Abstract:

The structure of the bordered pit membrane on the fir tracheid was studied through the observation using scanning electron microscope.As a result,torus of the bordered pit on the fir tracheid can be seen clearly,and the change of the thickness from torus to margo is not obvious.The microfibrils of the margo mainly distribute radiately,part of them exist tangently and slantingly.Only bordered pit membrane in sapwood of the fresh wood cover nothing,while the others cover with amorphous materials.Same as the torus of the heartwood in fresh wood,the torus of sapwood in air-dried wood and springwood in heartwood are all sunken with much warty layer on the pit border.

Key words: Cunninghamia lanceolata, tracheid, bordered pit membrane, margo, torus, microfibril