Progress of lignification mediated by intercellular transportation of monolignols during tracheary element differentiation of isolated Zinnia mesophyll cells.
Tracheary element (TE) differentiation is a typical example of programmed cell death (PCD) in higher plants, and maturation of TEs is completed by degradation of all cell contents. However, lignification of TEs progresses even after PCD. We investigated how and whence monolignols are supplied to TEs which have undergone PCD during differentiation of isolated Zinnia mesophyll cells into TEs. Higher densities of cell culture induced greater lignification of TEs. Whereas the continuous exchanging of culture medium suppressed lignification of TEs, further addition of coniferyl alcohol into the exchanging medium reduced the suppression of lignification. Analysis of the culture medium by HPLC and GC-MS showed that coniferyl alcohol, coniferaldehyde, and sinapyl alcohol accumulated in TE inductive culture. The concentration of coniferyl alcohol peaked at the beginning of secondary wall thickening, decreased rapidly during secondary wall thickening, then increased again. These results indicated that lignification on TEs progresses by supply of monolignols from not only TEs themselves but also surrounding xylem parenchyma-like cells through medium in vitro.
Hosokawa
M
M
Department of Biology and Earth Sciences, Faculty of Science, Ehime University, Matsuyama, 790-8577 Japan.
Suzuki
S
S
Umezawa
T
T
Sato
Y
Y
D019659:Asteraceae / Q000166:cytology / Q000378:metabolism*; D001693:Biological Transport, Active; D002450:Cell Communication / Q000502:physiology; D002452:Cell Count; D002454:Cell Differentiation / Q000502:physiology; D002478:Cells, Cultured; D008031:Lignin / Q000378:metabolism*; D008954:Models, Biological; D010636:Phenols / Q000378:metabolism; D010649:Phenylalanine / Q000031:analogs & derivatives* / Q000494:pharmacology; D010650:Phenylalanine Ammonia-Lyase / Q000378:metabolism; D018515:Plant Leaves / Q000166:cytology / Q000378:metabolism; D013057:Spectrum Analysis
D010636:Phenols; C019145:alpha-aminooxy-beta-phenylpropionic acid; D010649:Phenylalanine; D008031:Lignin; C010559:coniferyl alcohol; D010650:Phenylalanine Ammonia-Lyase