9.2
Environmental Constraints Limiting Agricultural
Production
Food is the basic necessity of life and to fulfil this need, agriculture plays a very
crucial role. Several strategies have been applied in the agricultural field to increase
the yield of crops but still the crop plants come across various constraints (stress
factors) that hinder their growth and yield. These factors are majorly categorised as
biotic factors (pests, rodents, etc.) and abiotic factors (salinity, drought, heavy metal,
etc.) as depicted in Fig. 9.1. All these stress factors hamper the normal growth and
development of plants and thereby, hinder sustained food production. More than
50% loss in productivity in most of the crop plants has been observed due to abiotic
stresses including drought, salinity, cold and extreme temperature, etc. (Bray et al.
2000; Wang et al. 2003).
9.2.1 Salinity as Major Abiotic Stress
The different abiotic stresses limiting plant growth and metabolism include salinity,
drought, heat, cold, metal stress, etc. Among all these stress factors, salinity has a
major negative impact on plants and pose a major threat to global food security. The
proportion of salinity affected cultivated land worldwide is estimated to be 20% and
this figure is increasing day by day. Salinity of soil can be defined as existence of
high concentration of soluble salts in the soil. Soils having an electrical conductivity
Fig. 9.1 List of stress factors affecting plant growth and metabolism
9 Phytohormones: A Promising Alternative in Boosting Salinity Stress Tolerance in. . .
281
Environmental Constraints Limiting Agricultural
Production
Food is the basic necessity of life and to fulfil this need, agriculture plays a very
crucial role. Several strategies have been applied in the agricultural field to increase
the yield of crops but still the crop plants come across various constraints (stress
factors) that hinder their growth and yield. These factors are majorly categorised as
biotic factors (pests, rodents, etc.) and abiotic factors (salinity, drought, heavy metal,
etc.) as depicted in Fig. 9.1. All these stress factors hamper the normal growth and
development of plants and thereby, hinder sustained food production. More than
50% loss in productivity in most of the crop plants has been observed due to abiotic
stresses including drought, salinity, cold and extreme temperature, etc. (Bray et al.
2000; Wang et al. 2003).
9.2.1 Salinity as Major Abiotic Stress
The different abiotic stresses limiting plant growth and metabolism include salinity,
drought, heat, cold, metal stress, etc. Among all these stress factors, salinity has a
major negative impact on plants and pose a major threat to global food security. The
proportion of salinity affected cultivated land worldwide is estimated to be 20% and
this figure is increasing day by day. Salinity of soil can be defined as existence of
high concentration of soluble salts in the soil. Soils having an electrical conductivity
Fig. 9.1 List of stress factors affecting plant growth and metabolism
9 Phytohormones: A Promising Alternative in Boosting Salinity Stress Tolerance in. . .
281