Membrane-bound Ca2+ distribution visualized by chlorotetracycline fluorescence during morphogenesis of soredia in a lichen

Summary In the lichenParmelia caperata (L.) Ach. the distribution pattern of membrane-bound Ca²⁺ is investigated in the symbionts by chlorotetracycline (CTC)-induced fluorescence during the development of propagative structures, the soredia. The results demonstrate that Ca²⁺ accumulation in the alga and the fungus is associated with this morphogenetic process; particularly, polarized hyphal growth involves a tip-to-base Ca²⁺ gradient.CTC fluorescence distribution is coincident with that of cholinesterase (ChE) activity during morphogenesis of soredia. A comparison is suggested with embryonic ChE of animal cells, where developmental events are regulated by a cholinergic mechanism that also modulates Ca²⁺ levels.