Figure 4.

The gravitropic response of roots of wild-type and transgenic plants are different on high and low Ca²⁺ concentrations. A, Vertical growth of 4-d-old wild type (Wt), vector control (C2), and two independent InsP 5-ptase transgenic lines (2-6 and 2-8) was monitored after 24 h in the dark on either medium containing no added Ca²⁺ or medium containing 10 mm Ca²⁺. B and C, Gravitropic bending of 4-d-old wild type (Wt), vector control (C2), and two independent transgenic lines (2-6 and 2-8) was monitored after 6 (B) and 24 h (C) of gravistimulation in the dark on either medium containing no added Ca²⁺ (white bars) or medium containing 10 mm Ca²⁺ (gray bars). Bending is plotted as the average from two independent experiments ±sd (n = 40 roots/experiment). There were statistically significant differences in the bending of each line between the no added Ca²⁺ versus the 10 mm Ca²⁺ medium (P < 0.1 using a Student's t test).