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).Cette invention concerne un élément de distribution de semences (1) comprenant : un disque de semis (16) dont la rotation est assurée par un arbre de transmission motorisé (20) un capot (10) qui comporte une partie fixe (11) supportant larbre (20) et une partie (12) mobile par rapport à la partie fixe et pouvant se fermer contre cette dernière, la partie fixe (11) contenant une enceinte de collecte des semis (15) et la partie mobile (12) contenant une enceinte daspiration pneumatique (17) le disque de semis (16) étant intercalé entre les parties (11, 12), ses faces opposées (16a, 16b) délimitant les enceintes, le disque étant équipé dun disque dorifices de sélection (23) situé entre les faces opposées un système qui produit un différentiel de pression entre les faces opposées dans la zone dun segment circonférentiel du disque dorifices,
