Contact Information
Phone:(808) 623-0145
Email: dave@hawaii.edu

Link to Laboratory Site

Link to Course Pages

• Cycad Root Nodulation & Symbiosis
• Leaf Anatomy
• Ethnobotanical Anatomy
• Lettuce as an Model Experimental System for K-16

Statement
My overall orientation and training lie in the realm of plant developmental anatomy and morphology. I am starting a major effort to resume my studies of Cyacd root nodulation and symbiosis. There are many fundamental aspects of this unique phenomenon that are unexplored. I plan to combine various types of microtomy and in vitro methods to explore the establishment and development of the symbiotic relationship between Cycad roots and Cyanobacteria. This will be my major research effort in the coming years. I have been involved in several leaf anatomy projects at the University of Hawaii, and I maintain an interest in this area as it applies to environmental adaptations.  I have applied anatomical methods to determine the identity of plants used to make various Hawaiian artifacts and this is an extremely fertile area for future research.  I have developed a wide array of experiments that can be done with lettuce seeds and seedlings. I am using these in local educational research and expect that I can develop this along the lines of the C-Fern and Wisconsin Fast Plants.

Selected Publications

• Borthakur D, Soedarjo, Fox PM, and Webb D.T. (2003) The mid genes of Rhizobium sp. strain TAL1145 are required for degradation of mimosine into 3-hydroxy-4-pyridone and are inducible by mimosine. Microbiology 149: 537-546 .
  
  
• L. W. Neuteboom, W. Y. Kunimitsu, D. Webb, D. A. Christopher. (2002) Characterization and tissue-regulated expression of genes involved in pineapple (Ananas comosus L.) root development. Plant Science, 165:1021-1035 .
  
  
• Matsumoto, T.K., A. R. Kuehnle & D. T. Webb. (1998) Zygotic Embryogenesis in Anthurium (Araceae), Amer. J. Bot. 85: 1560-1568.
  
  
• Tanuwidjaja, C., D. T. Webb & Y. Sagawa (1998). Micropropagation of 'Akia (Wilkstroemia uva-ursi A. Gray). Plant Cell, Tissue, Organ Culture, 53: 85-90.
  
  
• Kitayama, K., R. Pattison, S. Cordell, D. Webb and D. Mueller-Dombois (1997). Ecological and genetic implications of foliar polymorphism in Metrosideros polymorpha Gaus. (Myrtaceae) in a habitat matrix on Mauna Loa , Hawaii . Annals of Botany, 80: 491-497.
  
  
• Cordell, S., G. Goldstein, D. Mueller-Dombois, D. Webb and P. V. Vitousek (1998). Physiological and morphological variation in Metrosideros polymorpha, a dominant Hawaiian tree species, along an altitudinal gradient: the role of phenotypic plasticity. Oecologia, 113: 188-196.
  
  
• Parveen, N., D.T. Webb and D. Borthakur. (1997) The symbiotic phenotypes of exoploysaccharide-defective mutants of Rhizobium sp. strain TAL1145 do not differ on determinate- and indeterminate-nodulating tree legumes. Microbiology . 143: 1959-1967.
  
  
• Parveen, N., D.T. Webb and D. Borthakur. (1997). Leucaena leucocephala nodules formed by a surface polysaccharide mutant of Rhizobium sp. Strain TAL1145 are delayed in bacteroid development and nitrogen fixation. Molecular Plant Microbial Interaction. 9:364-372.
  
  
• Chen, W-Q., D.E. Gardner and D. T. Webb. (1996) Biology and life cycle of Atelocauda koae an unusual demicyclic rust. Mycoscience 37: 91-98.
  
  
• Matsumoto, T., D.T. Webb and A.R. Kuehnle. (1995) Microtechnique Improvement for Light Microscopic Observations of Anthurium (Araceae) Floral Structure. Biotechnic & Histochemistry. 70: 205-210.
  
  
• Zimmermann, U., J. J. Zhu, F. Meinzer, G. Goldstein, H. Schneider, G. Zimmermann, R. Benkert, F. Thurmer, D. Webb and A. Hasse. (1994). High molecular weight organic compounds in the xylem sap of mangroves: Implications for long-distance transport. Botanica Acta 107: 187-270.
  
  
• Flinn, B. S., Roberts, D. R., Webb D. T. and Sutton B. C. S. (1991) Storage Protein Changes During Zygotic Embryogenesis in White Spruce [Picea glauca], Tree Physiol., 8: 71-81 .
  
  
• Roberts, D. R., Flinn, B. S., Webb, D.T., Webster F. W., and Sutton B. C. S. (1990) Abscisic Acid and Indole-3-Butyric Acid Regulation of Maturation and Accumulation of Storage Proteins in Somatic Embryos of Interior Spruce, Physiol. Plant., 78: 355-360 .
  
  
• Flinn, B. S., Webb, D.T., and Newcomb, W. (1989) Morphomertic Analysis of Reserve Substances and Ultrastructural Changes During Caulogenic Determination and Loss of Competence of Eastern White Pine [Pinus strobes L.] Cotyledons In Vitro, Can. J. Bot., 67: 779-789 .
  
  
• Webb, D.T., Webster, F., Flinn, B.S., Roberts, D.R., and Ellis, D.E. (1989) Factors Influencing the Induction of Embryogenic and Caulogenic Callus from Embryos of Picea glauca and P. engelmanii, Can. J. For. Res., 19: 1303-1308 .
  
  
• Kurz, M.L., Webb, D.T., and Vidaver, W.E. (1989) Micropropagation of Yellow Cedar (Chamaecyparis nootkatensis) from Cultured Embryos, Plant Cell, Tissue and Organ Culture, 18: 297-312 .
  
  
• Flinn, B.S., Webb, D.T., and Newcomb, W.N. (1988) The Role of Cell Clusters and Promeristemoids in Determination and Competence for Caulogenesis by Pinus strobus Cotyledons In Vitro, Can. J. Bot., 66: 1556-1565 .
  
  
• Webb, D.T., Flinn, B.S., and Georgis, W. (1988) Micropropagation of Eastern White Pine (Pinus strobus L.), Can. J. For. Res., 18: 1570-1580 .
  
  
• Webb, D.T. and Slone, J.H. (1987) Anatomy of Macrozamia Communis Lateral Roots and Root Nodules, Studied with Light and Scanning Electron Microscopy, Amer. J. Bot., 74: 1625-1634 .
  
  
• Flinn, B.S. and Webb, D.T., In vitro Control of Caulogenesis by Growth Regulators and Media Components with Embryonic Explants of Eastern White Pine (Pinus strobus L.), Can. J. Bot., 64: 1948-1956 (1986).
  
  
• Webb, D.T., Torres, L.D., and Fobert, P. (1984) Interactions of Growth Regulators, Explant Age and Culture Environment Controlling Organogenesis from Lettuce Cotyledons In Vitro, Can. J. Bot., 62: 586-590 .
  
  
• Webb, D.T., Nevarez, M., and DeJesus, S. (1984) Further in vitro Studies of Light-Induced Root Nodulation in the Cycadales, Env. Exp. Bot. 24: 37-44 .
  
  
• Webb, D.T. (1983) Developmental Anatomy of Light-Induced Root Nodulation of Zamia pumila L. Seedlings in Sterile Culture," Amer. J. Bot., 70: 1109-1117 .
  
  
• Webb, D.T. (1983) Nodulation in Light and Dark-Grown Macrozamia communis L. Johnson Seedlings in Sterile Culture, Ann. Bot., 52: 543-547 .
  
  
• Webb, D.T. (1982) Structure and Ultrastructure of Plastids in Light and Dark-grown Zamia floridana DC. Seedling Roots in vitro, New Phytol., 91: 721-726 .
  
  
• Webb, D.T. (1982) Effects of Light on Elongation, Apogeotropism and Nodulation of Zamia pumila L. Seedlings in Sterile Culture," Amer. J. Bot., 69: 298-305 .
  
  
• Webb, D.T. (1982) Importance of Megagametophyte and Cotyledons for Root Growth of Zamia floridana DC. Embryos in vitro, Z. Pflanzenphysiol., 106: 37-42 .
  
  
• Webb, D.T. (1982) Importance of Megagametophyte and Cotyledons for Root Growth of Zamia floridana DC. Embryos in vitro, Z. Pflanzenphysiol., 106: 37-42 .
  
  
• Webb, D.T. (1982) Effects of Light Intensity on Root Growth and Nodulation of Zamia floridana DC. Embryos in Sterile Culture, Phytomorphology, 32: 81-84 .
  
  
• Webb, D.T. (1981) Effects of Light Quality on Root Elongation and Nodulation of Zamia floridana DC. Seedlings in Sterile Culture, Z. Pflanzenphysiol., 104: 253-258 .