4.1.1. Phloem propertiesThe cells in the phloem tissue may contain different cellularproperties, e.g., membrane composition or a different antioxidantsystem, compared to the cells in other tissues. To our knowl-edge, the cellular properties of phloem tissue have not yet beenstudied. However, some data supporting this idea was found in Pas-palum dilatum Poir. After 3 days at 10◦C, ultrastructural change ofthe chloroplasts in the phloem parenchyma preceded that of thechloroplasts in the lower mesophyll. This different rate of changewas also associated with the severity of damage of the upper mes-ophyll