The possible interaction of ammonium and auxin polar transport on root system architectures in the two ecotypes of Arabidopsis thaliana

Figures & data

Table 1. Results of three-way ANOVA showing F-values and level of significance for total root length, primary root length, lateral root length, and lateral root numbers of two ecotypes of Arabidopsis thaliana at different concentrations of ammonium and TIBA.

Factor or interaction	TRL	PRL	LRL	LRN
TIBA	45.486**	3.343*	72.807**	103.558**
Ammonium	37.175**	46.843**	56.713**	26.402**
Genotype	104.024**	233.929**	55.755**	16.677**
TIBA × ammonium	4.727**	3.707**	2.015	2.511*
TIBA × genotype	7.889**	6.037**	2.895	5.093**
Ammonium × genotype	10.198**	19.689**	6.242**	1.575
TIBA × ammonium × genotype	3.251**	2.041	1.853	3.088**

*p < 0.05; **p < 0.01.

Figure 1. Root system architecture of Col-0 and Ler-2 grown on the vertical agar plate culture containing various concentration of ammonium and TIBA.

TRL: Total root length (A and B); PRL: primary root length (C and D); LRL: lateral root length (E and F), LRN: lateral root number per plant (G and H). Arabidopsis ecotypes were grown for 14 days on a vertical agar plate. The MGRL medium (Fujiwara et al. 1992) contained no nitrogen, but was supplemented with 10 µM KNO₃, and was used as a basic medium. The medium was supplemented with either 0, 0.5, 1, or 5 mM NH₄Cl, and with either 0, 0.1, or 1 µM TIBA. Bars indicate mean values (n = 30–56), and significant differences between Col-0 and Ler-2 indicated as following; *p < 0.05 or **p < 0.01. The values were compared with one-way ANOVA followed by Bonferroni, and significant differences at p < 0.05 within each line are indicated by different letters.

Table 2. Results of two-way ANOVA showing F values and level of significance for total root length, primary root length, lateral root length, and lateral root numbers of two ecotypes of Arabidopsis thaliana at different concentrations of ammonium and TIBA.

Factor or interaction	Ecotype	TRL	PRL	LRL	LRN
TIBA	Col-0	32.233**	5.141**	45.520**	58.614**
	Ler-2	14.407**	1.941	29.767**	48.727**
Ammonium	Col-0	15.428**	9.596**	14.960**	12.043**
	Ler-2	48.091**	309.232**	51.539**	17.239**
TIBA × ammonium	Col-0	5.548**	3.321**	2.564*	2.693*
	Ler-2	1.543	1.276	1.131	2.905*

*p < 0.05; **p < 0.01.

Figure 2. TIBA-dependent change of root system architecture in Col-0 and Ler-2 at 0.5 mM ammonium.

TRL: Total root length (A); PRL: primary root length (B); LRL: lateral root length(C); LRN: lateral root number per plant (D). Col-0 and Ler-2 were grown for 14 days on a vertical agar plate. The MGRL medium (Fujiwara et al. 1992) contained no nitrogen, but was supplemented with 10 µM KNO₃, and was used as a basic medium. The medium was supplemented with 0.5 mM NH₄Cl, and with either 0, 0.1, or 1 µM TIBA. Bars indicate mean values (n = 9–13), and significant differences between Col-0 and Ler-2 indicated as following; *p < 0.05 or **p < 0.01. The values were compared with one-way ANOVA followed by Bonferroni, and significant differences at p < 0.05 within each line are indicated by different letters.

Figure 3. Ammonium-dependent change of root system architecture in Col-0 and Ler-2 at 0 µM TIBA.

TRL: Total root length (A); PRL: primary root length (B); LRL: lateral root length (C); LRN: lateral root number per plant (D). Col-0 and Ler-2 were grown for 14 days on a vertical agar plate. The MGRL medium (Fujiwara et al. 1992) contained no nitrogen, but was supplemented with 10 µM KNO₃, and was used as a basic medium. The medium was supplemented with either 0, 0.5, 1, or 5 mM NH₄Cl. Bars indicate mean values (n = 11–14), and significant differences between Col-0 and Ler-2 indicated as following; *p < 0.05 or **p < 0.01. The values were compared with one-way ANOVA followed by Bonferroni, and significant differences at p < 0.05 within each line are indicated by different letters.

Fujiwara T, Hirai MY, Chino M, Komeda Y, Naito S 1992: Effects of sulfur nutrition on expression of the soybean seed storage protein genes in transgenic petunia. Plant Physiol., 99, 263–268.

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