INVOLVEMENT OF SODIUM IN A PROCESS OF CELL-DIFFERENTIATION IN PLANTS

Using analytical imaging by secondary ion mass spectrometry, a dramati c increase of the Na/Ca concentration ratio was observed to strictly p arallel the differentiation of the secondary cell walls in herbaceous and woody dicotyledons grown under normal (i.e. not excessively saline ) conditions. Reciprocally, sodium deprivation delayed and specificall y altered secondary-wall differentiation. These findings provide new i nformation concerning the still controversial problem of how wall diff erentiation is controlled in plant cells. More generally, this unexpec ted effect of sodium reveals that the role of inorganic cations in cel l differentiation can be more intricated and diversified than is usual ly assumed.