Non-woody plants depend on the water stored in the cells of the stem for support.Wilting occurs in non- woody plants when water loss through the aerial parts of the plant exceeds water absorption by the roots. Cells the plants lose their turgidity (stiffness) and the plant droops.
Wilting can be important to the plants because the leaf surfaces are protected from the direct rays of the Sun and the stomata close. Water loss from the plants will be reduced. Normally, a plant which has wilted will remain in this condition until evening. In the evening, water absorption exceeds water loss and the cells become turgid again.