Photograph by Campus Photographer Herb Weitman

The Gladys Levis Allen
Laboratory of Plant Sensory Physiology

Personal Lab Page of Barbara G. Pickard, Professor Emerita
Gladys Levis Allen, Patron Saint of plant sensory biology and mechano biology.
Photograph by Campus Photographer Herb Weitman
The namesake of The Gladys Levis Allen Laboratory of Plant Sensory Physiology is a Washington University alumna, a long-term board member and donor, and the Patron Saint of Plant Electrobiology and Mechanobiology at Washington University. Barbara Pickard is deeply honored that her research program is associated with the memory of Gladys, and notes that interest in the field of study so enthusiastically supported by Gladys is now additionally represented by other labs in the Biology Department. The Pickard lab has a broad range of historical and present interests, all involving how plants sense and respond to stimuli of chemical, electrical and mechanical nature.

Experiments currently underway and manuscripts in preparation deal with:

  1. The role of abscisic acid in gravitropism of maize roots.
  2. A molecular model for gravitropic reception by roots.
  3. Electrical responses to the hormones PIFF and systemin
  4. The cellular basis of whorl and spiral phyllotaxis at the shoot apex.
  5. The biophysical basis of phyllotaxis.
  6. A major structural system at the plant periphery with roles in responses to drought, illumination regime, and mechanical stress.
  7. A biography of Gladys Levis Allen, Inspiration to the Washington University Community.

Collaboration with other scientists is critical for such studies, which involve interaction between many fields of study and many kinds of new instrumentation:

  1. Clifford E. LaMotte, Professor Emeritus at the University of Iowa and Visiting Professor at Washington University, is active in gravitropic studies and is currently comparing abscisic acid levels and influences during modulation of gravitropic response and gravitropic stimulation per se.
  2. Jeffrey F. Harper, Professor at the University of Nevada at Reno, and David W. Ehrhardt, Professor at Stanford and Staff Member at the Carnegie Institution of Plant Biology, interact in all studies requiring high resolution imaging (in particular, spinning disc confocal microscopy) and molecular genetics.
  3. Barbara Abraham-Shrauner, a physicist who is Senior Professor in the Green Department of Eletrical and Systems Engineering at Washington University, provides novel insights into the biophysics of plant morphogenesis.
  4. Guy M. Genin, Associate Professor in the Department of Mechanical and Materials Science, collaborates in current biomechanical and bioelectrical studies, bringing mechanical analysis and new predictive capabilities to the assessment of activities at the plant cell periphery. With his many close collaborators he also brings access to a variety of advanced technologies for examining microstructure at the plant cell periphery.

Students and postdoctoral research associates will now be officially mentored by academically active collaborators in the several departments, owing to the Pickard retirement from formal duties; inquiries about upcoming opportunities may however be addressed to her.

Publications

1. Gillespie, B., Briggs, W.R. 1961. Mediation of geotropic response by lateral transport of auxin. Plant Physiol. 36: 364-368.

2. Gillespie, B., Thimann, KV. 1961. The lateral transport of indoleacetic acid-Cl4 in geotropism. Experientia 17: 126-129.

3. Gillespie, B., Thimann, KV. 1963. Transport and distribution of auxin during tropistic response. I. The lateral migration of auxin in geotropism. Plant Physiol. 38: 214-225.

4. Pickard, B.G., Thimann, KV. 1964. Transport and distribution of auxin during tropistic response. II. The lateral migration of auxin in phototropism of coleoptiles. Plant Physiol. 39: 342-350.

5. Pickard, B.G., Thimann, KV. 1966. Geotropic response of wheat coleoptiles in absence of amyloplast starch. J. Gen. Physiology 49: 1065-1086.

6. Pickard, B.G. 1966. Preface to The Power pf Movement in Plants by Charles Darwin. Reprint by Da Capo Press, New York.

7. Pickard, B.G., with participation by Dutson, K, Harrison, V., Donegan, E. 1969. Second positive phototropic response patterns of the oat coleoptile. Planta 88:1-33.

8. Pickard, B.G. 1969. Comparison of calcium and lanthanon ions in the Avena coleoptile growth test. Planta 91: 314-320.

9. Pickard, B.G. 1971. Analysis of the significance of geotonic data for theories of georeception. In: Gravitv and the Organism, pp. 89-96, Gordon, S.A., Cohen, M.J., eds. University of Chicago Press, Chicago - London.

10. Pickard, B.G. 1971. Influence of previous temperature on stomatal response to osmotica. Experientia 27: 594-595.

11. Pickard, B.G. 1971. Action potentials resulting from mechanical stimulation of pea epicotyls. Planta 97: 106-115.

12. Pickard, B.G. 1972. Spontaneous electrical activity in Ipomoea, Pisum, and Xanthium. Planta 102: 91-114.

13. Williams, S.E., Pickard, B.G. 1972. Receptor potentials and action potentials in Drosera tentacles. Planta 103: 193-221.

14. Williams, S.E., Pickard, B.G. 1972. Properties of action potentials in Drosera tentacles. Planta 103: 222-240.

15. Fuller, F.B., Pickard, B.G. 1972. Spontaneous electrical activity in Coprinus. Zeitschr. fur Pflanzenphysiol. 67: 291-292.

16. Pickard, B.G. 1973. Geotropic response patterns of the Avena coleoptile. I. Dependence on angle and duration of stimulation. Can. J. Bot. 51: 1003-1021.

17. Pickard, B.G. 1973. Geotropic response patterns of the Avena coleoptile. II. Induction at low temperature. Can. J. Bot. 51:1023-1027.

18. Pickard, B.G. 1973. Action potentials in higher plants. Bot. Rev. 39: 172-201.

19. Pickard, B.G. 1974. Electrical signals in higher plants. Die Naturwissenschaften 62: 60-64.

20. Williams, S.E., Pickard, B.G. 1974. Connections and barriers between cells of Drosera tentacles in relation to their electrophysiology. Planta ll6: 1-16.

21. Newman, I.A., Pickard, B.G. 1975. Passive responses resembling action potentials: a device for the classroom. Bioscience 25: 502-503.

22. Van Sambeek, J.W., Pickard, B.G. 1976. Mediation of rapid electrical, metabolic, transpirational, and photosynthetic changes by factors released from wounds. I. Variation potentials and putative action potentials in intact plants. Can. J. Bot. 54: 2642-2650.

23. Van Sambeek, J.W., Pickard, B.G., with participation by Ulbright, C.E. 1976. Mediation of rapid electrical, metabolic, transpirational, and photosynthetic changes by factors released from wounds. II. Mediation of the variation potential by Ricca's factor. Can. J. Bot. 54: 2651-2661.

24. Van Sambeek, J.W., Pickard, B.G. 1976. Mediation of rapid electrical, metabolic, transpirational, and photosynthetic changes by factors released from wounds. III. Measurements of C02 and H20 flux. Can. J. Bot. 54: 2662-2671.

25. Cheeseman, J.M., Pickard, B.G. 1977. Electrical characteristics of cells from leaves of Lycopersicon. Can. J. Bot. 55: 497-510.

26. Cheeseman, J.M., Pickard, B.G. 1977. Depolarization of cell membranes in leaves of Lycopersicon by extract containing Ricca's factor. Can. J. Bot. 55: 511-519.

27. Johnsson, A, Pickard, B.G. 1979. The threshold stimulus for geotropism. Physiol. Plantarum 45: 315-319.

28. Williams, S.E., Pickard, B.G. 1980. The role of action potentials in the control of capture movements of Drosera and Dionaea. Plant Growth Substances 1979. F. Skoog, Ed. Berlin - Heidelberg - NewYork: Springer.

29. Ulbright, C.E., Pickard, B.G., Varner, J.E. 1982. Effects of short chain fatty acids on radicle emergence and root growth in lettuce. Plant, Cell and Environ. 5: 293-301.

30. Ulbright, C.E., Pickard, B.G., Varner, J.E. 1982. Effects of short chain fatty acids on seedlings. Plant, Cell and Environ. 5: 303-307.

31. Pickard, B.G. 1984. Voltage transients elicited by sudden step-up of auxin. Plant, Cell and Environ. 7: 171-178.

32. Pickard, B.G. 1984. Voltage transients elicited by brief chilling. Plant, Cell and Environ. 7: 679-681.

33. Harrison, M., Pickard, B.G. 1984. Burst of ethylene upon horizontal placement of tomato seedlings. Plant Physiol. 75: 1167-1169.

34. Pickard, B.G. 1985. Roles of hormones, protons and calcium in geotropism. In: Hormonal Regulation of Development III, Role of Environmental Factors, Vol. 11 of Encyclopedia of Plant Physiolgy, New Series. R.P. Pharis and D.M. Reid, Ed. pp. 193-281. Berlin - Heidelberg - NewYork: Springer.

35. Pickard, B.G. 1985. Roles of hormones in phototropism. In: Hormonal Regulation of Development III, Role of Environmental Factors, Vol. 11 of Encyclopedia of Plant Physiolgy, New Series. R.P. Pharis and D.M. Reid, Ed. pp. 365-417. Berlin - Heidelberg - New York: Springer.

36. Pickard, B.G. 1985. Early events in geotropism of seedling shoots. Annu. Rev. Plant Physiol. 36: 55-75.

37. Harrison, M.A., Pickard, B.G. 1986. Evaluation of ethylene as a mediator of gravitropism by tomato hypocotyls. Plant Physiol. 80: 592-595.

38. Edwards, K.L., Pickard, B.G. 1987. Detection and transduction of physical stimuli in plants. In: The Cell Surface and Signal Transduction. E. Wagner, H. Greppin, and B. Millet, Eds. pp. 45-66. Berlin - Heidelberg - New York: Springer.

39. Millet, B., Pickard, B.G. 1988. Early wrong-way response occurs in orthogeotropism of maize roots treated with lithium. Physiol. Plantarum 72: 555-539.

40. Guinel, F.C., Pickard, B.G., Varner, J.E., McCully, M.E. 1987. Root cap net in corn. In: Physiology of Cell Expansion During Plant Growth. D.J. Cosgrove and D.P. Knievel, Eds. American Society of Plant Physiolgists, Rockville, Md pp. 280-283.

41. Falke, L.C., Edwards, KL., Pickard, B.G., and Misler, S. 1988. A Stretch-Activated Anion Channel in Tobacco Protoplasts. FEBS Letters 237:141-144.

42. Caspar, T., Somerville, C., Pickard, B.G. 1989. Vigorous geotropism by a starchless mutant of Arabiodopsis: implications for the starch statolith theory of gravity sensing. Planta 177:185-197.

43. Harrison, M.A., Pickard, B.G. 1989. Auxin asymmetry during "wrong-way" gravitropic curvature of tomato hypocotyls. Plant Physiol. 89: 652-657.

44. Pickard, B.G., Ding, J.P. 1992. Gravity sensing by higher plants. Chapter 5 in: Advances in Comparative and Environmental Physiology, Vol. 10. Comparative Aspects of Mechanoreceptor Systems. F. Ito, Ed. Berlin - Heidelberg: Springer pp. 81-110.

45. Badot, P.-M., Ding, J.P., Pickard, B.G. 1992. Mechanically activated ion channels occur in vacuoles of onion bulb scale parenchyma. Comptes Rendus Acad. Sci. Paris ser. III, 315: 437-443.

46. Ding, J.P., Pickard, B.G. 1993. Mechanosensory calcium-selective cation channels in onion epidermis. Plant Journal 3: 83-110.

47. Pont-Lezica, R.F., McNally, J.G., Pickard, B.G. 1993. Wall-to-membrane linkers in onion epidermis. Plant, Cell & Environ. 16: 111-123.

48. Ding, J.P., Pickard, B.G. 1993. Modulation of mechanosensitive calcium channels by temperature. Plant Journal 3: 713-720.

49A. Pickard, B.G., Ding, J.P. 1993. The mechanosensory calcium-selective ion channel: key component of a plasmalemmal control center? Australian Journal of Plant Physiol. 20: 439-459.

49B. Pickard,B.G., Ding, J.P. 1993. The mechanosensory calcium-selective ion channel: key component of a plasmalemmal control center? In: Chemical Signalling in Plants, B.D. Glenn, ed. CSIRO Australia, pp. 439-459.

50. Ding, J.P., Badot, P.-M., Pickard, B.G. 1993. Aluminum and hydrogen ions inhibit a mechanosensory calcium-selective cation channel. Australian Journal of Plant Physiol. 20: 771-778.

51. Pickard, B.G. 1994. Contemplating the plasmalemmal control center. Protoplasma 182: 1-9.

52. Talbott, L., Pickard, B.G. 1994. Differential changes of size distribution of xyloglucan in the cell walls of gravitropically responding Pisum sativum epicotyls. Plant Physiol. 106:755-761.

53. Gens, J. S., Reuzeau, C., Doolittle, K.W., McNally, J.G., Pickard, B.G. 1996. Covisualization by computational optical sectioning microscopy of an array of integrin and associated proteins at the cell membrane of living onion protoplasts. Protoplasma 194: 215-230.

54. Reuzeau, C., Doolittle, K.W., McNally, J.G., Pickard, B.G. 1997. Covisualization in living onion cells of putative integrin, spectrin, actin, intermediate filaments and other proteins at the cell membrane and in an endomembrane sheath. Protoplasma 199: 173-197.

55. Reuzeau, C., McNally, J.G., Pickard, B.G. 1997. The endomembrane sheath: A key structure for understanding the plant cell? Protoplasma 200:1-9.

56. Heinlein, M., Padgett, H. S., Gens, J. S., Pickard, B. G., Casper, S. J., Epel, B. L., Beachy, R.N. 1998. Changing patterns of localization of the tobacco mosaic virus movement protein and replicase to the endoplasmic reticulum and microtubules during infection. Plant Cell 10: 1107-1120.

57. Hong, B., Ichida, A., Wang, Y., Gens, J.S., Pickard, B.G., Harper, J.F. 1999. Identification of a calmodulin-regulated Ca2+-ATPase in the ER. Plant Physiology 119: 1165-1176.

58. Pickard,B.G., Beachy,R.N. 1999. Intercellular connections are developmentally controlled to help move molecules through the plant. Cell 98: 5-8.

59.Gens, J.S.,Fujiki,M.,Pickard,B.G. 2000. Arabinogalactan protein and wall associated kinase in a plasmalemmal reticulum with specialized vertices. Protoplasma, 212:115-134.

60. Dammann, C., Ichida, A., Hong, B., Romanowsky, S., Hrabak, E.M., Harmon, A.C., Pickard, B.G., Harper, J.F. 2003. Subcellular targeting of nine calcium-dependent protein kinase isoforms from Arabidopsis. Plant Physiology (in press).

61. LaMotte, C.E., Pickard, B.G. (2004) Control of gravitropic orientation. I. Nonvertical orientation by primary roots of maize results from decay of competence for orthogravitropic induction. Functional Plant Biology 31, 93-107.

62. LaMotte, C.E., Pickard, B.G. (2004) Control of gravitropic orientation II. Dual receptor model for gravitropism. Functional Plant Biology 31, 109-120.

63. Pickard, B.G., Fujiki, M. (2005: scheduled for publication in October) Ca2+ pulsation in BY-2 cells and evidence for control of mechanosensory Ca2+1selective channels by the plasmalemmal reticulum. Functional Plant Biology.

64. Pickard BG. 2007. Delivering force and amplifying signals in plant mechanosensing. Curr Top Membranes 58:361-392.

65. Pickard, BG 2008. Second extrinsic organizational mechanism for orienting cellulose: modeling a rold for the plasmalemmal reticulum. Protoplasma. PMID 18648731.