Which of the following facilitates opening of stomatal aperture?

1. Decrease in turgidity of guard cells
2. Radial orientation of cellulose microfibrils in the cell wall of guard cells
3. Longitudinal orientation of cellulose microfibrils in the cell wall of guard cells
4. Contraction of outer wall of guard cells

Cellulose microfibrils are arranged radially rather than longitudinally which makes easy for the stomata to open.