Medium and techniques for induction and growth of monocotyledonous and dicotyledonous plant cell cultures1

The composition of a medium is described that proved useful to culture callus of a variety of monocotyledonous and dicotyledonous plants. Growth on the medium was often better than on some other excellent media. In addition to supporting rapid cell growth, a soft, friable type of colony growth was often obtained. This type of loose, friable cell growth facilitated work with single cells and the enzymatic removal of cell walls in related studies. A high level of auxin-type growth-regulating substances (AGRS)generally favored cell cultures of n~onocotyledonous plants, while low levels of cytokinin were essential for most dicotyledonous cell cultures. Some cultures of dicotyledonous plant cells adapted to a cytokininfree medium containing a high level of 2,4-dichlorophenoxyacetica cid (2,4-D)orp-chlorophenoxyacetic acid CpCPA). The preferred AGRS were 2,4-D and pCPA. Citrate, succinate, and 2(N-morpholino)ethane sulfonic acid (MES)were effective medium buffers, but phosphate alone seemed adequate to buffer the medium at pH 5.8-5.9.