Table 1. Plant responses to NO₂ exposure measured as: changes in shoot biomass, total leaf area, fruit yield, and shoot contents of C, N, P, K, Ca, Mg, S (or Fe), free amino acids, crude proteins, and NO₂-derived nitrogen (NO₂-N). Shoot content responses other than NO₂-N are expressed as fold changes. NO₂-N is expressed as the proportion of N in the whole plant.

Species	NO2 (ppb)	Fold changeb)													NO2-Nc) (%)	References
		Shoot biomass	Total leaf area	Fruit yield	Element contents per shoot								Free amino acids per shoot	Crude proteins per shoot
					C	N	P	K	Ca	Mg	S	Fe
Arabidopsis thaliana C24	10	2.7	-	-	-	-	-	-	-	-	-	-	-	-	-	2
Arabidopsis thaliana C24	50	2.8	2.6	-	2.3	2.4	2.6	2.1	2.4	1.9	2.5	-	-	-	4.1	2
Arabidopsis thaliana Col-0	50	1.7	-	-	-	-	-	-	-	-	-	-	-	-	-	2
Arabidopsis thaliana Col-0	250	1.1	-	-	-	-	-	-	-	-	-	-	-	-	-	6
Brassica campestris	250	1.2	-	-	-	-	-	-	-	-	-	-	-	-	-	17
Corchorusolitorius	50	1.7	1.4	-	-	-	-	-	-	-	-	-	-	-	-	19
Cucumissativus	100	1.7	3.5	-	1.7	1.8	1.1	1.6	1.3	1.7	-	2.2	-	-	14	18
Cucurbitamoschata	200	1.6	1.1	-	1.8	2.1	1.3	1.8	1.5	1.9	-	2.5	-	-	2.2	18
Helianthus annuus	200	2	2.3	-	2.1	2.3	2.1	2	1.4	1.5	-	1.3	-	-	12	18
Hibiscus cannabinus	100	1.4	-	-	-	-	-	-	-	-	-	-	-	-	-	20
Lactuca sativa	50	2.4	1.5	-	2.4	2.3	2.3	2.2	2.7	2.5	-	0.9	-	-	0.23	18
Nicotianaplumbaginifolia	150	1.7	1.9	-	1.7	1.5	1.6	2	1.6	1.7	1.5	-	1.6	1.6	< 3	1
Nicotianatabacum	40	1.0a)	-	-	-	-	-	-	-	-	-	-	-	-	-	16
Solanumlycopersicum	20	1.7a)	-	-	-	-	-	-	-	-	-	-	-	-	-	16
Solanumlycopersicum	50	-	-	1.4	-	-	-	-	-	-	-	-	-	-	9.5	11

^a) Total biomass rather than shoot biomass.^16b)Fold change was estimated by dividing the value for NO₂-treated plants by the corresponding value for control plants. ^c)Plants were fed ¹⁵N-labeled NO₂ and unlabeled nitrate; the content of nitrogen derived from NO₂ (NO₂–N) in aboveground parts of plants was determined by mass spectrometry.² NO₂–N is expressed here as a percentage of total N in the whole plant N.