DEVELOPMENTAL REGULATION OF PECTIC POLYSACCHARIDES IN THE ROOT-MERISTEM OF ARABIDOPSIS

JIM 5, an antibody that recognizes a relatively unesterified pectic ep itope, distinguishes between dividing (meristematic) and non-dividing (central cells of the quiescent centre) cells in the Arabidopsis root tip, indicating that non-dividing cell walls contain higher levels of relatively unesterified pectin than dividing cells. JIM 7, an antibody that recognizes a relatively methyl esterified epitope, labels all ce ll walls uniformly throughout the root, suggesting that there is littl e variation in the relatively methyl esterified pectic component in th e two cell types. These observations suggest that the characteristics of cell walls in the root tip result in part from modulations in the a mount of unesterified and non-methyl esterified pectin.