|ACTA BIOLOGICA CRACOVIENSIA Series Botanica 47/1: 147-157, 2005
Cellular Accumulation of Protein Bodies and Changes in DNA Ploidy Level During Seed Development of Lathyrus tuberosus L.
Sławomira Knake-Sobkowicz and Kazimierz Marciniak
Department of Plant Anatomy and Embryology, University of Łódź,
ul. Banacha 12/16, 90-237 Łódź, Poland
Received December 1, 2004; revision accepted april 20, 2005
Mitotic activity, changes in nuclear DNA content and accumulation of protein bodies during endosperm and embryo development of Lathyrus tuberosus L. (2C DNA 15.1 ± 0.08 pg) were analyzed. A gradual decrease in mitotic activity of embryo cells was observed during seed development. At the final stages of embryogenesis, mitotic activity was noted only in tip meristems and provascular tissue. The decrease in mitotic activity in endosperm was accompanied by an increase in amitosis frequency. Cytophotometry of nuclear DNA revealed that in endosperm the nuclei underwent six endoreplication rounds, reaching 192C. The C DNA level was much higher at the chalazal pole than at the micropylar pole, where it was only 12C. In the cotyledon the nuclear DNA level reached 64C (five endoreplication rounds), while in the hypocotyl-root axis it increased from 2C to 4C. Cells of all Lathyrus tuberosus embryo organs are involved in the synthesis of storage proteins and their accumulation in the form of protein bodies. This process starts ˜21 days after fertilization (DAF). Cells containing protein bodies are capable of division. The authors characterized the central and basal zones of cotyledons according to the amount of protein bodies per 400 µm2 of cytoplasm area. Double staining (Feulgen/Coomassie Brilliant Blue R250) was used for measurement of nuclear DNA and storage protein content in the same cells. The ploidy of nuclei correlated with total protein body volume (r = 0.97) in Lathyrus tuberosus cotyledon cells.
Key words: Lathyrus tuberosus, seed development, embryo, cotyledon, endosperm, endoreplication, protein bodies.