climes. this could be tied in with species level Water Use Efficiency, I guess. cheers amartya Quoting Wayne Tyson <[email protected]>: > Ecolog: > > It depends upon how one defines "water use efficiency," I suppose, but > not in the "production" sense as commonly conceived in the in the case > of agriculture and horticulture, but I wouldn't want to rule those out > either. To put it in contrast, agriculture/horticulture tends to be > more concerned with the amount of production or keeping a plant in a > state of luxury consumption most of the time, whereas "wild" > self-sufficient vegetation is more "concerned" with survival and > reproduction. > > To cite a couple of practical phenomena, consider "cattails" (Typha > sp.) growing at the edge of a body of water, and draw a graph, say, at > the top of the plants to indicate one rough measure of biomass; as > water intake declines, biomass declines (setting aside other > effects--O2, pH, nutrients etc.) for the moment). In a cultivated > field, one can observe similar variations due to water intake. > > I hope this helps; I apologize for not being clearer--please continue > to ask for further clarification as necessary. > > WT > > > ----- Original Message ----- From: "Samuel Pierce (spierce1)" > <[email protected]> > To: "Ecological Society of America: grants, jobs, news" > <[email protected]>; "Wayne Tyson" <[email protected]> > Sent: Thursday, August 20, 2009 5:39 AM > Subject: RE: [ECOLOG-L] Ecohydrology Ratio of water to biomass Re: > [ECOLOG-L] Postdoc: Ecohydrology/Plant Water Use, Duke University > > > Just to clarify, you are asking about water use efficiency? > > ________________________________________ > From: Ecological Society of America: grants, jobs, news > [[email protected]] On Behalf Of Wayne Tyson [[email protected]] > Sent: Wednesday, August 19, 2009 11:01 PM > To: [email protected] > Subject: Re: [ECOLOG-L] Ecohydrology Ratio of water to biomass Re: > [ECOLOG-L] Postdoc: Ecohydrology/Plant Water Use, Duke University > > Ecolog: > > Thanks to Adrian for the reference; however, for clarification, I am looking > for the RATIO of biomass to total water intake, not just water content at > any given moment. That is, the total water intake over the entire lifespan > of the plant compared to the dry biomass. For example, a cactus of a given > age would have a high ratio of total water CONTENT to dry biomass, but its > ratio of the total amount of water required to produce a given unit of dry > biomass might or might not be similar to that of, for example, a corn plant > or a redwood tree. My question is aimed at unearthing research of that > kind--or confirming whether or not such research has been done. I don't know > of any--that's why I'm asking. > > WT > > > ----- Original Message ----- > From: "Adrian Harpold" <[email protected]> > To: <[email protected]> > Sent: Wednesday, August 19, 2009 5:31 PM > Subject: Re: [ECOLOG-L] Ecohydrology Ratio of water to biomass Re: > [ECOLOG-L] Postdoc: Ecohydrology/Plant Water Use, Duke University > > > Wayne, > > Check the World's water by Gleick et al. It has a nice table with > various water contents. > > Adrian > > On Wed, Aug 19, 2009 at 6:19 PM, Wayne Tyson<[email protected]> wrote: >> Ecolog: >> >> I have not kept up to date in this area, but I hope someone will be kind >> enough to help me facilitate the necessary work to rectify that, beginning >> with answers to the following question: >> >> 1. Has anyone studied the ratio of total water intake to biomass exclusive >> of water content? (For example, a cactus and a "corn" plant? I would be >> most >> interested to see graphic comparisons of a diverse and large number of >> species. I am curious about the range of differences and the research >> methodology.) >> >> WT >> >> PS: I have left the message below attached for reference; it stimulated >> the >> question, but there is no direct relationship. >> >> ----- Original Message ----- From: "Will Cook" <[email protected]> >> To: <[email protected]> >> Sent: Wednesday, August 19, 2009 10:09 AM >> Subject: [ECOLOG-L] Postdoc: Ecohydrology/Plant Water Use, Duke University >> >> >> [For more opportunities, please see the ESA Ecophys section website >> http://www.biology.duke.edu/jackson/ecophys/postdoc.htm ] >> >> Postdoctoral Position in Ecohydrology – Plant Water Use >> >> The Biology Department and Nicholas School of the Environment at Duke >> University seek a biological or earth system scientist in ecohydrology >> and plant water transport. The three-year project, funded by the >> National Science Foundation, compares the functioning of deep (5-20 >> meters underground) and shallow roots and stems for trees growing in the >> southern United States. It uses a novel cave system developed by the PIs >> in central Texas to study tree roots in situ and is based on previous >> molecular-based fingerprinting to match the roots to their respective >> shallow counterparts and tree trunks. The research questions include, 1) >> How much water that trees use comes from deep underground? 2) What are >> the unique physical characteristics of deep roots that promote water >> transport? and 3) To what extent do specialized water channels in plants >> contribute to their ability to take up and transport water? Primary >> responsibilities may include installation and maintenance of sapflow and >> microclimate monitoring equipment, periodic collection of plant >> physiological and structural data, lab physiological and hydraulic >> measurements, and/or modeling of water uptake and transport. >> >> Send a CV, statement of interests, and names of three references to: >> [email protected] or Rob Jackson, Professor, Biology Department and >> Nicholas School, Box 90338, French Sciences Building 3311, Duke Univ., >> Durham, NC 27708-0338. Duke is an equal opportunity employer; minority >> applicants are strongly encouraged to apply. Applications will be >> reviewed as they are received; please apply by September 15, 2009 for >> full consideration. Lab web page: http://www.biology.duke.edu/jackson >> >> -- >> Charles W. (Will) Cook w 919-660-5144 >> http://www.duke.edu/~cwcook [email protected] >> Box 90338, Biology Dept., Duke Univ., Durham, NC 27708 >> >> >> -------------------------------------------------------------------------------- >> >> >> >> No virus found in this incoming message. >> Checked by AVG - www.avg.com >> Version: 8.5.409 / Virus Database: 270.13.61/2313 - Release Date: 08/19/09 >> 06:03:00 >> > > > -------------------------------------------------------------------------------- > > > > No virus found in this incoming message. > Checked by AVG - www.avg.com > Version: 8.5.409 / Virus Database: 270.13.61/2313 - Release Date: 08/19/09 > 06:03:00= > > > -------------------------------------------------------------------------------- > > > > No virus found in this incoming message. > Checked by AVG - www.avg.com > Version: 8.5.409 / Virus Database: 270.13.61/2313 - Release Date: > 08/19/09 06:03:00 Department of Biology, University of Miami www.bio.miami.edu/asaha -------------------------------------------------------------------------------- No virus found in this incoming message. 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