Nanoscience and Nanotechnology Commons^™

The sieve tubes of the phloem are enigmatic structures. Their role as channels for the distribution of assimilates was established in the 19th century, but their sensitivity to disturbations has hampered the elucidation of their transport mechanisms and its regulation ever since. Ernst Münch's classical monograph of 1930 is generally regarded as the first coherent theory of phloem transport, but the ‘Münchian’ pressure flow mechanism had been discussed already before the turn of the century. Münch's impact rather rested on his simple physical models of the phloem that visualized pressure flow in an intuitive way, and we argue that the …

The forisome is a protein structure of plants which, in low Ca2+ solutions, assumes a crystalline condensed conformation and, at high Ca2+, swells to a dispersed conformation; this transition has been attributed to electrostatic deformation of protein “modules”. Forisomes could become an important smart material if the energy density of transformation approached 1 MJ m−3. Quantitation of the forisome as a charged porous continuum permeated by electrolyte fails by orders of magnitude to achieve this energy density electrostatically. However, condensed → dispersed transitions can be visualized alternatively: (i) an ionic bond near the surface of a forisome crystal dissolves to …