Table I. Kinematic analysis of the effect of drought on cell division and expansion in the growing maize leaf.
Results are averages of five independent experiments ± se. Statistical significance is based on Student’s t test, and P values > 0.05 are marked as NS (not significant). Parameters are as follows: leaf length (LL; measured on the fifth leaf at the time of harvesting; Supplemental Fig. S1), LER (calculated during the first 3 d after leaf appearance), mature cell length (Lmat), cell production rate (P), cell division rate (D), cell cycle duration (Tc), length of the meristem (Lmer), number of cells in the meristem (Nmer), time in the division zone (Tdiv), cell elongation rate (Rel), and time in the elongation zone (Tel).
| Parameter | Control | Mild Stress | Severe Stress | Percentage Change in Mild/Severe Stress |
|---|---|---|---|---|
| LL (mm) | 727 ± 15 | 603 ± 16 | 436 ± 23 | −17/−40 |
| LER (mm h−1) | 3.0 ± 0.1 | 2.2 ± 0.1 | 1.1 ± 0.2 | −27/−63 |
| Lmat (µm) | 134 ± 6 | 126 ± 7 | 117 ± 8 | NS/NS |
| P (cells h−1) | 22 ± 2 | 17 ± 1 | 9 ± 1 | −24/−58 |
| D (cell cell−1 h−1) | 0.029 ± 0.004 | 0.026 ± 0.003 | 0.016 ± 0.002 | NS/−44 |
| Tc (h) | 26 ± 2 | 28 ± 3 | 48 ± 7 | NS/+84 |
| Lmer (mm) | 13 ± 1 | 10 ± 1 | 10 ± 1 | NS/−26 |
| Nmer | 867 ± 58 | 685 ± 41 | 591 ± 17 | −21/−32 |
| Tdiv (h) | 253 ± 25 | 267 ± 26 | 437 ± 67 | NS/+73 |
| Rel (µm µm−1 h−1) | 0.040 ± 0.002 | 0.032 ± 0.003 | 0.024 ± 0.006 | NS/−39 |
| Tel (h) | 44 ± 3 | 60 ± 8 | 131 ± 30 | NS/+195 |