THE IONIC SENSITIVITY OF SECRETION-ASSOCIATED ORGANELLES IN ROOT CAP CELLS OF MAIZE

  • 1 January 1981
    • journal article
    • research article
    • Vol. 23  (2) , 267-272
Abstract
Ionophores selective for Na+ (monensin, dianemycin), for K+ (valinomycin, nigericin), for Ca2+ (A23187, X-537A), the Ca deregulatory substances amiprophosmethyl, fluphenazine, caffeine and the chelator EGTA [ethyleneglycol-bis(aminoethyl ether) N,N''-tetraacetic acid] were applied to intact slime-producing root tips. An accumulation of secretory vesicles within the cells is observed after treatments up to 3 h by all agents. Occasionally the vesicles fuse with one another producing an internal secretion vacuole. Secretory vesicles may or may not remain attached to the dictyosomes but in all cases the cisternae lengthen, ending most often in a cup-shaped form. Application of ionophore plus a 5 mM chloride solution of the corresponding cation had the same effect as treatment with the ionophore alone. These effects are reversible upon withdrawal of the ion-deregulatory agents.