Philip M. Lintilhac
# Philip M. Lintilhac

Philip Malcolm Lintilhac (born March 12, 1940) is an American botanist and cell biologist, known for his pioneering work in the study of plant developmental biomechanics and for his novel experimental and theoretical approaches to the study of plant tissue architecture, for which he was awarded the Botanical Society of America’s Centennial award in 2006. He is currently a research associate professor at the University of Vermont.

## Career

Early scientific work on the ultrastructure of photosynthetic chloroplasts at the University of California, Berkeley, with Dr. Roderic Park helped resolve an emerging question regarding the nature of the initial “light-harvesting” reactions of photosynthesis by showing that the chlorophyll molecules were tightly bound into the thylakoid membranes of chloroplasts, rather than being dispersed in solution through the liquid stroma. This confirmed the hypothesis that the initial energy-capture reactions of the chlorophyll molecules were accomplished by solid-state energy transfer through a membrane-bund substrate, rather than by solution chemistry (Lintilhac & Park 1966). Working at the Laboratory of Chemical Biodynamics, established by Dr. Melvin Calvin.

Lintilhac and Park combined electron-microscopy with early fluorescence microscopy to show that the characteristic long-wavelength fluorescence of the chlorophyll molecule coincided exclusively with the membrane portion of chloroplast thylakoids, indicating that the active light-harvesting reactions were aligned with the chloroplast thylakoid membranes.

After this early experimental success his interests shifted to the study of the embryological anatomy of the cotton plant (Gossypium hirsutum) where he began a lifelong interest in the biomechanics and biophysics of plant cell and tissue architecture.

In a series of papers published in the American Journal of Botany in 1974, using simple photoelastic models observed in polarized light, he demonstrated that the precise cell wall placements during cell division in actively growing plant tissues are governed by simple stress-mechanical rules. Lintilhac was able to show that cell wall patterning in the immature cotton ovule coincide with the principal stress trajectories generated by growth forces radiating through the embryonic tissues, indicating that cell division itself is directly responsive to mechanical stress fields propagating through meristematic plant tissues. He then applied the same photoelastic methodology to illustrate the fact that many other aspects of plant growth and development are reducible, in principle, to basic physical interactions. This work began to build a general theory of plant growth that ascribes many aspects of structural development to biophysical and biomechanical control systems that supersede and augment the more traditional molecular and genetic control systems that were typically considered to be in control of all plant development (Lintilhac 2014).

Lintilhac obtained patents for related biomechanical research instrumentation, including a sterilizable mechanical forcing-frame for studying the effects of controlled external forces applied to living plant tissues in culture, and a patent describing the first non-destructive method for measuring the internal turgor-pressures of living plant cells. Most recently Lintilhac & Grasso have developed a method for microfluidic encapsulation of individual, living plant cells into microscopic polymer beads, enabling the study of individual plant cells under controlled mechanical conditions.

Lintilhac's work continues to be based on the proposition that the evolution of land plant architecture has been driven, to a great extent, by the ability of plant tissues to interpret and respond to complex mechanical signals that control many aspects of plant morphogenesis, and which are largely responsible for the characteristic patterning of growing plant tissues. Most recently, Lintilhac has proposed the theoretical argument that the initiation of reproductive differentiation in plants can similarly be traced to biomechanical relationships in the early stages of sporangial growth, linking reproductive development in all the land plants to the evolution of the sporangium as a biomechanical device.

Lintilhac's work has come to be known for his novel interpretation of issues that had previously only been approached in terms of molecular signaling and hormonal specificity, regarding them instead as issues that could be resolved in terms of a unifying deterministic theory of plant biomechanics.

## Publications

* Lintilhac, P.M., and Park, R.B. Localization of Chlorophyll in Spinach Chloroplast lamellae by Fluorescence Microscopy. Journal of Cell Biology. 28: (3) 582-585 (1966).
* Lintilhac, P.M., and Jensen W. Differentiation, Organogenesis, and the Tectonics of Cell Wall Orientation. I. Prelinary Observations on the Development of the Ovule in Cotton. Am. J. Bot. 61: (2) 129-134 (1974).
* Lintilhac, P.M. Differentiation, Organogenesis, and the Tectonics of Cell Wall Orientation. II. Separation of Stresses in a Two-dimensional Model. Am. J. Bot. 61: (2) 135-140 (1974).
* Lintilhac, P.M. Differentiation, Organogenesis, and the Tectonics of Cell Wall Orientation. III. Theoretical considerations of cell wall mechanics. Am. J. Bot. 61: (3) 230-237 (1974).
* Lintilhac, P.M., and Vesecky, T. Mechanical Stress and Cell Wall Orientation in Plants. I. Photoelastic derivation of Principal Stresses. With a Discussion of the Concept of Axillarity and the Significance of the “Arcuate Shell Zone”. Am. J. Bot. 67: (10) 1477-1483 (1980).
* Grasso, M. S., and Lintilhac, P. M., Microbead encapsulation of living plant protoplasts: A new tool for the handling of single plant cells. Applications in Plant Sciences 4: (5) 1500140. (2016).
* Wei, C., and Lintilhac, P.M., Loss of stability – a new model for stress relaxation in plant cell walls. Journal of Theoretical Biology 224: (3) 305-312 (2003).
* Wei, C., Lintilhac, L.S., and Lintilhac, P.M. Loss of Stability, pH, and the anisotropic extensibility of Chara cell walls. Planta 223: 1058-1067 (2006).
* Lintilhac, P.M. Toward a theory of cellularity – Speculations on the nature of the living cell. Bioscience 49: (1) 59-68 (1999).
* Lintilhac, P.M., and Vesecky, T.B. Stress-induced alignment of division plane in plant tissues grown in vitro. Nature 307: (5949) 363-364 (1984)
* Wei, C., Lintilhac, P.M. Loss of stability: A new look at the physics of cell wall behavior during plant cell growth. Plant Physiology 145: 763–772, (2007).
* Lintilhac, P.M., Wei, C., Tanguay, J.T., and Outwater, J.O. Ball tomometry: a rapid, nondestructive method for measuring cell turgor pressure in thin-walled plant cells. J Plant growth Regul 19: 90-97 (2000)
* Lintilhac, P.M. The problem of morphogenesis: unscripted biophysical control systems in plants. Protoplasma 251:15-36
* Lintilhac, P.M. Stochasticity and the limits of molecular signaling in plant development. Frontiers in Plant Science 13:01-04 (2022)
* Lintilhac, P.M., Plant cytomechanics and its relationship to the development of form. Cytomechanics, Ed: Bereiter-Hahn, J., Anderson, O.R., and Reif W-E., Springer-Verlag, Berlin (1987).
