question_answer 5)

Differentiate between the following (a) Diffusion and osmosis (b) Transpiration and evaporation (c) Osmotic pressure and osmotic potential (d) Imbibition and diffusion (e) Apoplast and symplast pathways of movement of water in plants (f) Guttation and transpiration  

Answer:

(a) Differences between Diffusion and Osmosis  

S.N.	Diffusion	Osmosis
1.	It is a movement of molecules from high concentration to low concentration.	It is a movement of molecules from high concentration to low concentration through semiperme able membrane.
2.	It does not require any driving Force.	It occurs in response to a driving force.

(b) Differences between Transpiration and Evaporation  

S.N.	Transpiration	Evaporation
1.	It is the loss of water through the aerial parts of plants. .	It is loss of water from free surface of water.
2.	It occurs in living tissues.	It occurs in non-living surfaces.
3.	It is both physical and physiological process. ..	It is only a physical process. controlled by environmental factors.

(c) Differences between Osmotic Pressure and Osmotic Potential  

S.N.	Osmotic Pressure	Osmotic Potential
1.	It is the pressure required to stop the movement of water molecules through a semipermeable membrane.	It is the amount by which water potential is reduced-by the presence of solute.
2.	Osmotic pressure is the positive pressure.	Osmotic potential is negative.

(d) Differences between Imbibition and Diffusion  

Imbibition	Diffusion
It is a special type of diffusion, random where water is absorbed by solids-colloids causing them to increase in volume. For example, absorption of water by dry seeds and dry wood.	In diffusion, molecules move in a fashion. It is not depedent on a living system.

(e) Differences between Apoplast and Symplast Pathway of Movement of Water  

S. N.	Apoplast	Symplast
1.	It is the system of adjacent cell walls that is continous throughout the plant except casparian strips of the endodermis of the roots.	It is the system of interconnected protoplast.
2.	Water moves through the intercellular spaces and the walls of cells	Water travels through the cytoplasm of cells and intercellular movement is through plasmodesmata.
3.	Movement does not involve crossing the cell membrane.	Water has to move in celts through the cell membrane.

(f) Differences between Guttation and Transpiration  

S. N.	Guttation	Transpiration
1.	It occurs through hydathodes, present at the vein ends.	It occurs through general surface, stomata and lenticles.
2.	It occurs in leaves only.	It can occur through all aerial parts.
3.	It does not occur in deficient water conditions and never leads to wilting.	It can occur in water deficient conditions, leading to wilting.
4.	It is regulated by humidity, temperature and presence of  water in soil.	It is regulated by a number of external and internal factors such as relative humidity, temperature opening and closing of stomata, etc.