Fig. 6.

Hypothetical model of silicon uptake in cucumber. The schematic diagram shows the putative silicon uptake process in cucumber roots. Purple and blue arrows represent the transporter-mediated silicon transport in root cells. The orange boxes represent the plasma membrane of epidermal and cortical cells where CsLsi1 functions as a silicon influx transporter, and the blue box represents the plasma membrane of endodermal cells where CsLsi2 functions as a silicon efflux transporter. The dotted and solid green arrows show the symplasmic (via plasmadesma) and apoplasmic flows, respectively, in the roots.