If vegetables such as brinjals or lady's fingers become somewhat dry and shrivelled, they are put in water. They start looking fresh again, because water enters inside them. In the absence of any opening, how does water enter the vegetables?

The shrivelled vegetables start looking fresh again when kept in water because the concentration of water is more outside the vegetable and the semipermeable cell membrane allows osmosis to take place. By the process of osmosis, slowly the vegetable absorbs water, in absence of any opening.