Table 5. Symbiotic properties of partially effective and ineffective mutants.

Inoculum strain	Genotype	Mean wet foliage weight in mga	% effectiveness based on wet weight	Acetylene reductionb
none		19.1±3.0**	22.2	0
R7A	Wild-type	86.0±32.2	100	100±35
JS24	msi158::lacZ	59.2±9.8*	68.8	51.5±18.2*
JS27	Δ [msi262-263]:: Ωkan	64.2±22.7	74.6	72.6±33.5
JS42	nifQ::lacZ	61.9±12**	71.9	64.0±15.4*
JS28	Δ [fdxN-fixU]:: Ωkan	17.46±11.6**	20.3	0
JS29	Δ [nifZ-fixU]:: Ωkan	23.6±8.3**	27.4	0
JS30	ΔfixU:: Ωkan	67.5±21.7	78.4	103±22.2

^aMean wet foliage weight of 30 plants ± Standard Deviation. Data were analysed using the Students T-test. ^b Percentage of acetylene reduction relative to R7A. Nitrogen fixation activity was measured as the amount of C₂H₂ reduced (µmol h⁻¹) per plant root for 10 plants ± standard deviation. Data were analysed using the Students T-test. A single asterisk represents P<0.05 and two asterisks P<0.005 when compared to R7A.