Developmental studies of cell differentiation in the epidermis of monocotyledons: I. Allium, rhoeo, and commelina☆

[摘要] Variouscharacteristicsmaketheepidermisofcertainmonocotyledonousplants,particularlythecerealgrasses,favorableforstudiesofcertainphasesofdevelopmentalmorphologyandgenetics.IntheCommelinaceae,Araceae,Gramineae,andotherfamilies,developmentofthestomatalcomplexinvolvesthefollowingepigeneticsequenceofevents.Incertainlocalizedrowsorareas,thecytoplasmoftheprotodermalcellsbecomespolarized,sothatitisdenserandcontainsmoreinclusionsatthedistalendofthecell.Thenucleusthendividesbyamitoticfigureorientedacrossthecytoplasmicgradient.Thechromosomesofthisfigurearesimilaratthetwopolesuntilearlytelophase,whentheproximalnucleusbecomeslargerandmoreweaklystainingthanthedistalone,bothwiththeFeulgentechniqueandwithacetocarmine.Thedistalnucleuseventuallydividestoformthetwoguardcells,butbeforedoingsoitinducesdivisionoftwoormoreofthesurroundingepidermalcells.Sinceinthesecellsthereisalsoacytoplasmicgradient,withadensercytoplasmadjacenttotheguardmothercell,theseinduceddivisionsareasymmetrical,withthenucleusinthecenteroftheepidermalcellbecominglargerandmoreweaklystainingthanthatneartheguardmothercell.Inthisway,subsidiarycellsareformed.IntheCommelinaceae,thesubsidiarycellslateraltotheguardmothercellarealwaysformedbeforethoseproximalanddistaltoit,andaparticularepidermalcelladjoiningaguardmothercellalwayscontributesalateralsubsidiarybeforeaproximalordistalone.InAlliumandotherLiliaceaedifferentiationoftheguardmothercellandguardcellsissimilar,butnosubsidiarycellsareformed.Somepossiblecluestotheexplanationofthissequenceareoffered,andpertinentexperimentsaresuggested.

[学科分类] 生物科学（综合）