Apoptosis in Plants

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.

The Role of Cytosolic Potassium and pH in the Growth of Barley Roots

“…Under these K ϩ -starved conditions, the seminal root cells may be showing programmed cell death so that specific sink root meristems are removed and K ϩ is made available to supply the emerging adventitious roots. Proof of apoptosis would require the identification of the morphological and biochemical markers (for review, see Harvel and Durzan, 1996) that are associated with this process in the root cells.…”

The Utilization of Soybean Straw. I. Fiber Morphology and Chemical Characteristics

“…Because of the longer sunlight, higher temperature, and sufficient moisture at the time of planting, soybean plants grow rapidly (Hara 1995;Havel and Durzan 1996). As shown in Fig.…”

Metabolic Engineering of Plant Cells in a Space Environment

“…The concept was extended (Durzan and Steward, 1984) to the nl0lecular level and to cycles of nuclear-cytoplasnlic deter111ination. Totipotency was then related to latent apolnictic plasticity with palingenic, cenogenic, and progenic expressions (Durzan, 1996b), and to adaptive programmes in apoptosis (Havel and Durzan, 1996a). Conifer genomes were expressed Inillions of years ago when days were less than 24 hours, and gravitational forces were less than I x g (Nechitailo and Mashinsky, 1993;Dott and Prothero, 1994).…”

“…Conifers were designated of high interest by the National Cancer Institute survey (Barclay and Perdue, 1976) as having significant anticancer activity~Conifers also offer cOlnplications for nletabolic engineering 110t always found in sitnpler and more recently evolved plants such as Arabic/(J!Jsis. Over 200 lnillion years, conifers have coupled the diversification of secondary products with ontogenetic programs for longevity, adaptive plasticity, secondary xylem, and reaction (or cOlnpression wood) in response to gravitational ,lnd mechanical forces well before angiosperms evolved (Havel and Durzan, 1996a).…”