Figure 4.
Sensitivity of gudk mutant lines to vegetative drought. Drought stress was applied to 45-d-old wild-type and gudk mutant plants by maintaining a set of plants at 40% FC, whereas the well-watered plants were maintained at 100% FC for 10 d. During the stress period, pots were weighed daily at a fixed time of the day, and water lost was replenished to maintain the required FC. At the end of the stress period, growth and physiological performance were measured. A, Phenotype of mutant lines maintained at well-watered and drought stress conditions for 10 d. B, RWC of leaves at the end of 10 d of drought stress. C to E, Assimilation rate (C), WUEi (D), and efficiency of PSII (E) in light-adapted leaves, measured at 10 d of drought stress. F, Biomass (dry weight) measured at 10 d of drought stress. Values are the means ± se (n = 10). Double asterisks indicate significance at P ≤ 0.01 compared with the wild type as analyzed by the Student’s t test. DR, Drought stress; DW, dry weight; Fv′/Fm′ , maximum photochemical efficiency of PSII during steady-state illumination; WT, wild type; WW, well watered. [See online article for color version of this figure.]