Question

When a freshly collected spirogyra filament is kept in a 10 percent pottasium nitrate solution it is observed that the protoplasm shrinks in size what is this phenomenon called

Answer 1

the shrinking of a cell when it is kept in a hypertonic solution (more concentrated solution) is called plasmolysis. spirogyra filament contains mainy cells,  this happens because the cell looses water due to osmosis