What effect did Bassanio's choice of the leaden casket have on Portia? what effect it had on the development of the action of the play?

In Act III, Scene II, Portia agrees to take Bassanio into the room with the caskets and orders music to be played for him. One of her servants then starts to sing a song in which the rhymes all rhyme with lead. Bassanio speaks directly to the audience and tells them that too many things are gilded and coated with ornaments. He therefore decides to do away with gold, comparing it to Midas' greed. The silver casket he also ignores, saying it resembles money and is therefore too common. He thus chooses the lead casket and finds Portia's picture inside.

Bassanio is overjoyed by the picture and remarks that it is a beautiful "counterfeit". He then takes the scroll and reads it: "You that choose not by the view / Chance as fair and choose as true" (3.2.131-132). Bassanio goes over to Portia with the note, and she offers him everything she owns, including herself. Portia then hands Bassanio a ring as a token of her love and commitment and tells him never to lose it. He promises, telling her that if he ever stops wearing the ring it will be because he is dead.