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

Opening and closing of stomata is due to the : -

1. Hormonal change in guard cells

2. Change in Turgor pressure of guard cells

3. Gaseous exchange

4. Respiration