Identification and characterization of the water gap in physically dormant seeds of Geraniaceae, with special reference to Geranium carolinianum

摘要: BACKGROUND AND AIMS Physical dormancy in seeds of species Geraniaceae is caused by a water-impermeable palisade layer the outer integument seed coat and closed chalaza. The chalazal cleft has been reported to be water gap (i.e. location initial entry) innately permeable Geraniaceae. primary aim this study was re-evaluate characterize its morphology anatomy physically dormant Geraniaceae, with particular reference G. carolinianum. METHODS Length, width, mass, germination two types (light brown dark brown) carolinianum were compared. Location, characterized using free-hand microtome tissue sectioning, light microscopy, scanning electron dye tracking, blocking seed-burial experiments. KEY RESULTS Treatment dry heat colour change cells adjacent micropyle. When placed water, 'hinged valve' (blister) erupted at site change, exposing gap. water-gap region differs from those rest coat. similar carolinianum, columbinum, molle pusillum that closely related Erodium cicutarium. CONCLUSIONS Dislodgment swollen micropyle open it clear uptake takes place through not via opening as previously reported. This ('hinged valve gap') gaps described for other families morphology,