Article Figures & Data
Figures
- Figure 1.
The phot1 receptor mediated primary growth inhibition. A, The growth rates in response to a single pulse of blue light (103 μmol m-2 delivered in 10 s) in etiolated wild-type (white circles), phot1 (white squares), and phot1phot2 (black triangles) mutant seedlings are presented. The dotted line represents the growth rate of seedlings in continuous darkness. The growth kinetics of wild-type seedlings treated with continuous irradiation (102 μmol m-2 s-1) are shown for comparison (black circles). All growth rates are normalized to the dark growth rate (set to “1”). Each data point represents the average growth rate of many (>15) independent seedlings. Error bars have been omitted for clarity and do not exceed 0.06. B, The average normalized growth rate 15 min after a single 50 μmol m-2 blue-light pulse in cryptochrome and phot mutants is shown. The dark growth rate for all genotypes is set to “1” (dashed line). Data points represent the mean growth rate of at least 10 independent seedlings, and error bars represent se.
- Figure 2.
The fluence-response characteristics of phot1-mediated growth inhibition. Dark-grown wild-type seedlings (black circles) were irradiated with a single pulse of blue light ranging in fluence from 10-1 to 104 μmol m-2 or a mock pulse (D). Treatments were delivered in 10 s or less, except of the 104 treatment which was delivered in 100 s. The inhibition measured in phot1 (white triangles) and phot1phot2 (black triangles) seedlings after treatment with 50, 103, and 104 μmol m-2 blue light is presented for comparison. The results are reported as percent inhibition, calculated from the equation (1 - [growth rate at 15 min after blue-light treatment/growth rate at 15 min after a mock pulse] × 100). At least 10 seedlings were measured per fluence per genotype. Error bars represent se.
- Figure 3.
BAPTA suppresses blue-light-induced Ca2+ influx. A pulse of blue light induced a transient rise in aequorin luminescence ([Ca2+]cyt) that was suppressed by treating seedlings externally with the Ca2+ chelator BAPTA. A, The traces shown represent the averages of between 9 and 11 independent trials for each concentration. Error bars have been omitted for clarity. B, The average integrated luminescence (area under the curve in A, minus background) plotted against concentration. Error bars represent se.
- Figure 4.
BAPTA specifically impairs phot1-mediated growth inhibition. The magnitude of blue-light-induced, phot1-mediated growth inhibition was assessed in the presence of different concentrations of BAPTA. The results are presented as “percent of normal inhibition,” which represents the magnitude of inhibition in BAPTA-treated seedlings relative to the inhibition measured in control (no BAPTA) seedlings 15 min after a 50 μmol m-2 blue-light pulse. At least eight seedlings were measured for each BAPTA concentration. Error bars represent se.
- Figure 5.
Growth on BAPTA does not affect phototropism. Seedlings were grown vertically on agar plates containing 0 (black circles) or 300 μm BAPTA (white circles) and then were irradiated with continuous unilateral blue light at a fluence rate of 2.3 × 10-4 μmol m-2 s-1. Phototropic curvature was measured as a change in hypocotyl angle as determined from analysis of stacked images captured every 30 min for 120 min. Error bars represent se.
