Table 3.

Effect of protoplast culture medium (PCM) and callus proliferation medium (CPM) on the formation of callus from G. decumbens protoplasts after 4 wk of culture

Protoplast culture medium	Callus proliferation medium	Degree of callus formationa
PCM1	CPM1	++++
	CPM2	+++
	CPM3	+++
	CPM4	++++
PCM2	CPM1	+
	CPM2	+
	CPM3	+
	CPM4	++

^aDegree of callus formation is expressed as follows: + very small callus covering not more than a quarter of the agarose bead surface, ++ small callus covering not more than a half of the agarose bead surface, +++ callus not exceeding the surface of the agarose bead, and ++++ callus exceeding the surface of the agarose bead