A seed distribution element (1) includes:-a sowing disc (16) rotated by a motor-driven transmission shaft (20)-a housing (10) with a fixed portion (11) in which the shaft (20) is supported and a portion (12) movable relative to the fixed portion and can be closed against it, with a seed collection chamber (15) in the fixed portion (11) and a pneumatic suction chamber (17) in the movable portion (12),-the sowing disc (16) being interposed between the portions (11, 12) and having opposed surfaces (16a, 16b) delimiting the chambers, and provided with a ring of selector holes (23) extending between the opposed surfaces,-means for producing a pressure differential between the opposed surfaces in the region of a circumferential segment of the ring of holes, including the pneumatic suction chamber, and-a seal (24) on the movable portion (12) capable of sliding contact with the facing surface (16a) of the disc (16) when the portions are closed against one another,-a thrust -bearing element (26) of the sowing disc (16), supported rotatably in the movable portion (12), to withstand the axial load produced by the disc (16) on the seal (24).
