Table I.

Effect of isoprene fumigation on net assimilation rates (A) after 4 h of ¹O₂ treatment in young (non-emitting) leaves of M. communis

	Rose Bengal (0.4 μM)			Bromoxynil (50 μM)
	Fumigation	No fumigation	Ratio	Fumigation	No fumigation	Ratio
	87	64	1.36	66	43	1.53
	79	49	1.61	62	49	1.27
	109	84	1.30	57	54	1.53
Average ± se	92 ± 9	66 ± 10	1.42 ± 0.10	62 ± 3	49 ± 3	1.29 ± 0.14

Data are presented as the percentage of A left after the treatment. Also presented is fumigation effect on percentage of A, as the ratio between consecutive fumigation and non-fumigation experiments. Light intensity was 1,000 μmol m⁻² s⁻¹ and leaf temperature was 26°C. Exogenous isoprene was added to give isoprene concentrations of 1 to 5 and 1 to 15 μL L⁻¹ in the leaf air spaces in the RB and BX experiments, respectively. The fumigation effect was significant at P < 0.005 for RB and P < 0.025 for BX (one tailed paired Student's t test). Data represent results of two shrubs each in the RB and BX experiments.