I have John Powrie who married Isabella Bruce. They had 5 children; John b 1833, Elizabeth b1835, Jean b. 1838, James b. 1843 & Henry b. 1846. Isabella must have died between the birth of her last child (Henry) and September 1857 as John, a widower, married Elizabeth or Isabella Hepburn in Dundee. They went on to have 4 children.
I can find no record of Isabella Bruce's death in the GROS so assume she died pre-1855.