After adding, solute in water its water potential decreases and solute potential increases.

• The absorption of water by the solid particles of an adsorbent without forming a solution is called Imbibition.
  
• Imbibants have very high negative water potential. It is called the matric potential. Water has (the highest) maximum water potential (maximum being zero).
  

Pure water (i.e. water with no solutes) has a water potential value of 0. As you add solutes (i.e. sugar or salt) to water, the water potential value is lowered. This, therefore, means that the water potential value for any solution is always negative (as the value is lowered from the starting value of 0). Higher the concentration, lower is water potential.

The pressure potential is usually positive.

The cell will swell when the concentration of solute is more inside the cell than the surrounding. Here the concentration of solute inside the cell is 0.4 M, and out of given solutions, 0.1 M solution has a lesser concentration of solute. So, the cell which is placed in a 0.1 M solution will swell. This phenomenon is called osmosis.

If a difference in water potential exists between the two regions, spontaneous movement of water will take place, provided the movement can occur between them. The direction of flow will be energetically down hill, that is from the region of higher water potential(root hair) to the region of lower water potential(xylem) via cortex from less negative water potential (e.g., - $1$ kPa) to more negative water potential (e.g., - $2$ kPa).

Pure water is with no dissolved solutes hence its potential is highest that is zero, as solute is added to water potential or energy of water becomes negative. Diffusion is movement of substances from their higher potential/energy/concentration to places of lower potential /energy/concentration hence does not require in put of energy.

DPD of cell A=5A=5 bars
DPD of cell B=5−5=0B=5−5=0 bars
DPD of cell C=10−4=6C=10−4=6 bars
DPD of cell D=8−3=5D=8−3=5 bars
As cell B has the lowest value of DPD, therefore water will move from cell B to cells A, C and D.

The phenomenon of breaking up of water into hydrogen and oxygen in the illuminated chloroplasts is called photolysis or photocatalytic splitting of water. It can be depicted as: $4H _{2} O \rightleftharpoons 4H^{+} + 4OH^{-}$
   $4OH^{-}\xrightarrow[Mn^{2} + ,Ca^{2} +, CI^{-}]{Oxygen \,\, evolving \,\, complex} 2H _{2}O + O _{2}\uparrow + 4e^- $

Water potential is the measure of the free energy of water which helps in the movement of water between any two systems. Water moves from the point where the water potential is greater to the point where the water potential is less. Addition of solutes decreases the water potential (becomes more negative). Temperature has no effect on water potential. The water potential of pure water is taken as zero. 

Water potential is generally most negative in mesophyll cell walls because water evaporates from the mesophyll cells into the air spaces in the leaf. If the air surrounding the leaf has less water vapor than the air in the intercellular spaces, water vapor will leave the leaf through stomata. Order of water to move through the plant from the soil to the air ( a process called transpiration).

• Water potential is the potential energy of water relative to pure water in a plant cell or tissue. This can be written as the sum of matrix potential (due to binding of water to cell and cytoplasm), the solute potential (due to concentration of dissolved solutes which by its effect on the entropy components reduces the water potential) and pressure potential (due to hydrostatic pressure, which by its effect on energy components increases the water potential).
  
• Ψw = Ψs + Ψp + Ψm
  
• So the correct answer is "All of these".
  

The liberation of $ O _{2}$ during photolysis of water involves the role of $ Mn^{2+},Ca^{2+}$ and $CI ^{-}$ ions.

Osmotic pressure of the cell sap of root hairs is usually higher than the osmotic pressure of the soil water. Therefore, the diffusion pressure deficit (DPD) and the suction pressure in the root hairs become higher and water form the cell wall enters into then through the plasma membrane by osmotic diffusion.

Following are the correct statements:

Osmosis is the movement of solvent from its higher concentration to its lower concentration across a semipermeable membrane. Movement of water through xylem element to xylem vessels above it occurs due to the cohesive force between the water molecules, suction pressure and transpiration pull.