Arrest, Senescence and Death of Shoot Apical Stem Cells in Arabidopsis thaliana.

This article focuses on the regulatory mechanisms underlying senescence and programmed cell death (PCD) of shoot apical meristem (SAM) stem cells in flowering plants, which are crucial for plant longevity and crop yield. It outlines the stages of SAM development—proliferation, arrest, and death—highlighting that SAM arrest involves cessation of cell division regulated by the FRUITFULL (FUL)–APETALA2 (AP2) genetic pathway and plant hormones auxin and cytokinin. The review emphasizes the role of reactive oxygen species (ROS), particularly hydrogen peroxide (H2O2), in triggering stem cell death through activation of PCD marker genes such as ORESARA1 (ORE1) and BIFUNCTIONAL NUCLEASE 1 (BFN1). It also discusses the complex interplay of genetic, hormonal, and environmental factors in SAM arrest and death, noting gaps in understanding the precise molecular signals that repress WUSCHEL (WUS) expression and regulate ROS dynamics.