فهرست مطالب khosrow manoochehri kalantari

Soil and water salinity are the most important problems that limit crop production, especially in the arid and semi-arid regions. This study was conducted to investigate the effect of growth-promoting bacteria and selenium nanoparticle pretreatment on increasing the tolerance of the Chenopodium quinoa plant to salinity. A factorial experiment was conducted in a completely randomized design with three replications. Experimental treatments consisted of selenium nanoparticles at a concentration of 1 mg L-1, Bacillus cereus (BW) and Pseudomonas fluorescens (Ps) and three different levels of saline solution with concentrations of 0, 200 and 400 mM sodium chloride. The results showed that quinoa seeds soaking in selenium nanoparticle solution and PGPRs by increasing photosynthetic pigments (up to about 96% in Se+BW pretreated plants), compatible solutes (approximately 65% increase in prolin content in Se+Bw treatment), reducing oxidative stress (increased the activity of some antioxidant enzyme in about 100%), protecting the cell membrane (decreased the MDA up to 32%) and reducing sodium uptake (in about 23% in Se+Ps pretreated plant) improve plant growth and increase the quinoa resistance at salinity conditions. The results of this study showed that Se, although not essential element for plants, can improve growth and morphological parameters of the plant under salinity stress at low concentrations and it has more effects in the presence of PGPRs. So, it is suggested that these two biostimulators can be used together for protecting plants from salinity damaged and this strategy could be applied for sustainable agriculture. In addition, since most of the positive functions of these bacteria were not affected by salinity stress, so this type of bacteria can be used with selenium in saline soils.

Salinity stress is one of the main limiting factors for optimum agricultural productivity of safflower, Carthamus tinctorius L., in arid and semi-arid regions. It could leads to significant changes in plant biochemical, physiological, and growth traits. Salinity induced endogenous rise in jasmonic acid and its methyl esters (MeJA) has been reported. In the present study, effects of salinity stress (6 and 12 ds m-1) and the exogenous application of MeJA (0.1 and 0.5 mM) on the leaf number, shoot fresh weight, shoot length, chlorophyll a/b, soluble sugar, proline, and malondialdehyde (MDA) contents were investigated in two safflower varieties (Isfahan and IL111). Salinity stress negatively affected the growth of both varieties. Lipid peroxidation was not observed in Isfahan variety, but it significantly increased in the salinity resistant safflower, IL111. Soluble sugar and proline as the important osmoprotectants and free radical scavengers were elevated by salinity stress. Exogenous application of MeJA to the salinity stress-imposed plants slightly improved the growth due to inductions in the rate of photosynthesis; however, MeJA application impaired the growth of non-stressed plants because of induction of stomatal closure and as a result reduced photosynthesis.

In this study, the role of salicylic acid pre-treatment (0.01, 0.1 mM was investigated) in inducing salt tolerance in sweet basil. Results showed germination percentage, length of shoot and root, fresh and dry weight of leaf, and photosynthetic pigments were decreased in response to high salinity but the lipid peroxidation, coefficient allometry, and soluble sugars increased. In plants pre-treated with salicylic acid (especially 0.01 mM) the adverse effects of salinity on all measured parameter were alleviated.