Effect of Salt Tolerant Edaphic Microorganisms on Tomato Local Landraces During Germination in Osmotic Stress Conditions

Abstract

Soil salinization is one of the limiting factors in horticultural production. Microorganisms can confer tolerance to various stress factors, including salinity, and also improve mineral nutrition of host plants. Our researches aim to assess the effect of some salt tolerant bacteria on germination of tomato seeds in saline stress conditions. Seeds from three tomato local landraces were germinated in different concentrations of saline solutions. A part of seeds was not inoculated with any bacterium, meanwhile the rest of seeds were inoculated with three different strains of edaphic bacteria isolated from a saline soil of Timis county, Romania. From a collection of bacterial strains the three most salt resistant were used for inoculation. After 16 days the germination rate and the development of roots were assessed.  In terms of germination rate, the most recommended combination in our study proved to be tomato landrace Tarnova 673-bacterial strain Rh1, which presented maximum germination rate, even at 130mM NaCl saline solution. The length of roots was different depending on the combination of tomato-bacterium genotypes. In some cases, the same bacteria couldn`t alleviate the impact of salinity on root development, meanwhile in case of the same combination, tomato landrace Tarnova 673-bacterial strain Rh1, the root length was the same in 100 mM and 130 mM saline solutions as in water. The influence of microorganisms on germination of tomato seeds depends on the type of plant landrace, bacterial strain and degree of salinity so there is no general pattern in each case. Though successful plant landrace-bacterium strain combinations can be identified.