Effect of salinity and inoculation with Azosprillium on carbohydrate production, nitrogen status and yield of barley

Abstract

In order to evaluate the effect of Azosprillium brasilense inoculation on common barley grown in saline condition, a greenhouse experiment was conducted in Azad University, branch of Eghlid, Iran. The experimental design was a factorial based on complete randomized design with four replications. The first factor comprised of four saline water treatments (1 as control, 5, 10 and 15 ds m¯¹) and the second factor included two Azosprillum inoculation levels (inoculated and uninoculated = control). The measured parameters were chlorophyll fluorescence, photosynthesis (Ps) rates, carbohydrates, nitrate, ammonium and protein content, nitrogenase activity, yield and yield components. The results showed that salinity decreased plant height and grain yield (GY) in all levels. GY reduction in the inoculated treatment was lower (12.9%) than that in the uninoculated treatment (29.7%). It can be concluded that by plant height reduction, source efficiency reduced which caused reduction of grain number and grain weight and consequently, reduced GY. It was also observed that grain number was more susceptible to salinity than ear per meter square. Inoculation reduced harmful effects of salinity especially on mean kernel weight and grain number. There was higher starch content in inoculated treatments in comparison with uninoculated one under salinity. Fructan level increased and sucrose level decreased by inoculation, but the upward trend was seen in both traits under salinity. There was high relation between fructan content and photosynthesis rate. The mean values of Fv/Fm and photosynthesis rate reduced in the salinity treatments when compared with the control. Inoculation significantly increased photosynthesis rates at all salinity levels. The highest plant N content was obtained from inoculated treatment in non-saline condition. In the inoculated barley roots, nitrogenase activity (NA) was not severely inhibited by salinity. Generally, inoculation caused plant to cope with stress effectively by increasing fructan content and NO₃/NH₄ ratio and decreased less the whole plant N content and Fv/Fm ratio.

Key words: NaCl, dry matter, photosynthesis, root inoculation.