Relation between root growth traits and physiological indices of two bread wheat cultivars under salt stress

The development of seminal and lateral root system plays a major role in plant access to water and nutrients under abiotic stress, especially salinity. In order to understand the relation between root growth responsesand shoot physiological indices oftwo bread wheat cultivars contrasting in salt tolerance (Kavir and Shiraz), a greenhouse experiment was conducted with two salinity levels (0 and 150 mM NaCl), growing in PVC tubes. Salinity decreases seminal root length, total root length, stomatal conductance, relative water content, chlorophyll index, shoot and root dry weight when compared to control. Although, the values for most traits in salt-tolerant cultivar were more, but seminal root length, total root length and relative water content were less than susceptible ones under salt stress. A significant correlation was observed between root growth characteristics and physiological responses under salt stress. Thus, given the similar effects of salinity on growth characteristics of roots and shoots, it seems that root growth responses can be used as a valuable index for screening salinity tolerance. Because, salinity is caused to reduce the plant's ability to absorb water, resulting in a rapid decline in growth rates associated with a series of physiological changes and finally leads to osmotic stress effects.