REVIEW

Mechanism of Phytohormone Responses Against Salt Stress: a Review

Abiotic stress is defined as the negative impact of non-living factors on living organisms in a specific environment. An unfavourable environmental condition comprising extreme low and high temperature, salinity, drought, water logging, heavy metals etc. pose a complex set of stress condition. Plant responses to those environmental stresses are also complex. The effects of stress are usually measured in terms of plant survival, crop yield, growth (biomass) or primary assimilatory processes which are related to overall growth of plants. Various physiological stimuli and/or stresses control the synthesis of phytohormones in many ways. Again all the molecular biological phenomenon including growth and development of the plants are controlled by the phytohormones at very low concentration. During abiotic stress the biosynthesis and accumulation of different molecules thought to have protective functions in the cells. Some plant growth promoting rhizobacteria (PGPR) may exert a direct stimulation on plant growth and development by providing plants with some of the phytohormones. Among the all abiotic stresses salinity limits the crop’s growth and productivity worldwide. Salinity affects many of the physiological processes starting from seed germination, enzymatic activity, food production to DNA and protein synthesis. Many of the researchers work on the effect of salinity on the physiological activity of the plants, but the mechanism of phytohormones response against salinity are still not assembled in a systematic manner. An attempt is made to establish the comprehensive mechanism of phytohormones responses against salt stress and to know about the adaptation/tolerance of plants in the molecular level as well as systematic approaches during this post genomic era with 164 references.