Removing the sap keeps the stem able to absorb water. Daffodils and tulips should be cut up to the green portion of the stem, as they do not drink from the white bottom part of the stem. Flower arrangements should be kept out of direct sun. The room temperature should not get too warm as fresh flowers last longer if placed in a cooler temperature.
Flower arrangements are in vases or placed in floral foam or oasis.
If the flowers are arranged in oasis, oasis is a spongy foam that soaks up water as a sponge does. The foam acts as a preservative to prolong the life of the flowers. The foam should be watered each day to keep it from drying out. Run your finger over the top of the container the arrangement sits in and you should feel the oasis. I use a long spouted watering can and slowly add water between the container and the oasis so the oasis is always sitting in water.