| Abstract: | Apoptosis is a feature of animal cells that explains some aspects of programmed cell death in plants. Differences between plant and animal cell development require that concepts be reexamined to signify how plant cells have evolved the need for cell elimination in the meristematic growth habit, life cycle, and alternation of generations. Central to this theme is the regulation of divisional cycles for mitosis, meiosis, apomeiosis, and their related sexual and asexual reproductive processes. Apoptosis depends on the coordinated expression of genes regulating divisional cycles and apoptotic pathways so that irreversible nuclear and cytoplasmic elimination occurs. Cellular degradation products are salvaged to sustain adaptation, viability, structural function, and ontogeny. The cell wall is usually retained and further differentiated or eliminated. A model of factors predisposing apoptosis and comprising checkpoints in cell divisional cycles is presented for comparisons among plant and animal cells. |
