Re: [ECOLOG-L] Plant Physiology Drought tolerance Re: [ECOLOG-L] course and symposium on plant breeding for drought tolerance
Cactus grow slowly when grown under drought conditions. For clarity, please keep in mind what constitutes drought conditions for a Sonoran Desert cactus would be water heaven for many Mojave Desert cactus species. Based on personal experience gained from 30+ years of gardening in the Mojave Desert... Cactus are water efficient when their growing environment demands water efficiency. When grown under more water-luxuriant conditions, all the cactus species with which I am familiar respond with faster growth and attain greater size compared to cactus grown under native conditions. The plants often become water junkies. The excess growth tends to overwhelm the internal support systems of branching cactus such as Cylindropuntia and the plant falls over. Reducing water availability back to a level comparable with native growing conditions tends to severely shock the cactus plant and necrosis to part or all of the plant has been the usual result. From: Merran pantscr...@gmail.com To: ECOLOG-L@LISTSERV.UMD.EDU Sent: Tuesday, December 20, 2011 8:16 PM Subject: Re: [ECOLOG-L] Plant Physiology Drought tolerance Re: [ECOLOG-L] course and symposium on plant breeding for drought tolerance Isn't drought tolerance defined by a plant's water use efficiency? C4 plants have the ability to fix 2 or 3 times more carbon with the same amount of water not because they use less water in photosynthesis, but because they limit photorespiration and the amount of water lost through their stomatas. So they do fix more more carbon with less water, but unless the climatic conditions are perfect I don't think the advantage is really that great. I'm fairly sure that the tropics have a greater abundance of C4 plants than the American deserts, and saltbushes (C4, right?) are not usually that much larger than sagebrushes.. There must be other limiting factors. It's my understanding as well that CAM photosynthesis is not the same as C4 photosynthesis -- I've read that it is a different, even more efficient process. It occurs in desert succulents and allows the plants to open their stomatas only at night, thus losing far less water to transpiration. The CO2 is stored as an acid and metabolised the next day. These plants can breath in up to 40 times more Carbon dioxide than C3 plants with the same water loss. However efficient these plants are, they are also very slow-growing -- something that I have never fully understood. I think that there's a low limit to their acid-storing capabilities. So they lose less water in exchange for performing less photosynthesis each day, but are still creating the same biomass with less water? A saguaro is bigger than a sagebrush, but it took longer for it to get that way? I'm guessing that this will not be the technique they are teaching at the CSU symposium. If I've got any of this wrong, some one please let me know. Surely there must be ways to raise a plant's water use efficiency aside from changing the photosynthetic process. I mean, I just spent my morning picking out which variety of Buffalo Grass to replant my Kentucky Bluegrass lawn with. How about making the plant hairier? Give it a smaller leaf size and orient the leaves directly upwards. Make the leaves waxy with stomatas that don't open fully. Give it stem pleats (such as in cacti) that create shade. But it's my understanding that many of these adaptations also limit CO2 intake and therefore biomass production. I don't know if these adaptations will actually let you breathe in more CO2 for the amount of water lost in transpiration. Anyone? Maybe I'm completely off base but it seems confusing to me to suggest that selection hasn't allowed plants to create the same biomass with less water. Thank you for this conversation -- writing this email really made me think. Merran
Re: [ECOLOG-L] Plant Physiology Drought tolerance Re: [ECOLOG-L] course and symposium on plant breeding for drought tolerance
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
Re: [ECOLOG-L] Plant Physiology Drought tolerance Re: [ECOLOG-L] course and symposium on plant breeding for drought tolerance
Frankly, I don't think it makes much difference either, but I don't claim to be able to explain it. I just have my doubts about assumptions that drought-tolerant plants (including C4's and CAM's) are able to produce more biomass with less water than non-drought-tolerant plants (say, C3's). I'm asking, not telling. But I think it's a fair question. I SUSPECT that drought-tolerance or drought-evasion involves physiological processes that limit growth, and that if one added up the water and the biomass there would be a pretty close correspondence across species and even metabolic strategies; that is, that the differences in productivity are not likely to be impressively great, or greatly significant. That's the reason for the question; I want all y'all who are smarter or who have studied this matter more extensively or intelligently than I to correct my suspicions with solid evidence. Hence my post. WT - Original Message - From: Merran pantscr...@gmail.com To: ECOLOG-L@LISTSERV.UMD.EDU Sent: Tuesday, December 20, 2011 8:16 PM Subject: Re: [ECOLOG-L] Plant Physiology Drought tolerance Re: [ECOLOG-L] course and symposium on plant breeding for drought tolerance Isn't drought tolerance defined by a plant's water use efficiency? C4 plants have the ability to fix 2 or 3 times more carbon with the same amount of water not because they use less water in photosynthesis, but because they limit photorespiration and the amount of water lost through their stomatas. So they do fix more more carbon with less water, but unless the climatic conditions are perfect I don't think the advantage is really that great. I'm fairly sure that the tropics have a greater abundance of C4 plants than the American deserts, and saltbushes (C4, right?) are not usually that much larger than sagebrushes.. There must be other limiting factors. It's my understanding as well that CAM photosynthesis is not the same as C4 photosynthesis -- I've read that it is a different, even more efficient process. It occurs in desert succulents and allows the plants to open their stomatas only at night, thus losing far less water to transpiration. The CO2 is stored as an acid and metabolised the next day. These plants can breath in up to 40 times more Carbon dioxide than C3 plants with the same water loss. However efficient these plants are, they are also very slow-growing -- something that I have never fully understood. I think that there's a low limit to their acid-storing capabilities. So they lose less water in exchange for performing less photosynthesis each day, but are still creating the same biomass with less water? A saguaro is bigger than a sagebrush, but it took longer for it to get that way? I'm guessing that this will not be the technique they are teaching at the CSU symposium. If I've got any of this wrong, some one please let me know. Surely there must be ways to raise a plant's water use efficiency aside from changing the photosynthetic process. I mean, I just spent my morning picking out which variety of Buffalo Grass to replant my Kentucky Bluegrass lawn with. How about making the plant hairier? Give it a smaller leaf size and orient the leaves directly upwards. Make the leaves waxy with stomatas that don't open fully. Give it stem pleats (such as in cacti) that create shade. But it's my understanding that many of these adaptations also limit CO2 intake and therefore biomass production. I don't know if these adaptations will actually let you breathe in more CO2 for the amount of water lost in transpiration. Anyone? Maybe I'm completely off base but it seems confusing to me to suggest that selection hasn't allowed plants to create the same biomass with less water. Thank you for this conversation -- writing this email really made me think. Merran - 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
Re: [ECOLOG-L] Plant Physiology Drought tolerance Re: [ECOLOG-L] course and symposium on plant breeding for drought tolerance
Ecolog: Additional responses to Merran: I very much appreciate Merran's thoughtful response. I have made similar observations, but I do not know of any studies which have settled this matter. I remain open to enlightenment. I will attempt to do justice to Merran's contributions, but am doubtful that I can accomplish that in one or two emails. I hope that Merran and others, particularly some apparently highly qualified individuals who have contacted me off list with some very provocative ideas. In terms of the evolution of C4 plants from C3's and the abundance of the former in the tropics, I see further fertile fields for research. This may open a whole additional can of worms, but might it be that C4 evolved via a mutation that ALSO worked in more mesic circumstances rather than arising only in xeric environments? But this is too much and too distracting for now, and perhaps worthy of a spin-off thread? Later. A saguaro is bigger than a sagebrush, but it took longer for it to get that way? --Merran Exactly! And with respect to KY bluegrass and buffalo grass, I presume that productive potential (quantity) is not as important as persistence under stress. But are not lawns under continuous luxury-consumption (quantity) conditions by definition? I presume that Merran will stress his buffalo grass, and not have to mow down the excess biomass as much (quality, in Merran's eyes, not quantity, which is irrelevant in that context. And context is everything, eh? Let us not neglect RATE calculations, especially if we're going to get picky (nothing wrong with that)? I forgot to mention unit/time, and thanks to Merran for correcting my oversight. I hope someone will clear up the confusion about how selection hasn't allowed plants to create the same biomass with less water as Merran also points out. Any if it has, which plants they are and how much more efficient they are in producing more units of biomass IN LESS TIME OR THE SAME TIME as less efficient non-drought-tolerant plants. WT - Original Message - From: Merran pantscr...@gmail.com To: ECOLOG-L@LISTSERV.UMD.EDU Sent: Tuesday, December 20, 2011 8:16 PM Subject: Re: [ECOLOG-L] Plant Physiology Drought tolerance Re: [ECOLOG-L] course and symposium on plant breeding for drought tolerance Isn't drought tolerance defined by a plant's water use efficiency? C4 plants have the ability to fix 2 or 3 times more carbon with the same amount of water not because they use less water in photosynthesis, but because they limit photorespiration and the amount of water lost through their stomatas. So they do fix more more carbon with less water, but unless the climatic conditions are perfect I don't think the advantage is really that great. I'm fairly sure that the tropics have a greater abundance of C4 plants than the American deserts, and saltbushes (C4, right?) are not usually that much larger than sagebrushes.. There must be other limiting factors. It's my understanding as well that CAM photosynthesis is not the same as C4 photosynthesis -- I've read that it is a different, even more efficient process. It occurs in desert succulents and allows the plants to open their stomatas only at night, thus losing far less water to transpiration. The CO2 is stored as an acid and metabolised the next day. These plants can breath in up to 40 times more Carbon dioxide than C3 plants with the same water loss. However efficient these plants are, they are also very slow-growing -- something that I have never fully understood. I think that there's a low limit to their acid-storing capabilities. So they lose less water in exchange for performing less photosynthesis each day, but are still creating the same biomass with less water? A saguaro is bigger than a sagebrush, but it took longer for it to get that way? I'm guessing that this will not be the technique they are teaching at the CSU symposium. If I've got any of this wrong, some one please let me know. Surely there must be ways to raise a plant's water use efficiency aside from changing the photosynthetic process. I mean, I just spent my morning picking out which variety of Buffalo Grass to replant my Kentucky Bluegrass lawn with. How about making the plant hairier? Give it a smaller leaf size and orient the leaves directly upwards. Make the leaves waxy with stomatas that don't open fully. Give it stem pleats (such as in cacti) that create shade. But it's my understanding that many of these adaptations also limit CO2 intake and therefore biomass production. I don't know if these adaptations will actually let you breathe in more CO2 for the amount of water lost in transpiration. Anyone? Maybe I'm completely off base but it seems confusing to me to suggest that selection hasn't allowed plants to create the same biomass with less water. Thank you for this conversation -- writing this email really made me think. Merran - No virus found in this message.
[ECOLOG-L] Bug Map of the US for Fieldwork?
Hey all, Would anybody be interested in putting together a bug map based on field experiences? It might be neat (albeit questionably legitimate and useful) to compile a GIS database of where what types of annoying bugs (e.g. mosquitoes, black flies, etc...) are active, and when. You know - for posterity's sake. A really bear-bones mockup would be to fill up a spreadsheet like this: https://docs.google.com/spreadsheet/ccc?key=0AvrkauqNoLYcdDlZR0F2ZVZYOE9HRTVzMXFLMG9fOXc Anybody have a better idea for how to do this? Adam
[ECOLOG-L] Frankincense trees bordering extinction...
http://www.guardian.co.uk/world/2011/dec/21/frankincense-production -- Clara B. Jones Twitter: http://twitter.com/cbjones1943 Cell Phone: 828-279-4429
[ECOLOG-L] Postdoc: Lake Baikal: Dimensions of Biodiversity
Postdoctoral Fellow Lake Baikal: Dimensions of Biodiversity A two-year postdoctoral fellowship position is available at the Dept of Biological Sciences at Wellesley College to co-lead a NSF-funded project on plankton biodiversity at Lake Baikal, Siberia. The goal of this multidisciplinary, multi-institutional project is to determine if the genetic and functional diversity of endemic plankton species will allow them to adapt and persist in a changing climate or whether they will be replaced by cosmopolitan species. Research on-site at Lake Baikal and at Wellesley College will quantify functional and taxonomic diversity of Baikals zooplankton. This project will be carried out in collaboration with Dr. Marianne V. Moore, Wellesley College, and other participating faculty and students at Michigan State University, UC-Santa Barbara, University of Texas, and East Tennessee State University. In addition to pursuing the projects core research questions, the candidate will also have the flexibility to develop their own independent research project. Requirements: · Ph.D. in aquatic ecology or limnology · Experience culturing zooplankton in the laboratory and conducting laboratory experiments with plankton · Strong quantitative skills · Record of peer-reviewed publication · Willingness to spend 3 months each summer and 1-2 weeks in winter at Lake Baikal · Interest in learning Russian and experiencing Russian culture A starting salary of $50,000 per year plus health and dental insurance will be provided. Applicants should attach their CV to an email describing their research interests and career goals, starting date availability, and contact information for three references. Send this email to mailto:mmo...@wellesley.edummo...@wellesley.edu with the subject line Baikal postdoc application. Please feel free to ask questions about your fit to the position before applying. Start date is negotiable, ideally March 1, 2012. For a project abstract, see: http://www.nsf.gov/awardsearch/showAward.do?AwardNumber=1136657http://www.nsf.gov/awardsearch/showAward.do?AwardNumber=1136657 For more information about the history of this Russian-American collaboration, see: http://www.nytimes.com/2008/05/06/science/earth/06lake.htmlhttp://www.nytimes.com/2008/05/06/science/earth/06lake.html Several papers authored by members of this US-Russian collaboration: http://www.wellesley.edu/Biology/Faculty/Mmoore/publications.htmlhttp://www.wellesley.edu/Biology/Faculty/Mmoore/publications.html
[ECOLOG-L] Abstract submission open for Intl. Statistical Ecology Conference 3-6 July 2012 in Norway
Submission of abstracts is now open for the third biennial International Statistical Ecology Conference will be held 3-6 July 2012, hosted by the Centre for Ecological and Evolutionary Synthesis at the Department of Biology of the University of Oslo. The conference location will be the Sundvolden Hotel outside Oslo. We have an extraordinary group of plenary speakers, whose presentation topics are: - Nils Chr. Stenseth, Univ. of Oslo (Norway): Opening remarks - Steinar Engen, Norwegian Univ. of Science and Technology (Norway): stochastic age-structured modelling, including dynamics, genetics and some estimation - Rachel Fewster, Univ. of Aukland (N.Z.): genetics in statistical ecology - Joanne Flemming, Dalhousie University (Canada): The Ocean Tracking Network: visualization tools and novel analyses for acoustic tracking data - Otso Ovaskainen, Univ. of Helsinki (Finland): the analysis of spatial data: individual movements and species and community models - Andre Punt, Univ. of Washington (U.S.): estimating precautionary thresholds for US west coast fisheries - Andy Royle, Patuxent Wildlife Research Center (U.S.): Incorporating auxiliary spatial information in capture-recapture models - Len Thomas, Univ. of St. Andrews (Scotland): The future of statistical ecology Training workshops will also be held prior to the conference: - AD Model builder (30 June - 1 July at Finse): Mark Maunder, Hans Skaug and Andres Nielsen - Hierarchical modelling and R-package 'unmarked' (2 July at Finse): Andy Royle and Richard Chandler - Population genetics for statisticians (2-3 July at Sundvollen): Rachel Fewster and Arnaud le Rouzic - Model selection (3 July at Sundvollen): Nils Lid Hjort The local organising committee has negotiated low rates for accommodation at the conference hotel. There is also a conveniently located camping venue with a choice of 4-6 person cabins. Attendees from developing countries can submit applications for stipends. Abstract submission deadline is 20 January 2012. Further details are available at the conference website http://www.cees.uio.no/isec2012/
[ECOLOG-L] Postdoc position - ecosystem services, economics, engineering
Incorporating Ecosystem Services into Restoration Assessment and Targeting Applications are invited for an interdisciplinary Postdoctoral Associate position at the University of Maryland Center for Environmental Sciences, Chesapeake Biological Lab, in Solomons, MD. The candidate will work with Dr. Lisa Wainger (waingerlab.cbl.umces.edu) and Dr. Margaret Palmer (www.palmerlab.umd.edu) to develop an analysis framework, including model and database components, for assessing ecosystem services to inform restoration policies. Ecosystem services are increasingly becoming the currency for measuring the potential benefits of restoration and preservation decisions, yet rigorous and systematic guidance for their measurement remains elusive. This effort will involve leveraging existing literature, data and models to develop a guiding framework for ecosystem service measurement that is specific to the needs of US Army Corps of Engineers for evaluating aquatic restoration projects. Other ongoing research is developing integrated ecological and economic models to demonstrate cost-effective and evidence-based approaches for ecosystem service measurement using case studies in invasive species management, wetland mitigation and water quality trading or offsets. Successful applicants will be expected to integrate ongoing research to develop conceptual approaches and empirical models for measuring selected ecosystem processes in a manner that reflects socially beneficial outcomes. The applicant will be responsible for producing literature summaries, databases and models through collaborative efforts with other researchers, modelers and model end users. Field work is not expected but may be possible, if desired. The appointment will initially be for one year, with possibility of renewal. The position offers a competitive salary plus benefits. Start date is flexible but current or near-term availability is desirable. Applicants must have a Ph.D. in a relevant area such as economics, decision science, engineering, or ecology; strong analytical skills including statistical modeling; interest or experience in environmental policy; and excellent communication skills. Applications, including a cover letter, CV, one-page summary of research interests, and the names and addresses of three references to: art...@cbl.umces.edu. Please reference: ARS - Wainger in the subject line. Applications should be submitted by January 23, 2012. UMCES is an AA/EOE/ADA employer; women and minorities are encouraged to apply.
Re: [ECOLOG-L] Plant Physiology Drought tolerance Re: [ECOLOG-L] course and symposium on plant breeding for drought tolerance
To All A comparison of Opuntia productivity to C3 and C4 plants, under both natural and cultivated conditions, was done in the early 90's by Park Nobel as part of a long term investigation of the physiology of Opuntia. I am writing from a place where I don't have access to the papers (but I do have the references: Nobel, PS, E Garciamoya, and E Quero. 1992. The high annual productivity of certain agaves and cacti under cultivation. Plant, Cell and Environment 15(3). pp329-335. Nobel, P. S. (1991). Achievable productivities of certain CAM plants - basis for high values compared with C3 and C4 plants. New Phytologist 119:183-205.). From what I can remember, the productivity of CAM plants was remarkably high. Remember what happened in Australia! Your assumptions throughout here seems to be that productivity in deserts is limited by physical factors and that may not be true. The real problem here is that we are anthropomorphizing the idea of stress. The idea needs to be one that can be applied to specific situations, not cofining it to a generalization like deserts are stressful environments. Stress seems possible in all environments, native or otherwise. Are not some of our native oaks under much stress now in their native habitat with the addition of sudden oak death and gypsy moths? Perhaps stress needs to be tied to phylogeny as much as to environment. As for the theoretical basis for engineering or selecting for drought-tolerance, there seems to be much that might be done to me. Drought adaptations found in some lineages might be transplanted into other lineages through engineering. Fundamental changes might be considered, such as engineering rubisco's ability to discriminate between CO2 and O2. I am not a plant physiologist but I think lots of genetic variation with regard to productivity under drought conditions exists and, if I am right, then there is a basis for hoping that a particular plant species might be induced to maintain productivity at low levels of water availability. I may be wrong (and perhaps I missed the beginning of this thread) but I seem to detect a worry that we are trying to expand biofuel agriculture onto land now not utilized for agriculture. This seems like a separate issue to me and one that deserves its own thread. Phil Ganter Biological Sciences Tennessee State University On 12/21/11 12:42 AM, Wayne Tyson landr...@cox.net wrote: Ecolog: Additional responses to Merran: I very much appreciate Merran's thoughtful response. I have made similar observations, but I do not know of any studies which have settled this matter. I remain open to enlightenment. I will attempt to do justice to Merran's contributions, but am doubtful that I can accomplish that in one or two emails. I hope that Merran and others, particularly some apparently highly qualified individuals who have contacted me off list with some very provocative ideas. In terms of the evolution of C4 plants from C3's and the abundance of the former in the tropics, I see further fertile fields for research. This may open a whole additional can of worms, but might it be that C4 evolved via a mutation that ALSO worked in more mesic circumstances rather than arising only in xeric environments? But this is too much and too distracting for now, and perhaps worthy of a spin-off thread? Later. A saguaro is bigger than a sagebrush, but it took longer for it to get that way? --Merran Exactly! And with respect to KY bluegrass and buffalo grass, I presume that productive potential (quantity) is not as important as persistence under stress. But are not lawns under continuous luxury-consumption (quantity) conditions by definition? I presume that Merran will stress his buffalo grass, and not have to mow down the excess biomass as much (quality, in Merran's eyes, not quantity, which is irrelevant in that context. And context is everything, eh? Let us not neglect RATE calculations, especially if we're going to get picky (nothing wrong with that)? I forgot to mention unit/time, and thanks to Merran for correcting my oversight. I hope someone will clear up the confusion about how selection hasn't allowed plants to create the same biomass with less water as Merran also points out. Any if it has, which plants they are and how much more efficient they are in producing more units of biomass IN LESS TIME OR THE SAME TIME as less efficient non-drought-tolerant plants. WT - Original Message - From: Merran pantscr...@gmail.com To: ECOLOG-L@LISTSERV.UMD.EDU Sent: Tuesday, December 20, 2011 8:16 PM Subject: Re: [ECOLOG-L] Plant Physiology Drought tolerance Re: [ECOLOG-L] course and symposium on plant breeding for drought tolerance Isn't drought tolerance defined by a plant's water use efficiency? C4 plants have the ability to fix 2 or 3 times more carbon with the same amount of water not because they use less water in photosynthesis, but because they limit photorespiration and the
Re: [ECOLOG-L] Plant Physiology Drought tolerance Re: [ECOLOG-L] course and symposium on plant breeding for drought tolerance
[We obviously need more plant physiological ecologists on this list. I'm not one, and I'm going off the top of my head, so please forgive any errors I might make.] Water-use efficiency is not synonymous with drought tolerance - it's a measure of the amount of biomass a plant can make while spending a unit quantity of water. It's actually quite easy to alter WUE because the vast majority of the water isn't spent making biomass, it's lost when the plant opens its stomata. As carbon dioxide concentrations increase, WUE increases - plants can fix more biomass per unit time that their stomata are open. If water is more limiting than carbon, chances are that the plant will spend less time with their stomata open, and thus be better able to tolerate drought. So increased WUE may be a mechanism of drought tolerance, but it does not have to be. There are (as you mentioned) many other ways that a plant can increase its WUE. The distribution of stomata can do this (more on the underside of the leaf, fewer on the upper surface), the density of hairs on a leaf, the way the plant alters leaf orientation in response to water loss. Sunken stomata are another important way to conserve water. The age of leaves can also affect WUE, since older stomata are leakier when their closed. Now obviously none of this is free to the plant - most take resources to make, and for the most part, limiting the rate of water loss will also limit the rate of CO2 uptake. But these relationships are not linear, and relative humidity varies more than CO2 concentration. So, depending on the environment, a plant can break even or gain a substantial advantage through traits like these. When you're talking about growing crop plants, you're talking about minimising the cost of many of these trade-offs through human intervention. Many of these sorts of traits are variable within species, and some of them are induced responses to drought - so there's a fairly large range of variables that a plant breeder can work with (assuming that these traits exist in the crop that the breeder is working with - which is, of course, not a given. But it's important to remember that drought tolerance is far more than WUE. It's also a matter of the ability to a plant to forage for soil water, and to extract that water from drying soils. Plants in dry environments tend to allocate a larger proportion of their belowground processes. This may take the form of deep roots that are able to tap deep soil moisture, or it may be allocating sugars to mycorrhizae or proteins to the rhizosphere. Again, if water is not limiting, there's no advantage to this, but if it is, the payoff is likely to exceed the investment in sugars. Water potential is another important factor. The ability of plants to extract water from the soil is governed (at least in part) by the osmotic gradient between the root hairs and the soil water. [Yes, I know, this is a gross simplification.] Plants that can generate lower water potentials can extract water from drier soils (famously on the order of -9MPa for creosote). Obviously the ability to tolerate such low water potentials must come at some cost, but these are trade-offs that a plant can work to its advantage (in certain environments). Again, these are (presumably) things that one could alter in a plant-breeding programme. [C4 and CAM are a whole different set of issues, but this message is already too long.] Quoting Merran pantscr...@gmail.com: Isn't drought tolerance defined by a plant's water use efficiency? C4 plants have the ability to fix 2 or 3 times more carbon with the same amount of water not because they use less water in photosynthesis, but because they limit photorespiration and the amount of water lost through their stomatas. So they do fix more more carbon with less water, but unless the climatic conditions are perfect I don't think the advantage is really that great. I'm fairly sure that the tropics have a greater abundance of C4 plants than the American deserts, and saltbushes (C4, right?) are not usually that much larger than sagebrushes.. There must be other limiting factors. It's my understanding as well that CAM photosynthesis is not the same as C4 photosynthesis -- I've read that it is a different, even more efficient process. It occurs in desert succulents and allows the plants to open their stomatas only at night, thus losing far less water to transpiration. The CO2 is stored as an acid and metabolised the next day. These plants can breath in up to 40 times more Carbon dioxide than C3 plants with the same water loss. However efficient these plants are, they are also very slow-growing -- something that I have never fully understood. I think that there's a low limit to their acid-storing capabilities. So they lose less water in exchange for performing less photosynthesis each day, but are still creating the same
[ECOLOG-L] Position Announcement: Field Technician for Least Tern and Wilson's Plover Resighting
Title: Field Technician for Least Tern and Wilson's Plover Resighting Agency: Virginia Polytechnic Institute and State University Location: near Cape Lookout National Seashore, NC Job Type: Full-time, temporary Duration: 15 April-15 Aug, 2012. Application Deadline: 15 Jan Job Description: Assist graduate students in the 3rd year of a collaborative research project investigating the behavioral and demographic effects of military overflights on shorebirds. Focal species include Least Tern and Wilson's Plover. Primary duties include re-sighting color-banded Least Terns and Wilson's Plovers. Additional duties may include surveying waterbird colonies. Qualifications: B.S. in Wildlife Science or related field and previous field experience re-sighting color-banded birds. Experience surveying colonial waterbirds is preferred but not required. Successful applicant will be adaptable, detail-oriented, enthusiastic, and able to work and live harmoniously with others on a remote barrier island in Park Service housing. A valid driver's license is required and experience operating 4WD vehicles, ATVs and boats is desired. Salary: $400/week + free housing contact: Send cover letter and resume with academic background, work experience, and contact information for 3 references to Matthew Hillman (mhill...@vt.edu) and Audrey DeRose-Wilson (ader...@vt.edu), or mail application to Department of Fisheries and Wildlife Sciences, Virginia Tech, 100 Cheatham Hall, Blacksburg, VA 24061-0321 (electronic applications preferred). Virginia Tech is an EO/AA employer.
[ECOLOG-L] JOB AD: EVOLUTION OF ORGANISMAL DIVERSITY, UNIVERSITY OF CALIFORNIA, DAVIS
JOB ADVERTISEMENT EVOLUTION OF ORGANISMAL DIVERSITY, UNIVERSITY OF CALIFORNIA, DAVIS The College of Biological Sciences, University of California, Davis invites applications and nominations for a tenure-track position in the Department of Evolution and Ecology at the ASSISTANT level, with the possibility of ASSOCIATE appointment with tenure. Candidates must have a Ph.D. (or equivalent) in the biological sciences or related fields. They should have a strong record of integrative approaches to the evolution of organismal diversity. We seek candidates with expertise in the organismal biology/natural history of a multicellular group, and whose research uses genomic data in an explicitly phylogenetic context to address questions in macroevolution, ecology, behavior and/or development. The successful candidate will be expected to teach in the department's undergraduate program and in the Population Biology Graduate Group and should be committed to departmental service. Applicants should submit materials online at: https://recruitments.ucdavis.edu/PositionDetails.aspx?PositionID=85amp;Title=Asst/Assoc- Professor-%28Tenure-Track%29 which contains additional information about the position. These should include: curriculum vitae, description of current and projected research, summary of teaching interests and experience, and up to five publications. Applicants should also provide the information requested for three referees. Once entered, referees will be prompted by email with upload instructions for their letters. Closing Date: Open until filled, but all application materials, including letters of recommendation, must be received by February 6, 2012, to assure full consideration. Administrative contact: Carla Munoz (camu...@ucdavis.edu). Faculty contacts: Peter Wainwright, Michael Turelli, and Rick Grosberg. The University of California is an Equal Opportunity/Affirmative Action Employer with a strong institutional commitment to the development of a climate that supports equality of opportunity and respect for differences.
[ECOLOG-L] Two Red Squirrel Field Technician Positions Available
Two field assistant positions are available to assist with a graduate student project about how experimental manipulation of hormone levels affects life history traits in female North American red squirrels in the Yukon, Canada. One positions will run from early March 2012 to late June 2012 and the second position will run for a shorter duration from early April to late May. However, the exact duration of the positions will be determined later. Duties of these positions include live-trapping and handling red squirrels, radio telemetry, behavioral observations, and collecting fecal and plasma samples. These data will be collected as a part of a graduate research project but the successful applicants will also contribute to long-term data collection for the Kluane Red Squirrel Project (www.redsquirrel.ca). Applicants should be physically fit, capable of 1) snowshoeing (breaking new trail) several hours per day, 2) working in very cold to mild weather (-40 to 20 C), 3) climbing trees, and 4) working alone in areas with grizzly and black bears. Successful applicants will be provided with extensive training in live-trapping, radio telemetry, collecting fecal and plasma samples, and performing behavioral observations. However, technicians will work largely independently and are expected to be hard working and dependable. There may also be opportunities for independent research projects (inquire). The position pays $1500-1800/month and all food and lodging will be provided at our remote field camp. This means that you get free good food and lodging during the terms of appointment! Successful applicants must also supply their own field equipment (sleeping bag, boots, appropriate field clothing, etc.). Required Qualifications 1) Eligible to work in Canada 2) Valid drivers license 3) Capable of snowshoeing and hiking 15 km/day, climbing trees, working in the winter during extreme cold 4) Capable of handling peanut butter (no nut allergy) 5) Capable of working and living with others in close quarters 6) Capable of working independently in a remote location Desired Qualifications 1) Degree or relevant experience in ecology, zoology, behavior, physiology, etc. 2) Previous field experience handling small mammals or other animals 3) Experience with radio telemetry 4) Experience with Microsoft Access 5) Interest in future graduate research opportunities For more information on the Kluane Red Squirrel Project, go to www.redsquirrel.ca To apply for this position, please send a Cover Letter, CV, and the contact information for 3 references to Ben Dantzer at dant...@msu.edu Application deadline is January 20 2012
[ECOLOG-L] 2012 Six Month Crew Member
Description: Spend six months working and camping at some of Nevadas premier natural areas. Serve alongside volunteers from across the country while making a lasting contribution to Nevadas natural heritage. Gain valuable field experience while working on habitat improvement, restoration, and recreation projects with the U.S. Forest Service, Bureau of Land Management, National Park Service, and local and state agencies. Provide national service with your environmental restoration efforts and work in a diverse and beautiful array of desert, mountain and alpine habitats. Compensation: This is an AmeriCorps volunteer position, and candidates will receive a living stipend of $7,000 for the six months time period. This is not an hourly wage or a salary and is paid to members bi-weekly throughout the entire year to assist with living expenses. Upon completion of AmeriCorps national service contract, members shall receive an additional education award in the amount of $2,775 that can be used for paying off student loans, or paying tuition for a Title IV accredited college. Timeline: February 20, 2012 August 16, 2012 Conservation Projects: Trail building and rehabilitation Exotic species removal Forest thinning Habitat restoration Riparian rehabilitation Illegal road decommissioning Qualifications: To qualify, you must be over 17 years of age and a US citizen that has received a high school diploma or GED. All offers of employment are conditional upon completion of an acceptable check of the National Sex Offender Public Registry (NSOPR) and federal criminal background check. Essential Duties: Percentage of time spent on: lifting an carrying 70%, traveling 20%, Hiking 10% Lift 25lbs continuously and 50lbs occasionally Maintaining a positive and professional attitude at all times while providing service Communicating with agency project staff Complying with both production and quality work standards established by NCC administration, crew supervisors and project partners Camping up to seven nights in wilderness setting without formal restroom facilities and running water Contributing to basic duties at the campsite including cooking, cleaning and organizing crew equipment Work Schedule: Schedules will be dictated by project site and the distance between the field station. Many crews will be assigned to several projects throughout the season, therefore there may be a mixture of both 4 and 8 day tours. All schedules are subject to change due to unpredictable circumstances. You will start your term of service based from our Las Vegas, NV field station. Due to the seasonal nature of field work in Nevada you may be required to relocate during the term. Teams will provide service in Southern Nevada based in Las Vegas and will remain there through May when they will be given the option to continue serving in the Las Vegas area or relocate to our Reno, NV field station for the summer months. The NCC will help during the transition time with housing recommendations. We will not provide housing nor sign leases, but we can assist with identifying housing options. Training: Members will attend an orientation session on Monday, February 20, 2012 where they will receive background information regarding AmeriCorps national service and the Nevada Conservation Corps prior to joining their team in the field. Possible Project Site Locations: Great Basin National Park, Spring Mountains NRA, Lake Mead NRA, Ash Meadows National Wildlife Refuge, Mt Rose Wilderness Area, Ruby Mountains, and Schell Mountain Range in eastern NV. To Apply: Step 1: Click here: https://my.americorps.gov/mp/listing/viewListing.do?id=43379 Step 2: Click Apply then register. Step 3: Once registered login and complete the application. Step 4: Click the Search Listings link and search for program name: Nevada Conservation Corps Step 5: Click on the appropriate position title, then hit the Apply Now button at the bottom of the listing. Please direct all questions regarding the application process to Bridget Walden at bwal...@thegreatbasininstitute.org. These AmeriCorps positions are made possible by a generous grant from Nevada Volunteers. This program prohibits discrimination on the basis of race, religion, sex, marital status, sexual orientation, or disability. Persons with disabilities are encouraged to apply.
[ECOLOG-L] Job opening: Field Tech for longleaf pine restoration in South Carolina
Position Opening: Field Technician position: Longleaf pine restoration The Savannah River Site, South Carolina We seek to fill a field technician position for a large- scale experiment on the restoration of longleaf pine plant communities in the Southeastern United States. Primary job duties will include setting up and maintaining experimental plots, soil processing, seed collection and cleaning, data entry and various other tasks required for experimental studies of plant community restoration and plant- animal interactions. Technicians will be involved in supplemental activities focused on restoring the imperiled longleaf pine understory. The position will begin March 2012, and will last for 3-9 months. Pay rate will be $10-12/hr commensurate with experience. The technician will work at the Savannah River Site, live in a town near the site (Aiken or Ellenton, SC; Augusta, GA), and will join a team of two principal investigators (John Orrock at University of Wisconsin-Madison and Lars Brudvig at Michigan State University) a postdoc (Chris Habeck, at Michigan State University) and a Lead Technician (Joe Ledvina, at Michigan State University). Housing is not provided, although low cost options are plentiful. Successful candidates will have some background in ecology, biology, or a related discipline. All applicants must be able to endure hot, humid conditions and long hours in the field. Previous field research experience required. Botanical experience would be desirable, but not required. Michigan State University is an equal opportunity employer. Women and minorities are strongly encouraged to apply. *Because the research site is a highly secure area run by the federal government, non-United States citizens may have difficulty gaining clearance to work there. To apply, please email a CV or resume and letter describing past experience, why this position is interesting or important to you, dates of availability, and contact information with email addresses for two references to Chris Habeck: habec...@msu.edu. The position will be filled when a suitable applicant is found. Applications submitted after February 1, 2012 will not be considered. Chris Habeck Remnant Expansion Project Postdoctoral Research Associate Department of Plant Biology Michigan State University
[ECOLOG-L] Chicago Botanic Garden Summer 2012 REU
Dear Ecolog, This summer, the Chicago Botanic Garden and partner institutions will host 10 NSF-REU interns (Research Experiences for Undergraduates) conducting research under the broad theme of PLANT BIOLOGY AND CONSERVATION, from genetic to ecosystem levels of inquiry. Potential projects include work in soil ecology, systematics, reproductive biology, biogeochemistry, restoration ecology, pollinator ecology, and other fields. Students will gain laboratory and field experience, participate in professional development activities, help mentor high-school student researchers, and enjoy a fun social environment. Participants should be U.S. citizens or permanent residents who will be enrolled as undergraduates after summer 2012. They will receive a stipend of $4,750 and room and board at a local college. Costs of travel to and from Chicago will be covered. We encourage applications from students who are members of groups underrepresented in the sciences and students who have limited research opportunities at their home institutions. The application deadline is January 31, 2012, and the 10-week program will run from June 11-August 17, 2012. We invite interested undergraduates to find more information and apply at http://www.cbgreu.org. Questions can be directed to i...@cbgreu.org. We also ask faculty, postdocs, graduate students, and other undergraduate mentors to please help us spread the word about this exciting opportunity to exceptional undergraduates. Evelyn Williams, Ph.D. Chicago Botanic Gardens REU Experience http://www.cbgreu.org/ i...@cbgreu.org
[ECOLOG-L] Internship opportunity; Yellowstone Raptor Initiative (Yellowstone Nat. Park)
Raptor Field Intern position: 2012 field season Yellowstone National Park Yellowstone Raptor Initiative The Yellowstone Raptor Initiative (YRI) will host two intern positions during the 2012 May-August field season; start and end dates negotiable. Interns will assist YRI raptor biologist with tasks including (at least) locating raptor nesting territories, determining nesting chronologies and fledging success. Field work in Yellowstone National Park is amazing, but occurs in mountainous terrain at +2000 m elevations in habitat where grizzly bear, mountain lions, wolves, bison and elk are not uncommon. Interns will be provided a daily living stipend, and a bed in dormitory style housing. The preferred candidate should understand the following situational requirements: 1) Interns will be expected to hike at least 1-16 km/day with 8 - 22 kg backpacks for up to five days per week over remote, non-trailed habitat. There will be considerable scrambling over rocks, downed trees, and crossing of creeks and streams. Interns will also face long periods of sitting at exposed (wind, sun, precipitation) observation points that may have biting insects. 2) Weather conditions will range from pleasant, to snowy, windy, and potentially drenching afternoon thunderstorms. Temperature extremes from - 0° to +30° C are not uncommon. 3) Intern should be comfortable in habitat with potentially dangerous wildlife, and should be able to remain calm in hazardous situations. 4) Intern should have 20/20 vision (corrected or natural) and good to superb hearing. 5) Intern should have prior outdoor experience, including skills related to backcountry camping, backcountry navigation (without GPS), basic wilderness survival, and basic first aid/CPR. 6) Intern should have own basic field gear (i.e. medium sized backpack, field shoes/boots, raingear, cold weather gear, water bottles, etc. (we will provide a recommended equipment list to the selected interns). 7) We would prefer an intern who already has some raptor field experience. We will select an intern who is known to be friendly, kind, cheerful, mature, energetic, self-motivated, appropriate sense of humor, adaptable to varying circumstances, and willing to work long hours under sometimes difficult circumstances. Additionally, the selected interns should have an innate desire to learn from professionals about raptor ecology, as well as immerse themselves in the rich natural and cultural history of Yellowstone National Park. 8) Interns must be able to communicate politely to National Park visitors, staff, and other YRI cooperators at all times. 9) Intern should be able to speak and write in English. 10) Intern should have the maturity to cope with group living situations (i.e. dormitory housing, multiple people per room, varied personalities, and levels of cleanliness). 11) Interns must be at least 18 years old by start of internship. If under 21, no alcohol use. Failure to comply will necessitate immediate termination of internship. Drug and/or alcohol abuse will necessitate immediate termination of internship. 12) Valid state or international driver’s license preferred. 13) We will work with University or College professors if intern wishes to acquire academic credit. Please send, no later than 30 March 2012; a) CV or Resume, b) names and current contact information of three suitable references, and c) a short letter outlining your interest and qualifications to: Dr. Douglas Smith, Yellowstone Raptor Initiative, Yellowstone National Park, Mammoth, WY 82190; or doug_sm...@nps.gov
[ECOLOG-L] Graduate Research Assistantship in Fire Ecology
Graduate Research Assistantship in Fire Ecology I seek a MS student to research the effects of prescribed burning on ecosystem services of oak forests and savannas of south-central USA. The ecotone between the eastern forest and southern Great Plains has been subjected to anthropogenic burning for thousands of years. Because of recent changes in the fire regime there is growing interest in using prescribed burning to manage forests, savannas and grasslands for maintenance and enhancement their ecosystem services. A MS student is sought to conduct independent research on prescribed burning effects on ecosystem structure and function. The research will be done within the context of a larger DOD project concerning how to manage the carbon footprint of forests and savannas. The MS Graduate Research Assistantship (GRA) stipend will be $15,500 per year. The GRA will begin in mid-May 2012 and will be renewed for two years provided satisfactory progress in the project. GRAs are offered with tuition waivers. Please contact: Steve Hallgren, Oklahoma State University, 405-744-6805, steve.hallg...@okstate.edumailto:steve.hallg...@okstate.edu
[ECOLOG-L] Position Announcement - SALT MARSH BIRD BANDER/TECHNICIAN
SALT MARSH BIRD BANDER/TECHNICIAN Position Description: US Fish and Wildlife and The University of Rhode Island are seeking an individual to assist in a collaborative project with the RI National Wildlife Refuge Complex in monitoring salt-marsh breeding birds and overall salt-marsh ecological integrity. Responsibilities include leading a 2-person crew to carry out Saltmarsh Sparrow mist-netting and banding, nest searching and monitoring and conducting secretive marsh bird surveys. Qualifications: Applicants must possess the ability to identify eastern birds by sight and sound; to work outdoors in all types of weather conditions, especially heat and humidity; to endure biting insects; to work well with others, to collect complete and accurate data in the field without direct supervision; and to hike over uneven terrain while carrying equipment. Applicants also must possess a valid driver’s license and be willing to assist with other refuge projects such as invasive plant eradication and Piping Plover monitoring. Must have prior experience mist-netting and banding songbirds and conducting point counts. Previous kayaking experience preferred. Duration: One position available May 14 - August 17. Salary: $2100/month plus possible housing. Send letter of interest, resume and contact information for 3 references to Rhonda Smith, 50 Bend Road, Charlestown, RI 02813 OR email materials to rhonda_sm...@fws.gov. Application deadline is January 27.
[ECOLOG-L] MSc / PhD position at the Department of Entomology, University of Manitoba
Interested in studying insect ecology at multiple spatial scales? Potential research topics include relationships among landscape structure, natural enemy biodiversity, and herbivore insect control; multi-trophic interactions within natural enemy guilds; and sustainable management of agricultural pests. We combine field and lab experiments to explore these topics. Start summer or fall 2012. For more information contact Ale Costamagna, ale_costama...@umanitoba.ca, and see the lab website for more research themes and publications ( http://www.umanitoba.ca/afs/entomology/staff/faculty/Costamagnapage.html).
[ECOLOG-L] KBS 2012 SUMMER PROGRAMMING
ANNOUNCING: Summer 2012 Field Courses and Undergraduate Programming Kellogg Biological Station http://www.kbs.msu.edu Dear Colleagues, The Kellogg Biological Station (Michigan State University) is excited to announce its summer programming. We offer field based undergraduate and graduate courses and NSF REU's. We are especially excited to announce our Undergraduate Research Apprenticeship program, aimed at early career students combining class work with a heavily mentored research experience. Our courses are: Plant Systematics Ecology/Ecology Lab Grazing and Robotic Milking Field Ecology and Evolution Aquatic Entomology Biogeochemistry Social Agroecological Systems ELME (Enhancing Linkages Between Mathematics and Ecology) Eminent Ecologist Seminar Series http://www.kbs.msu.edu/education/summer-courses More information on REU's can be found here: http://www.kbs.msu.edu/education/internships-reu/nsf-reus-for-undergrads And more information on our Undergraduate Research Apprenticeship can be found here: http://www.kbs.msu.edu/education/internships-reu/research-apprenticeship Please forward this information on to colleagues or students you think might be interested. Thank you for your help! Rachel Prunier, PhD. Assistant Director for Education and Research Associate Kellogg Biological Station 3700 East Gull Lake Drive Hickory Corners, MI 49060 prun...@msu.edu (269) 671- 2350 *** An inconvenience is only an adventure wrongly considered. G. K. Chesterton
[ECOLOG-L] May Expedition to Kazakhstan’s Zailiyski Alatau gr oup willing to collect data.
We have a team leaving in May 2012 for the Tian Shan Mountain Range. They will be climbing and skiing several unskied routes in the Zailiyski Alatau group including on Pik Talgar. The team has volunteered to collect data while they are out there, and we are wondering what particular interest there is in this region. Our team has extensive experience in GIS and is willing to collect data on anything that may be needed. Please send ideas. www.adventureandscience.org/find-an-adventurer.html -- Gregg Treinish Executive Director Adventurers and Scientists for Conservation 2008 National Geographic Adventurer of the Year 406.579.9702 www.adventureandscience.org
Re: [ECOLOG-L] Plant Physiology Drought tolerance Re: [ECOLOG-L] course and symposium on plant breeding for drought tolerance
To Wayne and others: Sorry about the C4/CAM confusion. It has been many years since I have thought about them and I forgot some important distinctions (but it did seem to make the thread come to life). Wayne, in answer to your question regarding this question I put forth: ...Is this any less plausible than other manipulations that have been carried out in the past that have resulted in increased yields? You will notice that it makes no reference to water use. I was addressing in a general way the fact that artificial selection WORKS. Wayne, your questions seemed to imply a null hypothesis that selection or genetic engineering CANNOT increase plants' productivity under low-water conditions. It seems to me ALL physiological processes are subject to alteration, which in turn can influence the efficiency and productivity. Has anyone ever found a genetic trait for which there was no genetic variability or that did not respond at all to selection? Can anyone seriously believe that all plants are equally efficient at surviving, photosynthesizing, and producing biomass with low water availability? If we can hypothesize two plants that differ in this regard, we can imagine that there are manipulations to make the one more like the other. It seems to me that the plausible starting assumption is that the yields of crop plants under drought conditions CAN be increased. If serious attempts show that it cannot be done, that will be some sort of a revolution in our understanding of physiology and and evolution. Martin M. Meiss 2011/12/21 Ganter, Philip pgan...@tnstate.edu To All A comparison of Opuntia productivity to C3 and C4 plants, under both natural and cultivated conditions, was done in the early 90's by Park Nobel as part of a long term investigation of the physiology of Opuntia. I am writing from a place where I don't have access to the papers (but I do have the references: Nobel, PS, E Garciamoya, and E Quero. 1992. The high annual productivity of certain agaves and cacti under cultivation. Plant, Cell and Environment 15(3). pp329-335. Nobel, P. S. (1991). Achievable productivities of certain CAM plants - basis for high values compared with C3 and C4 plants. New Phytologist 119:183-205.). From what I can remember, the productivity of CAM plants was remarkably high. Remember what happened in Australia! Your assumptions throughout here seems to be that productivity in deserts is limited by physical factors and that may not be true. The real problem here is that we are anthropomorphizing the idea of stress. The idea needs to be one that can be applied to specific situations, not cofining it to a generalization like deserts are stressful environments. Stress seems possible in all environments, native or otherwise. Are not some of our native oaks under much stress now in their native habitat with the addition of sudden oak death and gypsy moths? Perhaps stress needs to be tied to phylogeny as much as to environment. As for the theoretical basis for engineering or selecting for drought-tolerance, there seems to be much that might be done to me. Drought adaptations found in some lineages might be transplanted into other lineages through engineering. Fundamental changes might be considered, such as engineering rubisco's ability to discriminate between CO2 and O2. I am not a plant physiologist but I think lots of genetic variation with regard to productivity under drought conditions exists and, if I am right, then there is a basis for hoping that a particular plant species might be induced to maintain productivity at low levels of water availability. I may be wrong (and perhaps I missed the beginning of this thread) but I seem to detect a worry that we are trying to expand biofuel agriculture onto land now not utilized for agriculture. This seems like a separate issue to me and one that deserves its own thread. Phil Ganter Biological Sciences Tennessee State University On 12/21/11 12:42 AM, Wayne Tyson landr...@cox.net wrote: Ecolog: Additional responses to Merran: I very much appreciate Merran's thoughtful response. I have made similar observations, but I do not know of any studies which have settled this matter. I remain open to enlightenment. I will attempt to do justice to Merran's contributions, but am doubtful that I can accomplish that in one or two emails. I hope that Merran and others, particularly some apparently highly qualified individuals who have contacted me off list with some very provocative ideas. In terms of the evolution of C4 plants from C3's and the abundance of the former in the tropics, I see further fertile fields for research. This may open a whole additional can of worms, but might it be that C4 evolved via a mutation that ALSO worked in more mesic circumstances rather than arising only in xeric environments? But this is too much and too distracting for now, and perhaps worthy
