Seeds subjected to osmotic stress require more time to adjust internal osmotic potential
in accordance with the external environment (MUNNS & TESTER, 2008).
The first onus is the reduction in the osmotic potential
of the cultivation medium, which may reduce water consumption, leading to water stress, a situation that triggers mechanisms of adjustment to the stress condition and directly influences the water content in the plant (Paulus et al., 2012) and dry matter allocation (Hasanuzzaman et al., 2014).
A given soil osmotic potential
can be indefinitely set with the use of PEG, which cannot be reproduced by other water deficit-inducing methods.
For that, experiment II was carried out with osmotic potential
of -0.1; -0.2; -0.3; -0.4 and -0.5 MPa.
The osmotic potential
of the soil solution can be calculated as follows:
So, the decline in growth parameters especially fresh and dry weights of the plants under increasing salinity levels is linked to a rise in osmotic potential
in water stressed plants (Turner, 1981) which may be due to high extra cellular solute concentration or decreased volumes of cell under drought.
The difference in osmotic potential
between the solution and the fruit sample resulted in a high diffusion rate of the solute and water [3, 6, 30].
The reduction in osmotic potential
can be attributed to accumulation of compounds such as amino acids and polyols and thus enable the plants to maintain turgor and growth under these unfavorable growth conditions .
Earlier studies reported that PEG can induce stress to the plant in a relatively controlled manner through modifying the osmotic potential
of the nutrient solution culture (Meneses et al., 2011; Zhu et al., 1997).
Acclimation of plants to water deficit is the result of different events, which lead to adaptive changes in plant growth and physio biochemical processes, such as changes in plant structure, growth rate, tissue's osmotic potential
and antioxidant defenses.
After 7 days interval again grass was irrigated and grass samples were taken to determine non stressed osmotic potential
on 11th of July 2013.