Title
Programmed cell death during the transition from multicellular structures to globular embryos in barley androgenesis
Author
Maraschin, S.D.F.
Gaussand, G.
Pulido, A.
Olmedilla, A.
Lamers, G.E.M.
Korthout, H.
Spaink, H.P.
Wang, M.
Publication year
2005
Abstract
Androgenesis represents one of the most fascinating examples of cell differentiation in plants. In barley, the conversion of stressed uninucleate microspores into embryo-like structures is highly efficient. One of the bottlenecks in this process is the successful release of embryo-like structures out of the exine wall of microspores. In the present work, morphological and biochemical studies were performed during the transition from multicellular structures to globular embryos. Exine wall rupture and subsequent globular embryo formation were observed only in microspores that divided asymmetrically. Independent divisions of the generative and the vegetative nuclei gave rise to heterogeneous multicellular structures, which were composed of two different cellular domains: small cells with condensed chromatin structure and large cells with normal chromatin structure. During exine wall rupture, the small cells died and their death marked the site of exine wall rupture. Cell death in the small cell domain showed typical features of plant programmed cell death. Chromatin condensation and DNA degradation preceded cell detachment and cytoplasm dismantling, a process that was characterized by the formation of vesicles and vacuoles that contained cytoplasmic material. This morphotype of programmed cell death was accompanied by an increase in the activity of caspase-3-like proteases. The orchestration of such a death program culminated in the elimination of the small generative domain, and further embryogenesis was carried out by the large vegetative domain. To date, this is the first report to show evidence that programmed cell death takes part in the development of microspore-derived embryos. © Springer-Verlag 2005.
Subject
Androgenesis
Barley
Caspase-3 like proteases
Exine wall
Programmed cell death
TUNEL
Cell membranes
Cytology
DNA
Morphology
Plants (botany)
Vegetation
Androgenesis
Cell differentiation
Chromatin condensation
Microspores
Plant cell culture
apoptosis
cell differentiation
cytology
physiology
pollen
prenatal development
Apoptosis
Cell Differentiation
Hordeum
Pollen
Anatomy
Cells
Plants
Protoplasm
Hordeum vulgare subsp. vulgare
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http://resolver.tudelft.nl/uuid:b6d2482a-3755-41c6-ac30-52fb38aeb2db
DOI
https://doi.org/10.1007/s00425-004-1460-x
TNO identifier
238523
ISSN
0032-0935
Source
Planta, 221 (4), 459-470
Document type
article