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Biology and Biotechnology of Environmental Stress Tolerance in Plants, Volume 3

13.4.6 WATER CHANNELS

Because water is involved in so many cells signaling, biological pathways,

and changes in the cell’s water content have a negative impact on the cell’s

operations. Aquaporins (AQP) (plasma membrane and vacuoles) are water

channel proteins that allow water and small neutral solutes to pass across

the cell membrane (Maurel & Chrispeels, 2001; Vera-Estrella et al., 2004).

Plasma membrane-intrinsic AQP and tonoplast-intrinsic AQP are the two

types of AQP found in plant cells based on their location and sequence

homology. Tonoplast has a high-water permeability; the vacuolar space

can act as a buffer against osmotic variations. When a cell is exposed to an

excessive amount of water, such as flooding or submersion, the cytoplasmic

pH drops, causing protonation of the conserved aquaporin residue (Fischer

& Kaldenhoff, 2008). The principal regulators of water balance in plant

cells are water channel proteins in the tonoplast and plasma membrane,

and water-related stress is the most prevalent and significant environmental

factor influencing plants. If a plant cell is exposed to water-related stress,

these proteins regulate its water content to ensure that proteins and enzymes

in organelles and other cellular compartments continue to function properly.

13.5 FUTURE PERSPECTIVE

In agriculture, abiotic stress influences the potential yield decrease in the crop

plants which encourages the study related to how plants respond towards the

abiotic stress. The influence of numerous abiotic stresses on the plant cell

organelle proteome is discussed in this chapter. Future efforts are made to

discover and describe such organelle proteins, which might open up a new

path for abiotic stress research based on the proteome. Finally, we hope that

this chapter has provided fresh perspectives into plant stress responsiveness,

which will be useful in the future development of genetically altered stress-

tolerant crop plants for human benefit, as well as emphasizing the impor­

tance of examining levels of protein abundance within cellular organelles in

response to abiotic stress.

ACKNOWLEDGMENT

The author K. Rakkammal thank the RUSA 2.0 scheme in the form of PhD

fellowship [Grant No. F. 24-51/2014-U, Policy (TN Multi-Gen), Department