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23. Life-histories of annual plants in a heterogeneous salt marsh environment

Author

Smith, M. H.

Subjects
577, Ecology
Abstract

1. Population differentiation was studied in the halophytic annuals Salicornia and Suaeda maritima at Stiffkey, Norfolk, England. 2. The salt marsh at Stiffkey shows considerable spatial and temporal heterogeneity. The gradient in height across the marsh results in extreme differences in tidal regime and edaphic conditions, while physiographic features such as salt pans, creeks and their associated levees, impose smaller-scale heterogeneity. Salicornia and Suaeda maritima occur throughout the marsh and exhibit striking variations in phenotype associated with particular microhabitats. 3. Monitoring of field populations of these annuals during successive phases of the life cycle showed that morphologically distinct populations differed in aspects of their life-histories. These differences included the control of dormancy and germination, the phenology of growth and development, and fecundity. 4. The genetic and environmental components of these differences were examined in reciprocal transplant experiments of both seed and seedling material and in uniform growth conditions in growth cabinets and in a glasshouse. Survival and many aspects of both vegetative and reproductive performance were measured throughout the life cycle. 5. Much of the variation in natural populations was attributable to differences in plant density. Plant size and fecundity were extremely plastic in their response to density. Phenological features were more stable and structural characters were most stable. Survival was density independent. 6. Environmental differences between sites also had profound effects on growth and survival of the plants. In particular, some aspect of hypersaline edaphic conditions and the presence of perennial vegetation reduced considerably the survival and growth of annual plants. 7. When the density dependent components of performance were removed, and plants from different parts of the marsh were grown under the same environmental conditions, significant differences remained between them in morphology and life-history. This applied both to plants grown on the same site in the field and to those grown under uniform conditions. These differences between populations were likely to be genetic. 8. Three sorts of explanation of the adaptive significance of genetic differences between populations were examined. First, the relative performance and survival of local and foreign populations planted on the same site were examined at all stages of the life cycle. These differences were expressed as relative selection coefficients. The relative success of populations was also measured over an entire generation by comparing numbers of seeds sown with those produced. This gives an estimate of the relative fitness of the local and foreign populations at each site. Second, correlations were examined between life history characteristics of the populations and features of their environment that were likely to act as selective agents. Third, parallel variation was examined between Salicornia and Suaeda maritima populations within the same zone of the marsh. 9. All three of these approaches were adopted to achieve a concensus of information. Each approach suffers different limitations and the interpretation of information obtained from each is discussed critically. 10. Selection usually favoured the survival and growth of local relative to that of foreign populations at all sites and at all stages in the life cycle. The highest selection coefficients were for survival of the lower marsh 1 t" ... upper morsn 1 . popu a lon ln competltlon wlth the~perennla vegetatlon during the growth phase (ca 0.7) and for seed production of upper marsh Suaeda maritima on the lower marsh (ca 0.9). 11. Measures of the intensity of selection at specific stages of the life cycle did not predict accurately the magnitude of selection over an entire generation. All populations planted as seeds on their native site were relatively fitter than foreign populations transplanted to same site. Relative fitness is likely to have been underestimated because the local and foreign populations at each site were not grown in competition with one another. 12. Chromosome numbers were counted in Salicornia plants typical of the populations recognized by their morphologies and life histories. Three tetraploid and three diploid Salicornia populations and three diploid Suaeda maritima populations were identified at stiffkey. 13. The breeding systems and possible genetic structures of Salicornia and Suaeda maritima populations are discussed in relation to population differentiation. salicornia populations appear to be largely inbreeding and consist of many predominantly homozygous lines. occasional outcrossing provides sufficient variability to allow divergence of the populations under selection. population differentiation in Suaeda maritima apears to be maintained by restriction of gene flow between populations by divergence in flowering times, as well as by intense selection.

Published
1985

26. Abstracts

Author

Botero, C. A., Smith, C. E., Holbrook, C., Pinchak, A. C., Johnson, David, Thomson, Dorothy, Mycyk, Taras, Burbridge, M., Mayers, Irvin, Wahba, nR. W. M., Belque, F., Kleiman, S. J., Parker, Steven, Cox, Peter, Holtby, Helen, Roy, Lawrence, St-Amand, Marc A., Murkin, John M., Baird, Donna, Downey, Donal B., Menkis, Alan H., Yang, Fan, Troncy, Éric, Francœur, Martin, Charbonneau, Marc, Vinay, Patrick, Blaise, Gilbert, Splinter, William M., Roberts, David J., Rhine, Elliot J., MacNeill, Helen B., Reid, Craig W., McKay, William PS, Erjavec, Miklavs, McKay, Benjamin W. S., Gregson, Peter H., Blanchet, Travis, Kember, Guy, Lavoie, Josée, Vischoff, Daniel, Cyrenne, Louise, Villeneuve, Edith, Williot, Pierre, Raghupathy, A. K., Haug, R., Punjabi, B., Ditzig, F., Melnik, Howard, Tessler, Michael J., Krasner, L. Jill, Corda, David M., Solanki, Kal, Layon, A. Joseph, Gallagher, T. James, Stoltzfus, Daniel P., Rabuka, Shannon L., Moote, Carol A., Chen, Robert J. B., Yee, Doreen A., Harrington, Ellen, Orser, Beverley A., Giffin, D. Mitch, Gow, Kenneth W., Phang, P. Terry, Walley, Keith R., Warriner, C. Brian, Cohen, Matthew H., Klahsen, Andrew J., O’Reilly, Deirdre, McBride, John, Ballantyne, Margaret, Goranson, Blair D., Lang, Scott, Dust, William N., McKerrell, Jeff, Martin, Guy, Martin, René, Martin, Daniel, Valet, Philippe, Tétrault, Jean-Pierre, Dagenais, Caroline, Pirlet, Martine, Dansereau, Dominique, D’Orléans-Justes, Pedro, Jankowska, Agnès, Veillette, Yves, Mathieson, Angela L., Intrater, Howard, Cruickshank, Lionel, Duke, P. C., Ong, B. Y., Woo, Vincent, Schimnowski, Donna, Trosky, Sharon, Dalton, Linda, Zabani, Ibrahim, Chilvers, Colin R., Vaghadia, Himat, Merrick, Pamela M., Kashkari, Ibrahim, Al-Oufi, Hossam, Jolly, D., Finucane, B. T., Weyland, Wolfgang, Fritz, Ulrich, Landmann, Heike, Schumacher, Ingrid, English, Michael, Kettler, Dietrich, Duffy, Catherine M., Manninen, Pirjo H., Chung, Frances, Sundar, Shanthini, Lobato, Emilio B., Florete, Orlando, Paige, Glenn B., Daloze, Thierry, Chartrand, Daniel A., St-Laurent, Denis, Fox, Gordon S., Rice, Murray L., Doyle, D. John, Volgyesi, George A., Fisher, Joseph A., Slutsky, Arthur, Salazkin, Igor, Brown, Karen A., Kulkarni, Pradeep, Johnson, David, Cujec, Bibiana, McCuaig, Randy, Hurst, Tom, Antecol, David, Bellemare, François, Couture, Jacques, Marchand, Manon, McNeil, Peter, Hung, Orlando, Ho-Tai, Lily M., Devitt, J. Hugh, Noel, Alva G., O’Donnell, Michael P., Greenhow, Robert J., Cervenko, Frank W., Milne, Brian, Peterson, Mark D., Thomson, Ian R., Hudson, Robert J., Rosenbloom, Morley, Moon, Michael, Sareen, Jitender, Bingham, H. Locke, Backman, Steven B., Stein, Reuben D., Fox, Gordon S., Polosa, C., Tessler, Michael, Spadafora, Salvatore M., Fuller, John G., Kim, Lisa, Karkouti, Keyvan, Rose, D. Keith, Ferris, Lorraine E., Rose, DK, Cohen, MM, Ralley, F. E., DeVarennes, B., Robitaille, M., Searle, Norman, Martineau, Raymond, Conzen, Peter, Al-Hasani, A., Ebert, Tom, Muzi, Michael, Hardy, Jean-François, Bélisle, Sylvain, Couturier, André, Robitaille, Danielle, Roy, Micheline, Gagnon, Lyne, Avraamides, Elisabeth J., Murkin, John M., Dryden, P. J., O’Connor, J. P., Jamieson, W. R. E., Reid, I., Ansley, D., Sadeghi, H., Burr, L. H., Munro, A. I., Merrick, P. M., Benaroia, Mark, Baker, Andrew, Mazer, C. David, Errett, Lee, Frenette, Luc, Cox, Jerry, Kerns, Donna, Pearce, Steve, Mark, David, McDonagh, Paul, DeLlma, Lulz, Nathan, Howard, Dupuls, Jean-Yves, Wynands, J.Earl, Moudgil, G. C., Johnson, J. G., Moudgil, G. M., Hall, Richard I., MacLaren, Connie, Ali, M. J., Ballantyne, M., Norris, D., Beed, Stephen D., Menard, Eugene A., Noel, Leon P., Bonn, Gary G., Clarke, William, Gould, H. Marion, Hall, Leslie E., Bernard, Philippe, Bass, Juan, Reid, Craig W., Kearney, Ramona A., Mack, Cheryl A., Entwistle, Lucy M., Bevan, Joan C., Macnab, Andrew J., Veall, Guy, Marsland, Colin, Ries, Craig R., Hamid, Shahnaz K., Selby, Ian R., Sikich, Nancy, Splinter, William M., Hsu, Elizabeth, McCarthy, Patricia, Yang, Ching-Yue, Wu, Wun-Chin, Huang, Jiunn-Jye, Chen, Shyu-Yin, Luk, Hsiang-Ning, Chai, Chok-Yung, Lafreniere, Gina K., Brunet, Donald G., Parlow, Joel L., El-Beheiry, Hossam, Ouanounou, Aviv, Morris, Mary, Carlen, Peter, Morgan, Pamela J., Chapados, Roger, Gauthier, Marlene, Knox, John W. D., LeLorier, Jacques, Lin, Roddy, Rose, Keith, Garvey, Bernadette, McBrobm, Robert, McAdam, L. C., MacDonald, J. F., Orser, B. A., koutsoukos, Georgios, Belo, Susan, Chin, Christopher A., O’Hare, Brendan, Lerman, Jerrold, Endo, Junko, Schwartz, Arthur E., Minanov, Oktavijan, Stone, J. Gilbert, Adams, David C., Sandhu, Aqeel A., Pearson, Mark E., Young, William L., Michler, Robert E., Cutz, Ernest, Kurrek, Matt M., Cohen, Marsha M., Fish, Kevin, Fish, Pamela, Murphy, Patricia, Fung, Donald, Noel, Alva, Szalai, John-Paul, Robicsek, Ari, Rucker, Joshua, Kruger, Joshua, Slutsky, Mark, Sommer, Leeor, Silverman, Jeff, Dickstein, Jodi, Naik, Viren, Hemphill, Douglas J., Kurian, Regina, Jeejeebhoy, Khursheed N., Alahdal, Osama A., Badner, N. H., Komar, W. E., Bhandari, R., Craen, R., Cuillerier, D., Dobkowski, W. B., Smith, M. H., Vannelli, A. N., Bourne, R. B., Rorabeck, C. H., Doyle, J. A., Corvo, Antoinette, Wahba, Richard M., Scheffer, Nathalie, Tsang, John Y. C., Brush, Brad A., N’Guyen, N. Q., Orain, C., Tougui, S., Lavenac, G., Milon, D., Ritchie, Ewan D., Tong, Doris, Norris, Andrew, Miniaci, Anthony, Vairavanathan, Santhira D., FitzPatrick, Timothy, Stafford-Smith, Mark, Kardash, Ken, Trihas, Toula, Kleiman, Simcha J., Rossignol, Michel, Bérard, Dominique, Martel, Brent, Tétrault, J. P., Lunt, Peter G., Coombs, Dennis W., Halpern, Stephen, Peter, Elizabeth A., Janssen, Patricia, Mahy, Jill, Douglas, M. Joanne, Grange, Caroline S., Adams, Timothy J., Wadsworth, Louis, Muir, Holly, Shukla, Romesh, Writer, Desmond, McLaren, Richard, Liston, Robert, Paetkau, Don, Ong, Bill Y., Segstro, Ron, Littleford, Judy, Hurtado, Cristina, Krishnathas, Ananthan, Lannes, Marcelo, Fortier, Joanne, Su, Jun, Jeganathan, Rubini, and Vaillancourt, Suzanne

Published
1996
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30. Abstracts

Author

Mutch, W. A. C., White, I. W. C., Donen, N., Thomson, I. R., Rosenbloom, M., Cheang, M., West, M., Bryson, Greg, Mundi, Christina, Dupuis, Jean-Yves, Bourke, Michael, McDonagh, Paul, Curran, Michael, Kitts, John, Wynands, J. Earl, Carr, Alison S., Hartley, Elizabeth J., Holtby, Helen M., Cox, Peter, Macpherson, Bruce A., Baker, James E., Baker, Andrew J., Mazer, C. David, Peniston, C., David, T., Cheng, D. C. H., Karski, J., Asokumar, B., Carroll, J., Nierenberg, H., Roger, S., Sandier, A. N., Tong, J., Feindel, C. M., Boylan, J. F., Teasdale, S. J., Boylan, J., Harley, P., Froelich, Jennifer E., Archer, David P., Ewen, Alastair, Samanani, Naaznin, Roth, Sheldon H., Hall, Richard I., Neumeister, Michael, Dawe, Gwen, Cody, Cathy, O’Brien, Randy, Shields-Thomson, Jan, LeDez, Kenneth M., Penney, Catherine, Snedden, Walter, Tucker, John, Fauvel, Nicolas, Glavinovic, Mladen, Donati, François, Backman, S. B., Stein, R. D., Polosa, C., Abdallah, C., Gal, S., Clark, A. John, Doig, George A., Gondocz, Tunde, Peter, E. A., Lopez, A., Mathieu, A., Couture, Pierre, Boudreault, Daniel, Derouin, Marc, Allard, Martin, Blaise, Gilbert, Girard, Dominique, Knill, Richard L., Novick, Teresa, Vandervoort, Margaret K., Chung, Frances, Paramanathar, Shantha, Parikh, Smita, Cruise, Charles, Michaloliakou, Christina, Dusek, Brenda, Rose, D. K., Cohen, M. M., DeBoer, D., Shorten, George, Cutz, Earnest, Lerman, Jerrold, Dolovich, Myrna, Crosby, Edward T., Cirone, Robert, Reid, Dennis, Lind, Joanne, Armstrong, Melanie, Doyle, Wanda, Halpern, S., Glanc, P., Myhr, T., Ryan, M -L., Fong, K., Amankwah, K., Ohlsson, A., Preston, R., Petras, Andor, Jacka, Michael J., Milne, Brian, Nakatsu, Kanji, Pancham, S., Smith, Graeme, Duggal, Kush N., Douglas, M. Joanne, Merrick, Pamela M., Blew, Philip, Miller, Donald, Martineau, Raymond, Hull, Kathryn, Baron, C. M., Kowalskl, S., Greengrass, R., Horan, T., Unruh, H., Baron, C. L., Cruchley, Patricia M., Nakajima, K., Sugiura, Y., Goto, Y., Takakura, K., Harada, J., Lee, Robert M. K. W., Fargas-Babjak, Angelica M., Ni, Jin, Werstiuk, Eva S., Woo, Joseph, Morison, David H., McHugh, Michael D., Pappius, Hanna M., Ishihara, Hironori, Shimodate, Yuki, Koh, Hiroaki, Matsuki, Akitomo, Mclntyre, John W. R., Bergeron, Pierre, DeLima, Lulz G. R., Dupuls, Jean-Yves, Enns, James, Murkin, J. M., McKenzie, F. N., White, S., Shannon, N. A., Dobkowski, Wojciech B., Kutt, Judy L., Mezon, Bernard J., Grant, David R., Wall, William J., Doblar, Dennis D., Lim, Yong C., Frenette, Luc, Ronderos, Jaime R., Poplawski, Steve, Ranjan, Dinesh, Dubé, L., Obbergh, L. Van, Francoeur, M., Blouin, C., Carrier, R., Doblar, D., Ronderos, J., Singer, D., Cox, J., Gosdin, B., Boatwright, M., Smith, Charles E., Rovner, Aleksandr, Botero, Carlos, Holbrook, Curt, Patel, Nileshkumar, Pinchak, Alfred, Pinchak, Alfred C., Kao, Yin James, Thio, Andrew, Barker, Steven J., Sullivan, Patrick, Posner, Matthew, Cole, C. William, Lindsay, Patty, Langevin, Paul B., Gulig, Paul A., Gravenstein, N., Wong, David T., Gomez, Manuel, McGuire, Glenn P., Byrick, Robert J., Sharma, Shared K., Carmicheal, Frederick J., Montanera, Walter J., Sharma, Sharad, Yee, D. A., Naser, Basem I., Bryson, G. L., Kitts, J. B., Miller, D. R., Martineau, R. J., Curran, M. J., Bragg, P. R., Karski, Jacek M., Cheng, Davy, Bailey, Kevin, Levytam, S., Arellano, R., Katz, J., Doyle, J., Sosis, Mitchel B., Blazek, William, Plourde, G., Malik, A., Peddle, Tammy, Au, James, Sloan, Jeffrey, Cleland, Mark, Hancock, Donald E., Patel, Nilesh, Costello, Frank, Patterson, Louise, Yamashita, Masao, Kondo, Tsukasa, Graham, M. R., Thiessen, D., Vener, David F., Long, Thomas, Marion, S., Steward, D. J., Braverman, Berton, Levine, Mark, Yentis, Steve, Bachman, Catherine R., Kopelow, Murray, McNeill, Ann, Graham, R., Froese, Norbert, Patel, Leena, Reimer, Heinz, Swartz, Jo, Ullyot, Suzanne, Wong, Harley, Markakis, Maria A., Siklch, Nancy, Goranson, Blair D., Lang, Scott A., Stockwell, Martin J., Cujec, Bibiana, Yip, Raymond W., Southeriand, Lucy C., Vet, Tanya Duke B., Gollagher, Jeisane M., Crone, Lesley-Ann, Ferguson, James G., Litwin, Demetrius, Bertlik, Maria, Orser, Beverley A., Yang, Lu-Wang, MacDonald, John F., Morris, Gary F., Gore-Hickman, Wendy L., Zamora, J. E., Rosaeg, O. P., Lindsay, M. P., Crossan, M. L., Pattee, Carol, Adams, Michael, Koller, John P., Lavoie, Guy J., Rigal, Wynn M., Taylor, Dylan A., Grace, Michael G., Flnegan, Barry A., Hawkes, Christopher, Hopkins, Harry, Tierney, Michael, Drover, David R., Whatley, Gordon, Knox, J. W. Donald, Rausa, Jarmila, El-Beheiry, Hossam, Seegobin, Ronald, Hirst, Georgia C., Dust, William N., Cassidy, J. David, Boisvert, D., Braden, H., Halperin, M. L., Cheema-Dhadli, S., McKnight, D. J., Singer, W., Elwood, Thomas, Huchcroft, Shirley, MacAdams, Charles, Farran, R. Peter, Goresky, Gerald, LaLande, Phillip, Lacroix, Gilles, Lessard, Martin, Trépanier, Claude, van Vlymen, Janet M., Parlow, Joel L., Ibebunjo, Chikwendu, Morscher, Arnold H., Gordon, Gregory J., Grocott, H. P., Belo, Susan E., Koutsoukos, Georgios, Belo, Susan, Smith, David, Henderson, Sarah, Gelb, Adriene, Kantor, G., Badner, N. H., Komar, W. E., Bhandari, R., Cuillerier, D., Dobkowski, W., Smith, M. H., Vannelli, A. N., Wharton, Sean, Tierney, Mike, Redmond, E., Reddy, E., Gray, A., Flynn, J., Bourne, R. B., Rorabeck, C. H., MacDonald, S. J., Doyle, J. A., Newton, Peter T., Moote, Carol A., Joiner, R., Glynn, M. F. X., Zulys, Vytas, Hennessy, M., Winton, T., Demajo, W., McKay, William P. S., Gregson, Peter H., McKay, Benjamin W. S., Militzer, Julio, Hollebone, Eric, Yee, Raymond, Klein, George, Garnett, R. L., Conway, J., Ralley, F. E., Robbins, G. R., Brown, James E., Frei, J. V., Podufal, Edward, Snow, Norman J., Chavez, Altagracia M., Kramer, Richard P., Mickle, D., Tweed, William A., Shrestha, Bisharad M., Basnyat, Narendra B., Lekhak, Bhawan D., O’Leary, Susan D., Maryniak, J. K., Tucker, John H., Guest, Cameron B., Mullen, J. Brendan, Kay, J. Colin, Wigglesworth, Dan F., Goodarzi, Mashallah, Shier, Nicte Ha, Ogden, John A., Hung, O. R., Pytka, S., Murphy, M. F., Martin, B., and Stewart, R. D.

Published
1994
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36. Optical system analysis for the ground based EXVM

Author

Hillman, L. W, Chipman, R. A, and Smith, M. H

Subjects
Optics
Abstract

The MSFC's Experimental Vector Magnetograph (EXVM) is an instrument that observes a 4.4 x 8.8 arcmin field of the sun. The transverse and longitudinal components of the surface magnetic field and the line-of-sight velocities of the photospheric gases can be determined from polarimetric and spectral analysis of the 525.02 nm absorption line of Fe 1. The EXVM has been breadboarded and tested in the laboratory. The optics of the EXVM were tested with a point-diffraction (Smartt) interferometer. The 12 inch Cassegrain telescope was found to have 0.20 waves RMS (at 525.02 nm) of aberration. The post-telescope relay optics were nearly diffraction limited on-axis and had about one wave of primary coma as the predominant aberration at full-field. From theoretical modulation transfer function (MTF) curves of known aberrations, it was concluded that the EXVM should attain a maximum spatial resolution of about 0.5 arcseconds. A resolution test target indicated maximum angular resolutions better than 0.6 arcsec on-axis and 0.7 arcsec at full-field-of-view. A 2D inch heliostat (sun-tracking mirror) was used to direct sunlight into the lab and into the EXVM. Solar images obtained were limited by atmospheric seeing effects. During brief moments of good seeing, angular resolutions of about 1 arcsecond were realized with the EXVM.

Published
1993

37. Infrared imaging - A validation technique for computational fluid dynamics codes used in STOVL applications

Author

Hardman, R. R, Mahan, J. R, Smith, M. H, Gelhausen, P. A, and Van Dalsem, W. R

Subjects
Instrumentation And Photography
Abstract

The need for a validation technique for computational fluid dynamics (CFD) codes in STOVL applications has led to research efforts to apply infrared thermal imaging techniques to visualize gaseous flow fields. Specifically, a heated, free-jet test facility was constructed. The gaseous flow field of the jet exhaust was characterized using an infrared imaging technique in the 2 to 5.6 micron wavelength band as well as conventional pitot tube and thermocouple methods. These infrared images are compared to computer-generated images using the equations of radiative exchange based on the temperature distribution in the jet exhaust measured with the thermocouple traverses. Temperature and velocity measurement techniques, infrared imaging, and the computer model of the infrared imaging technique are presented and discussed. From the study, it is concluded that infrared imaging techniques coupled with the radiative exchange equations applied to CFD models are a valid method to qualitatively verify CFD codes used in STOVL applications.

Published
1991

40. Production of aerosol at the ocean surface

Author

Smith, M. H., Park, P. M., Hill, M. K., Consterdine, I. E., Latham, J., Araki, H., editor, Ehlers, J., editor, Hepp, K., editor, Kippenhahn, R., editor, Weidenmüller, H. A., editor, Wess, J., editor, Zittartz, J., editor, Beiglöck, W., editor, Wagner, Paul E., editor, and Vali, Gabor, editor

Published
1988
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43. Nematic–lamellar tricritical behavior and structure of the lamellar phase in the ammonium pentadecafluorooctanoate (APFO)/water system.

Author

Boden, N., Clements, J., Jolley, K. W., Parker, D., and Smith, M. H.

Subjects
AMMONIUM compounds, SPECTRUM analysis
Abstract

2H NMR spectroscopy has been used to map a high-resolution (±0.04 K) phase diagram for the ammonium pentadecafluorooctanoate(APFO)/heavy water system. It is qualitatively similar to that for the CsPFO/heavy water system. In particular, it exhibits a discotic micellar nematic phase N+D intermediate to an isotropic micellar solution phase I and a lamellar phase for weight fractions of APFO between 0.395 ([lowercase_phi_synonym]=0.278) and 0.589 ([lowercase_phi_synonym]=0.455) and temperatures between 292.10 and 338.10 K. The N+D to lamellar transition crosses over from second to first order behavior at a tricritical point similar to the superfluid transition in 3He/4He mixtures. X-ray scattering experiments shows there to be no dramatic change in the structure of the micelle at the I to N+D and the N+D to lamellar transitions. Nematic order parameters (orientational order parameters of the discoidal micelles) have been calculated from electrical conductivity measurements. Their variation with temperature in the nematic phase and across the nematic to lamellar transition are qualitatively consistent with the behavior expected for thermotropic calamitic liquid crystals undergoing an isotropic to nematic to smectic-A sequence of transitions.It is, therefore, concluded that the transition from the N+D to the lamellar phase solely involves the propagation of long range positional ordering of the discoidal micelles into planes along the nematic director, that is, the lamellar phase is a discotic lamellar phase LD. This result reinforces previous claims about the structure of the lamellar phase of the CsPFO system as opposed to the alternative scenario of a classical lamellar phase in which the bilayers are perforated by microscopic defects. This conclusion is supported by measurements of 2H quadrupole splittings of heavy water. Similar measurements for deuterated ammonium ions show a preference for counterion binding to sites of lowest surface... [ABSTRACT FROM AUTHOR]

Published
1990
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