Several environmental factors adversely affect plant growth
and development and final yield performance of a crop. Drought,
salinity, nutrient imbalances (including mineral toxicities and
deficiencies) and extremes of temperature are among the major
environmental constraints to crop productivity worldwide. Development
of crop plants with stress tolerance, however, requires, among others,
knowledge of the physiological mechanisms and genetic controls of the
contributing traits at different plant developmental stages. In the
past 2 decades, biotechnology research has provided considerable
insights into the mechanism of biotic stress tolerance in plants at the
molecular level. Furthermore, different abiotic stress factors may
provoke osmotic stress, oxidative stress and protein denaturation in
plants, which lead to similar cellular adaptive responses such as
accumulation of compatible solutes, induction of stress proteins, and
acceleration of reactive oxygen species scavenging systems. Recently,
the authores try to improve plant tolerance to salinity injury through
either chemical treatments (plant hormones, minerals, amino acids,
quaternary ammonium compounds, polyamines and vitamins) or
biofertilizers treatments (Asymbiotic nitrogen-fixing bacteria,
symbiotic nitrogen-fixing bacteria and mycorrhiza) or enhanced a
process used naturally by plants to minimise the movement of Na+
to the shoot, using genetic modification to amplify the process,
helping plants to do what they already do - but to do it much better."
