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] Conservation or just gardening?
Jason, And if a species is beyond saving with conservation, how worthwhile is it to save that species with gardening? At this point, it might be pertinent to ask what other species are dependent (for their life processes) on the gardened species. For example, is there an exclusive mutualism that needs to be preserved? Colleen Grant --- On Mon, 1/17/11, Jason Hernandez jason.hernande...@yahoo.com wrote: From: Jason Hernandez jason.hernande...@yahoo.com Subject: [ECOLOG-L] Conservation or just gardening? To: ECOLOG-L@LISTSERV.UMD.EDU Date: Monday, January 17, 2011, 5:08 PM This question is inspired by a conversation with a former employer. When do our interventions cease to be conservation and become gardening? For the sake of argument, I was taking the purist position: that ideally, we want to be able to put a fence around a natural area and walk away, letting nature manage it. But as my employer rightly pointed out, that is just not a realistic expectation in the 21st century, what with invasive species, systemic pollution, human pressures on surrounding areas, and countless other factors which will not go away. But of course, she also knew that there is a degree of intervention which crosses the line from conservation to gardening, that is, caring for a population that no longer participates in its ecosystem processes. There is, of course, a continuum of interventions. Removal of invasive competitors is a relatively light intervention; growing seedlings in a greenhouse and then planting them out is more intensive; maintaining an in vitro germplasm collection still more intensive. Are there any recognized criteria for determining the boundary between conservation and gardening? And if a species is beyond saving with conservation, how worthwhile is it to save that species with gardening? Can we determine when a species' only hope is gardening? Jason Hernandez Biological Science Technician, USDA Forest Service
Re: Ecosystem Integration with Landscaping Ecology and Public Relations Supporting efforts to promote the use of native plants
Dear Wayne You are right when you describe your dream of integrating ecology and landscape architecture as difficult to achieve. I offered the extension programs as one avenue among many available for those who want to try to make a difference. I understand your skepticism as my educational background is botany and ecology, not horticulture. (Yet, I also love raising my own vegetables hence the master gardener training.) Convincing new Las Vegas residents that they need to learn new landscaping concepts appropriate for the desert is a major portion of the work performed by the local Master Gardeners. The new residents move to the desert for the dry heat and sunshine, yet they still want their Kentucky bluegrass lawns and azaleas. Maybe ecologists need to be less adamant that plants in urban settings should be allowed to follow an unimpeded, natural life path. If a home owner in the Southwestern desert area plants a Larrea tridentata and keeps that Larrea pruned to 1 meter high, will that plant use more water that a Larrea allowed to naturally grow to 2 meters in height? I don't know, but I will argue that better a Larrea planted in that yard than a euonymus. Regarding landscape architects that look at site-specific species before consulting the nursery catalogs, are you familiar with the work being done at the Springs Preserve (www.springspreserve.org)? They are promoting use of Mojave Desert species and green building. Thank you for your interesting and informative response. Colleen Wayne Tyson [EMAIL PROTECTED] wrote: Dear Colleen Grant (certified Master Gardener but on 6-months leave from Southern Nevada Master Gardeners) I quite agree that a gentle approach needs to be used with home gardeners. In fact, I have long dreamt of the day when ecosystem restoration principles could be integrated into at least some parts of landscaping and gardening (not to mention integrated farming). I have, for example, shown people how to restore functioning indigenous (self-sufficient) ecosystems onto their roofs, landfills, subdivisions, pipeline row's, and roadway cuts, and am presently helping a landscape architect to transform most of a residential project to a self-sufficient complex of indigenous species, and, if we are lucky, a fully-functioning ecosystem. It is quite a challenge, however, to be gentle ENOUGH with folks who already know gardening and landscaping. The trouble is, those paradigms do not fit those of ecosystems. I have worked with native plant societies--folks DEDICATED to native plants, who LOVE native plants with a purple passion. Yet still they cling to the gardening paradigms, and are unwilling or unable to apply real ecology to their gardens. They simply can't believe that native plants can live without their care, much less believe that their care works strongly against ecosystem processes, that things like cultivation, irrigation, fertilization, and other maintenance are inimical to ecosystem processes. Nor will they accept any suggestion that Nature should do the selecting rather than themselves, even when exposed to concepts like modifying an indigenous ecosystem to suit their needs. The use of native plants idea has been around for at least a century, and has even gone through some pretty impressive fad periods (the nineteen-teens, twenties, and thirties), but the idea of one choosing individual plants that happen to meet one's fancy rather than those that are congruent with habitat conditions and organisms with which they have co-evolved has not caught on. 'Tis a pity, because if such a concept were only considered, the gardeners would find many pleasant surprises by giving Nature an opportunity to strut her stuff. If you suggest to most landscape architects, for example, that they follow the discipline that they FIRST consider whether or not a site-indigenous species will perform up to their own project requirements (this could be number seven on my SUSTAINABLE SITES INITIATIVE list) before they resort to nursery catalogs and gardening books, they will ignore you. NOTE: I would like to compile a list of landscape architects who do or will endorse and follow that one simple discipline--please help by sending me their names and addresses. Impatience and unfamiliarity seem to be the primary obstacles to this level of understanding, and the programs you describe are likely to help. But after 100 years or so of using native plants in gardens, I am not extra-hopeful that my dream of integrating ecology and landscape architecture beyond hyperbole will be achieved until the wells run dry, and perhaps not even then. But good luck with it anyway! WT At 03:12 PM 12/16/2007, Colleen Grant wrote: In urban areas across the country (United States), County Extension offices are actively working with landscapers to promote greater use of native plants. Sometimes classes and seminars devoted solely
Re: Supporting efforts to promote the use of native plants
In urban areas across the country (United States), County Extension offices are actively working with landscapers to promote greater use of native plants. Sometimes classes and seminars devoted solely to the topic are held, more often the information is integrated into presentations on pruning or irrigation. An ecologist willing to share his/her knowledge about native plants (with a gentle approach) would be welcomed as a valuable resource. A good way to reach the average home owner is through the Master Gardener programs available is all fifty states (United States). Master Gardeners answer help phone lines and have information booths with booklets and pamphlets at home shows, county fairs, and at plant sales. MGs also teach short classes to the general public at places such as public libraries, garden club meetings, landscaping seminars and public parks. Master Gardener programs are always associated with a land grant university so most of the literature dispensed is peer-reviewed and all the literature is research-based. Ecologists could help by teaching a short seminar (1-2 hours) to Master Gardeners, by being the guest speaker at a monthly meeting or co-authoring literature that will be dispensed to landscapers and the general public. Does this stimulate any other ideas on how you could help? If you think you can make a contribution through this venue, please contact the local County Extension Office and ask to speak with the Master Gardener Coordinator Colleen Grant (certified Master Gardener but on 6-months leave from Southern Nevada Master Gardeners)
Re: Pens or pencils for field notes
Dear William, The space pens are still sold. The website to buy directly from the company is http://www.spacepen.com/Public/Home/index.cfm Or if you happen to be vacationing in beautiful Boulder City, Nevada, you can visit the factory located at 711 Yucca. Not affiliated with the company, just a user of the product Colleen Grant William Silvert [EMAIL PROTECTED] wrote: As for the matter of pens, I am surprised that no one has mentioned the Fisher Space Pen, the one developed for use by astronauts. I had several and found them remarkably tough and versatile. Since I no longer live in the US I don't know whether they are still available or perhaps are sold under a different name, but I sure liked mine.
