Fig. 1.

Responses of morpho-anatomical traits of mature leaves of A. pseudoplatanus seedlings to a sudden increase in irradiance. Means and standard errors for carbohydrate-free leaf mass per area (LMA; a), leaf lamina thickness (b), palisade mesophyll thickness (c), spongy mesophyll thickness (d), thickness of upper (e) and lower (f) epidermis are shown. Leaves were sampled on August 5, i.e., prior to transfer to full irradiance (PRE) and 30 days later (TRANS transferred plants, CONT plants left under the original irradiance). Significant contrasts between treatment groups within the same initial growth irradiance are indicated by different letters above bars. For analysis of variance see Table 1. Data for TRANS plants originally grown under lowest irradiance are missing because of the photo-oxidative damage to leaves