Table 2.

Genetic Interactions between abi8 and Ethylene Response Loci

	Seedling Morphology on ACC Triple Response				ABA Sensitivity
Genotype	−	+	abi8-Like	(n)	Germination	(n)
Ws	0	100	0	(100)	0	(315)
abi8/+	0	71.4	28.6	(56)	23	(513)
ein2	100	0	0	(100)	0	(100)
abi8/+ ein2	75.4	0	24.7	(292)	28	(500)
abi8/+	0	73.9	26.1	(46)	22.3	(417)
ein3	100	0	0	(100)	0	(205)
abi8/+ ein3	73.4	0	26.6	(726)	19.7	(680)

Ethylene sensitivity was assayed by plating seeds on 10 μM ACC and scoring seedling morphology after 4 d in the dark at 22°C; the triple response was scored as maintenance of an apical hook, failure to expand cotyledons, and radial swelling. abi8-like seedlings were distinguished from those displaying the triple response by their reduced apical hooks and enhanced radial swelling of the hypocotyl. The ein abi8 double mutants show complete loss of the apical hook. ABA sensitivity was assayed by measuring germination and hypocotyl swelling after 8 or 9 d of incubation on 3 μM ABA for the ein2 and ein3 monogenic and digenic lines, respectively. The results are expressed as a percentage of the total number of seeds plated (n).