| Meristem |
Region of the root where cell division occurs, encompassing the stem cell niche with slowly dividing cells as well as the rest of the meristem with rapidly dividing cells. |
| Basal meristem |
Shootward portion of the meristem. |
| Transition zone |
Boundary region between the meristem and elongation zone where cell division ceases and cell elongation sets in. |
| Elongation zone |
Region of the root shootward of the meristem in which no further cell divisions occur and rapid cell elongation occurs. |
| Differentiation zone |
Region of the root shootward of the elongation zone where no further cell elongation occurs and cells fully differentiate. |
| Oscillation zone |
Region of the root in which auxin (response) and gene expression oscillations are observed, overlapping with the basal meristem and the rootward part of the elongation zone. |
| Priming signal |
Initial signal leading toward specification of a small group of pericycle cells to form lateral root founder cells. |
| Prebranch site |
Subset of cells that underwent a priming event, maintain a stable auxin response, and that will later form a lateral root. |
| Priming |
Signaling in a subset of protoxylem cells that, when successful, leads to the formation of prebranch sites in the overlaying pericycle cells. |
| Founder cells |
A subset of pericycle cells, usually at one of the two xylem poles, progressing from prebranch site state toward lateral root primordium development. |
| Initiation |
The initial, asymmetric divisions that demarcate the start of lateral root development. |
