A system for the transverse movement, centralised and with limited effort, of the covering sheets and/or nets of the protection structures (G, G) of rows (F) of plants, wherein each sheet has a longitudinal side (104) secured to the longitudinal cable (2) of a related row and has the other longitudinal side (204) movable and for this purpose provided with rings or other suitable means (5) to be able to run on the fixed transverse cables (3) of said structures (G, G) and, always for the purpose of movement, this side (204) is secured to transverse pulling cables (7), positioned above and preferably at a height slightly greater than the height of said fixed transverse cables (3) and of the fixed longitudinal cables (2) of the structures (G, G) so as not to interfere with these fixed cables (2, 3). Below the sheets (4) there are provided supplementary and at least flexible cables (14), all or part of which can be fixed, but which are preferably movable together with and in the same direction as the pulling cables (7). These supplementary cables (14) have the function of maintaining the sheets (4) in a raised position at all times and to ensure the complete and correct transverse reduction of the overall dimension thereof, with retraction folded in a bellows-like manner above each row and to tie the same sheets (4) in the retracted position. The sheets are positioned between the pulling cables (7) above and the supplementary cables (14) below so as to substantially float between these same cables, to prevent friction and wear of the system during the extension and retraction of the same sheets (4).Linvention concerne un système de mouvement transversal, centralisé et avec un effort limité, des feuilles et/ou filets de couverture des structures de protection (G, G) de rangées (F) de plantes, où chaque feuille comporte un côté longitudinal (104) fixé au câble longitudinal (2) dune rangée associée et lautre côté longitudinal (204) mobile, et pour cela il est pourvu danneau
