Figure 5.

The effects of canopy light signals on the AIE of internodes from alpine and prairie plants. AIE of the topmost internodes of ramets from alpine (A) and prairie (B) plants grown under low R/FR (white bars) and green shade (gray bars) growth conditions for 3 d. Control plants (black bars) were grown under light with an unaltered spectral composition. AIE was measured using a constant-load extensometer with a pulling weight of 20 g and is calculated as the difference in the slopes of lines fitted through 10-min intervals before and after the bending point observed due to a change in pH from 6.8 to 4.5. Data points represent means ± se (n = 8–10). Each biological replicate consisted of the topmost internode from different ramets from different pots. Different letters above each bar indicate statistically significant differences (P < 0.05, Tukey's b test). Experiments were repeated twice with similar results.