Valve morphogenesis and silicon dynamics in the synchronized culture of Ulnaria danica

Abstract

Formation of diatom siliceous cell walls occurs inside the cells and depends on the availability of silicon from the environment. In the current work we have studied the valve morphogenesis of a freshwater pennate diatom Ulnaria danica in a laboratory culture synchronized by silica starvation and absence of light. Approximate timelines were established for the initiation of valve synthesis and formation of its major components. It was shown that the silicon surge uptake takes place, e.g. silicon concentration in the medium reduces during the first 30 minutes after the addition of silicon to a synchronized culture. During the formation of main valve elements, intracellular silicon pool is lower than it is after the end of synchronization, returning to the original level only 90 minutes after the addition of silica and beginning of the morphogenesis.