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toxicity. The osmotic stress hikes whenever there is a saline soil

because the soil itself is high in the salts, so it reduces the uptake

activity of minerals and water like calcium and potassium. In salt

stress, the plant which cannot tolerate the stress starts showing arrest

in their growth and in their reproduction with organ detachments. As

well as some acids and compounds get accumulated in plant such

as the jasmonic acid, polyphenolic compounds (Pedranzani et al.,

2003). Levels of anthocyanin also decrease wherever there is a salt

stress, or the land is saline (Daneshmand et al., 2010).

3. Extreme Temperature (Cold, Heat): This stress always shows up

a negative impact whether the temperature is high or low, i.e., heat

stress or cold stress. It directly creates an impact on the plant metabo­

lism. Many drastic effects are observed under temperature change,

it affects the stabilization of proteins or premature leaf senescence,

efficiency of enzymes, and cytoskeleton structure (Morison &

Lawlor, 1999). The rate of seed germination photosynthetic effi­

ciency decreases when the heat stress come across, physical altera­

tions are done in the plasma membrane of a cell, which damages the

electron transport chain, ATP, oxygen-evolving complex and carbon

assimilation mechanism (Scholz et al., 2004). Talking about the

low temperature or cold stress it also creates multiple effects on the

plants. A limiting factor is created by the cold stress ranging from

temperature (0–15°C) which is beyond freezing, it ceases the growth

of plant, done by reducing the amplitude in energy utilization which

ultimately does a reduction in the rate of photosynthesis and produc­

tion of reactive oxygen species.

10.2.2 BIOTIC STRESS AND PLANTS RESPONSES

The biological factors are altering these stresses, such as diseases and insects,

which alters the growth the growth of plant throughout their life span. Plants

usually react to these stresses by developing secondary metabolites, sudden

changes in their cell walls, etc. To stop the functioning of harmful pathogens

or to isolate them on the other hand they are stopping their spreading across

the plant. These sudden changes are known as the Hypersensitive Reactions.

Polyamines accumulation shows that there is a sudden change which is

occurring in the plant or there is an interaction of pathogens whether it is

viral, fungal (Torrigiani et al., 1997; Asthir et al., 2004).