A study of the ultrastructure of the shoot apex and leaf cells in two liverworts,with special reference to the oil bodies

Summary In this investigation attention has been paid to the general ultrastructure of the shoot apical and leaf cells in the liverwortsBazzania trilobata andLophozia ventricosa but especially to the different developmental stages of their oil bodies. These species have been chosen because their oil bodies differ from each other in size and shape.The appearance of the different organelles, nucleus, chloroplasts, mitochondria, ER, and Golgi bodies, are in their main features the same as those of higher plants described in the literature. The dark cytoplasm seen in the leaf cells ofLophozia in the vicinity of the oil bodies but without any surrounding membrane when fixed in double fixative 2, seems to be specific to this species. On the other hand, granular dense bodies were visible in the cells of the shoot apex ofBazzania, which shrank in size as the development of the oil bodies proceeded and were lacking in the mature leaf cells.In both species investigated, the oil bodies have the same component parts: (1) an outer membrane enveloping the whole body, (2) inside this, a granular stroma layer of varying thickness enveloping (3) specific globules of varying size and number, each of which is surrounded by (4) a thin inner membrane (Fig. 28).The oil bodies develop in at least two ways and usually in one way for each species. InBazzania they seem to develop from vacuole-like formations in the shoot apex or in the leaf primordia into which substances have segregated. InLophozia they seem to originate by aggregation and fusion of lipid bodies.