Water-Light Interaction and its Effect on the Morphophysiology of Cedrela fissilis Vell Seedlings

Plant responses to different light and water availability are variable among species and their re-spective phenotypic plasticity, and the combination between these two abiotic factors can alleviate or intensify stressful effects. This study aimed to evaluate the impacts of exposure time of Cedrela fissilis Vell. seedlings to different water and light availability and the interaction of these factors. Seedlings were submitted to combinations of three shading levels – SH (0, 30 and 70%) and three water regimes based on the water holding capacity (WHC) in the substrate, constituting nine cul-tivation conditions: T1 – 0% SH + 40% WHC; T2 – 0% SH + 70% WHC; T3 – 0% SH + 100% WHC; T4 – 30% SH + 40% WHC; T5 – 30% SH + 70% WHC; T6 – 30% SH and 100% WHC; T7 – 70% SH + 40% WHC; T8 – 70% SH +70% WHC; T9 – 70% SH + 100% WHC. C. fissilis seedlings respond to water deficit, here represented by 40% WHC, regardless of exposure time, and when cultivated in full sun, the stressful effects were enhanced, acting in a synergistic manner. The condition that provided better gas exchange performance and greater total dry mass accumulation for C. fissilis seedlings was 30% shading combined with 100% WHC. C. fissilis seedlings have physiological plasticity and resilience to survive under different water and light conditions.