The plant gets its water, and water for the vegetable, from the ground via the roots. Usually the cut vegetable will never contain more water than it does at harvest. The quality, firmness, freshness and crispness of vegetables depends in large part on the amount of water in them. To look good, vegetables must contain as much water as possible. This means that every effort should be made to keep water in the vegetables after they're harvested.
Vegetables lose water because they are alive and respiring.
The respiration reaction produces heat and water. So reducing the respiration rate helps to conserve water. Cooling vegetables is the best way to do this. Various kinds of plastic packaging can help to slow down water loss from vegetables. However , don't store vegetables for lengthy periods in contact with liquid water.