"Osmotic pressure is the minimum pressure that must be exerted to prevent the passage of pure solvent into the solution when two are separated by a semi-permeable membrane" then in concice biology in pg no. 67 in sugar concentration theory why is it written that when the photosynthesis takes place it increases the osmotic pressure WHICH DRAWS WATER FROM THE ADJOINING CELLS INTO THE GUARD CELLS DUE TO ENDOSMOSIS ? My question is osmotic pressure will prevent endosmosis then why is it written that it will draw water from the adjoining cells into the guard cells

1. Plant is autotropic in nutrtion so it performs the process of photosynthesis.
Photosynthesis leads to formation of food in the form of glucose and it also use water as a raw material.Thus due to these all things osmotic pressure of the cell increases.


Osmotic pressure depens on two things.
1.concentration gradient
2.pressure gradient



2. When the cell becomes fully turgid no more water enters into the cell due to osmotic pressure.

But it does not means that osmotic pressure prevents endo osmosis. Osmotic pressure also favours endo osmosis when the concentration of salts in the cell sap of vacuole is high and conc. Of water is low than compared to outside water content. Thus conc. of water outside is high and inside low,water moves inside. Thus the osmotic pressure favours the enterance of water inside the cell.

Hope its clear.
Thank you

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