From your knowledge of physiology,can you think of some methods to increase the life span of cut plants in a vase?

(N/A) To increase the life span of cut plants in a vase,the following methods can be used:
$1$. Recutting the stems: Cut the base of the stem at an angle under water. This prevents air embolisms (air bubbles) from entering the $xylem$ vessels,which would otherwise block the upward movement of water and nutrients.
$2$. Use of preservatives: Adding sugar (sucrose) provides an energy source for the cells,while adding a small amount of bleach or citric acid helps inhibit the growth of bacteria and fungi that can clog the $xylem$.
$3$. Application of phytohormones: Treating the cut plants with cytokinins can delay senescence (aging) by maintaining protein synthesis and chlorophyll levels in the leaves.