Table 3.

Effect of direct current (DC) voltage and pulse duration on the protoplast damage and cell fusion during the membrane breakdown phase of electrofusion between D. carota subsp. sativus cv. Dolanka and D. carota subsp. gadecaei protoplasts

DC voltage (kV cm−1)	Pulse duration (µs)	Protoplast damagea	Cell fusionb
1.5	40–100	−	±
2.0	< 70	−	±
	70	−	+
	80	+	+
	90	+	+
	100	+	+
2.5	< 70	−	±
	70	−	+
	80	+	+
	90	+  +	multiple
	100	+  +	multiple

^a(-) Protoplast damage not observed; ( +) 1–5 damaged cells or (+ +) 6–10 damaged cells per microscopic field at 20 × magnification

^b(±) Occasional cells showing incomplete fusion, unrepeatable in subsequent repetitions; (+) complete fusion occurred; multiple—fusions between 3 or more cells occurred