Investigation of Arabidopsis root skototropism with different distance settings

Figures & data

Figure 1. Experimental setup in this study. Examples of different shade approaches we adopted: (a) treatment of small round Petri dishes (92 × 16 mm) within black boxes with a light source at the growth chamber ceiling. (b) Treatment of large square Petri dishes darkened with black covers with a light source at the growth chamber ceiling. Based on the sizes of the petri dishes, three rows of Arabidopsis seedlings were positioned in a and five rows in B, respectively. Each column was spaced 1 cm (10 mm) apart from each other as the label. To ensure consistent positioning, the inner row of seedlings was aligned with the border of the covers.

Figure 2. Skototropic response of Arabidopsis roots after 96 h growth within small round dishes inserted into the black box. Four lines of Arabidopsis seedlings were adopted: (a) Arabidopsis thaliana (col-0), (b) AtGLR3.7 knockout line (atglr3.7 ko), (c) AtGLR3.7 over-expression line (AtGLR3.7 OE), and (d) AtPIN2 deletion line (pin2 knockout). The circle contains the total number of Arabidopsis seedlings used in the experiment at the following distance settings: 0, 10, and 20 mm. The blue bars, green bars, and yellow bars, respectively, show the percentages of seedlings positively bending toward darkness, seedlings with no discernible bending trend, and seedlings bending away from darkness.

Figure 3. Skototropic response of Arabidopsis roots after 96 h growth with small round dishes darkened with black covers. Three lines of Arabidopsis seedlings were adopted: (a) Arabidopsis thaliana (col-0), (b) AtGLR3.7 knockout line (atglr3.7 ko), and (c) AtGLR3.7 over-expression line (AtGLR3.7 OE). The circle contains the total number of Arabidopsis seedlings used in the experiment at the following distance settings: 0, 10, and 20 mm. The blue bars, green bars, and yellow bars, respectively, show the percentages of seedlings positively bending toward darkness, seedlings with no discernible bending trend, and seedlings bending away from darkness.

Figure 4. Skototropic response of Arabidopsis roots after 96 h growth with large round dishes partially covered with black covers. Three lines of Arabidopsis seedlings were adopted: (a) Arabidopsis thaliana (col-0), (b) AtGLR3.7 knockout line (atglr3.7 ko), and (c) AtGLR3.7 over-expression line (AtGLR3.7 OE). The circle contains the total number of Arabidopsis seedlings used in the experiment at the following distance settings: 0, 10, 20, 30, and 40 mm. The blue bars, green bars, and yellow bars, respectively, show the percentages of seedlings positively bending toward darkness, seedlings with no discernible bending trend, and seedlings bending away from darkness.

Figure 5. Skototropic response of Arabidopsis roots after 96 h growth with square dishes partially covered with black covers. Three lines of Arabidopsis seedlings were adopted: (a) Arabidopsis thaliana (col-0), (b) AtGLR3.7 knockout line (atglr3.7 ko), and (c) AtGLR3.7 over-expression line (AtGLR3.7 OE). The circle contains the total number of Arabidopsis seedlings used in the experiment at the following distance settings: 0, 10, 20, 30, and 40 mm. The blue bars, green bars, and yellow bars, respectively, show the percentages of seedlings positively bending toward darkness, seedlings with no discernible bending trend, and seedlings bending away from darkness.

Figure 6. Comparative perception of darkness in Arabidopsis and human being. The Arabidopsis thaliana seedling (about 100 μm in diameter) positioned at 20 mm from darkness is equivalent to a person with a diameter of 0.7 m being situated 140 m away from darkness.

Data availability statement

The authors declare that all relevant data supporting the findings of this study are available within the paper and its supplementary files. All data for the main figures are provided in Supplementary Data 1. All other data will be available from corresponding authors upon reasonable request.