Effetto della radiazione luminosa sulla funzionalità xilematica e sull'accumulo di calcio nel frutto di Actinidia deliciosa

It is well known that in kiwifruit fruit, calcium is involved in fruit storage quality. Light intensity is recognized as the most critical environmental parameter affecting fruit quality in kiwifruit. Effects of the light, on transpiration and water flow into fruit and also on vascular differentiation in berry, have been found in kiwifruit. Hence, the objective of the present paper was to study the effect of the light on the developmental change of xylem functionality and hydraulic conductance in kiwifruit fruit and implications on calcium accumulation. Measurements were carried out during all growing season, in two levels of light conditions: exposed and shaded levels Xylem functionality of the fruit was investigated by dye infusion technique and changes in xylem hydraulic conductance of the fruit was estimated using a pressure chamber method. The results revealed that exposed fruits showed higher xylem functionality and hydraulic conductance and more fruit Ca accumulation compared to the shaded fruits. It may be reasonably concluded that increasing the exposure through appropriated techniques of kiwifruit orchards management, could be a useful tool to increase calcium accumulation and to improve fruit quality