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Abstract Detail



Physiological Section

Borer, Catherine [1], Cahoon , Aubrey Bruce [2], Miller, Joyce [3], Tate, Torri [1].

Documentation of foliar surface features for calcium tolerance of Poliomintha incana, from White Sands National Monument, an extremely high-calcium site.

Calcium (Ca) is an essential macronutrient, but its concentration must be maintained at low levels in the cytoplasm of all cells, to avoid Ca toxicity. This also allows cells to use Ca as a second messenger, for sensing and responding to many environmental signals. In recent work, we evaluated foliar partitioning in a range of plant species growing at White Sands National Monument, to determine possible mechanisms by which plants maintain labile Ca at sufficiently low levels to tolerate the extremely high calcium availability that results from soils that are largely comprised of gypsum (calcium sulfate). This earlier work demonstrated various mechanisms of Ca tolerance in the species we studied. Surprisingly, we found that two species maintained over 90 percent of their foliar calcium in a labile form, rather than chemically sequestering it, as is common in many other plant species. One of the two species with large amounts of labile Ca, Tamarix gallica, which is invasive in many areas, has been documented to tolerate saline soils by exuding excess salt via salt glands. However, to our knowledge, salt glands have not been described or documented to occur in the other species in this study with largely labile foliar Ca, Poliomintha incana. As part of a larger follow-up study, we examined the foliage of Poliomintha incana using scanning electron microscopy (SEM), to evaluate the possibility that this species may produce foliar salt glands. Foliage samples were collected, rinsed with tap water, and preserved in isopropyl alcohol for transport to the lab. These preserved samples were prepared for SEM analysis of external and internal foliar features. We found three morphologically distinct surface features, including trichomes, and apparent multicellular salt bladders. To our knowledge, this is the first documentation of salt bladders in this species. This research project provides insights into the physiology of plant tolerance of excess Ca, and the physiological and ecological processes that occur in the unique ecosystems present at White Sands National Monument.


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1 - Berry College, Biology, P.O. Box 490430, Mount Berry, GA, 30149, USA
2 - Biology, 1301 E. Main St, Box 60, Murfreesboro, TN, 37132, USA
3 - Middle Tennessee State University, Interdisciplinary Microanalysis and Imaging Center, 1301 E. Main St., Box 378, Murfreesboro, TN, 37132, USA

Keywords:
Calcium
Mineral Nutrition
Plant Physiology
Ecology
Plant Foliage
Toxicity
Poliomintha incana.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Eyrie/Boise Centre
Date: Monday, July 28th, 2014
Time: 5:30 PM
Number: PPS008
Abstract ID:507
Candidate for Awards:None


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