Nitrogen dioxide accelerates flowering without changing the number of leaves at flowering in Arabidopsis thaliana

Figures & data

Table 1. Application of exogenous nitrogen dioxide (NO₂) accelerated flowering and increased shoot biomass in Arabidopsis thaliana accessions C24, Columbia (Col) and Landsberg erecta (Ler)

Accession	NO2 concentration (ppb)	Average flowering time (days) ± SD (n)	Average dry wt. of shoots (mg per plant) ± SD (n)
C24	0	42 ± 3 (20)	25.2 ± 6.8 (4)
	50	40 ± 3 (20) *	68.5 ± 9.3 (10) ***
Col	0	40 ± 3 (17)	14.3 ± 2.5 (5)
	50	34 ± 1 (26) ***	24.2 ± 5.5 (5) *
Ler	0	29.6 ± 1.5 (19)	11.3 ± 2.6 (5)
	50	27.5 ± 2.1 (22)***	28.2 ± 2.3 (5) ***

All data, excluding average flowering time of Ler, were obtained from our previous studies.^17,18 Plants were harvested at 5, 4, and 4 weeks after sowing for C24, Col, and Ler, respectively (see supplementary material). The number of days after sowing when flower bolts were 1 cm in length was used as a measure of flowering time.²⁰ Statistical significance was assessed using Dunnett's t-test for dry wt. and Student's t-test for flowering time: *, P < 0.05; ***, P < 0.001. Statistical analyses were performed using GraphPad Prism 6.0 (GraphPad Software, La Jolla, CA, USA).

Table 2. Number of rosette leaves per plant at flowering, and average rate of leaf appearance of Arabidopsis (Col-0) plants treated with 0 or 50 ppb NO₂

NO2 (ppb)	Number of rosette leaves per plant^a	Average rate of leaf appearance^b (leaves / day)
0	21.2 ± 2.7 (19)	0.53 ± 0.07 (19)
50	21.5 ± 3.1 (20)	0.63 ± 0.09 (20) ***

Data represent means ± SD (n). Plants were grown and subjected to NO₂ treatment as described in the supplementary material. The number of days after sowing when flower bolts were 1 cm in length was used as a measure of flowering time.^{20 a} Number of rosette leaves per plants were counted at flowering. ^b Number of rosette leaves at flowering was divided by the number of days after sowing at flowering (40 and 34 days for plants treated with 0 and 50 ppb NO₂, respectively¹⁷, see Table 1). ***, P < 0.001. Statistical analyses were performed using GraphPad Prism 6.0 (GraphPad Software, La Jolla, CA, USA).