A hypothesis concerning callose.

ABSTRACT

Background Concept Certain proteins and the glucose monomer have spacing of their carbonyl oxygen atoms that match the spacing of the oxygen atoms of hexagonal ice. This opens the possibility that a sequence of linked glucose residues may have a sequence of equally spaced carbonyl oxygen atoms. Hypothesis: Callose In plants is a duality consisting of the callose itself and a layer of ordered water whose oxygen atoms are hydrogen bonded to the carbonyl oxygen atoms in the callose. The atomic basis of the hypothesis is that the 1-3 linkage between glucose residues in callose results in equally spaced carbonyl oxygen atoms within and between residues. Properties of Callose/Ordered Water The physical properties of the duality are the properties of callose itself 1) it is immobile, 2) it can be created and dissolved, 3) it can exist at a submicrometer to micrometers space scale. The electrical properties of ordered water in a botanical platform are not known at the present time. They can be derived only from limited data in non biological platforms and inferences from the electrical properties of ice. These properties are 1) proton movement is governed by the Grotthuss mechanism, 2) there is insignificant movement of non-protonic ions and larger molecules through the ordered water, 3) proton movement is isotropic. Proposed Functionality of Callose/Ordered Water Known locations of callose were examined theoretically to determine the functionality of a callose/ordered water duality. These locations were sieve plate pores, plasmodesmata and pollen tubes, stomatal guard cells, companion cell/sieve tube complex and micro and megasporocytes. Protonic Circuits In a botanical context, protonic circuits at a single cell and supracellular level take the form of a proton microloop wherein callose/ordered water is one component in the loop. These circuits use both the enhanced proton mobility and the ion blocking ability of ordered water.