Risposta di specie ornamentali allo stress idrico

The different results in relation to the cultivars in the two steps (seed and seedling growth stages) need further investigation considering the noticeable interest to effectuate a quick and easy screening for evaluation of genotypes to water stress. The response of ornamental shrub seedlings to water stress has considered the plant changes to different water content in the substrate for the whole cultivation period and to frequent cycles of suspension/recovery of irrigation. Results showed that species seemed to be available in environments characterized by scarce water resources, and exhibited a different capacity to increase water efficiency. The tolerance to water stress is linked to morpho-biometrical and physiological changes, which have involved the photosynthesis and stomatal conductivity. In low water availability less tolerant species showed a reduction in leaf area, while the tolerant ones have increased the root systems. Among the physiological mechanisms, the modification of stomatal conductivity appears to be the main strategy to avoid water loss. However, as showed by the many physiological processes investigated, species showed a certain capability (different among the species) to recover their functional efficiency at the end of unfavorable period.