Effect of using saline irrigation water on biomass production and ions accumulation in kochia (Kochia scoparia)

Biosaline agriculture is one of the approaches to increase crop production under the existing situation of resources. Amongst halophytes, Kochia scoparia has been taken into consideration by researchers. Kochia is a mesohalophytes, C4 plant which has a good adaptability to different soil types. In order to evaluate the salinity effect on ion accumulation of kochia plant and its mechanism for salinity tolerance, a RCBD experiment was conducted with seven levels of saline water (1.5, 7, 14, 21, 28, 35 and 42 dSm-1) using drainage water with three replications in the northern region of Golestan province during 2009. Results showed that salinity significantly decreased biomass production. Salt tolerance of kochia at reproductive (salt tolerance index of 34) and flowering stage (salt tolerance index of 32) was greater than the vegetative growth stage (salt tolerance index of 24). Salinity had a significant effect on the accumulation of Na+, K+ and Cl- and the highest amount of ions were accumulated in leaves. Kochia’s root system played a selective role for absorption and transportation of Na+. Moreover, selective absorption of K+ was increased by accumulating Na+ in root media and maintained the Na/K ratio in plants. Kochia showed high tolerance to accumulation of Cl- in leaves. Results of this study showed that Kochia is a salt excluder halophyte.