Sucrose will change osmolarity of solution. Once cell is in higher sucrose solution, there will be difference in osmolality between cytoplasm of cells and outside the cell, hence sucrose will flow in to keep balance of osmolarity. Cell will swell and aid in rupture process.

This phenomenon is important how kidney filters water and in several biological system. Medicines are designed for kidney functions on osmolarity basis.

Even:

On the other hand, if appropriate osmolrity of sucrose or glycerol is maintained outside cells, those cells can be frozen and thawed to avoid crystallization of water inside cell during freezing process, this just a food for thought:

DNA extraction: Addition of sucrose/glucose will increase the osmotic pressure outside the cells, resulting in cell break due to change in osmotic pressure in and out of the cell.

I recommend the replies of Subhash and Prasanth. Once the cells experience the change in osmolarity due to the higher external sucrose, they tend to plasmolyse and lose water. They are now in a state for rapid uptake of external water so when aqueous lysozyme or other enzymes or lytic agents are then added in water/buffer (but no sucrose) following sucrose treatment they are rapidly taken up by the plamolysed cells and this aids their action in lysis of the cells.

Thank you Subhash C. Juneja, Prasanth Manohar, Mary Phillips-Jones.

addition of sucrose/glucose does not mean that it result in cell break and rupture cell membrane. it makes in and out of the cell isotonic so that cell membrane doesn't break. because if cell breaks, chromosomal DNA is also ruptured and broken and this could lead to confusion of distinguishing plasmid DNA from chromosomal DNA