Table 2.
Fatty acyl chain levels (% of signal) determined by CID–TOF mass spectrometry.
| Fatty acyl chains from complex lipids | Time that the indicated fatty acyl chain is highest | Experiment 1 |
Experiment 2 |
Experiment 3 |
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Level in dark (average % of total CID–TOF MS signal) | Level in light (average % of total CID–TOF MS signal) | p Value | % Change in light compared to dark | Level in dark (average % of total CID–TOF MS signal) | Level in light (average % of total CID–TOF MS signal) | p Value | % Change in light compared to dark | Level in dark (average % of total CID–TOF MS signal) | Level in light (average % of total CID–TOF MS signal) | p Value | % Change in light compared to dark | ||
| 16:0 | 10.99 | 11.16 | 0.237 | 2 | 11.18 | 11.50 | 0.043 | 3 | 12.18 | 12.30 | 0.229 | 1 | |
| 16:1 | Light | 2.32 | 2.70 | 0.000 | 17 | 2.43 | 2.67 | 0.000 | 10 | 2.51 | 2.81 | 0.000 | 12 |
| 16:2 | Light | 0.95 | 1.16 | 0.000 | 22 | 0.92 | 1.08 | 0.000 | 17 | 0.79 | 0.89 | 0.000 | 13 |
| 16:3 | Dark | 10.73 | 10.34 | 0.033 | −4 | 10.41 | 9.91 | 0.001 | −5 | 8.82 | 8.46 | 0.004 | −4 |
| 18:0 | Light | 0.51 | 0.60 | 0.000 | 17 | 0.54 | 0.62 | 0.000 | 15 | 0.56 | 0.67 | 0.000 | 20 |
| 18:1 | Light | 2.92 | 4.96 | 0.000 | 70 | 2.89 | 4.59 | 0.000 | 59 | 3.49 | 5.34 | 0.000 | 53 |
| 18:2 | 18.68 | 18.88 | 0.400 | 1 | 18.67 | 18.86 | 0.344 | 1 | 20.65 | 20.87 | 0.363 | 1 | |
| 18:3 | Dark | 51.53 | 49.19 | 0.000 | −5 | 51.78 | 49.53 | 0.000 | −4 | 49.75 | 47.54 | 0.000 | −4 |
Arabidopsis thaliana plants, grown at 21°C with a 12-h light/12-h dark cycle, were sampled 11 h into the dark and light periods for four dark–light cycles. The experiment was repeated three times. For each experiment, data (five biological replicates at each sampling point) from the dark periods were pooled, and data from the light periods were pooled, producing n = 20 for each. Data were normalized to the total of all detected acyl chain signals. The listed fatty acyl chains accounted for 98.6–99.0% of the total signal for each pool. Data from the end of the dark period and the end of the light period were compared by t-test, and the p values are reported. Values of p < 0.05 are in bold italics. Data from all three experiments showing a significant difference (p < 0.05) in the same direction between light and dark periods are indicated in the second column as “dark” or “light.”