Soil salinity is an immense problem for agriculture. Excess amount of salt in the soil affects plant growth and development. Nearly 20% of the world's cultivated area and half of the world's irrigated lands are affected by salinity 1,2 .In hot and dry regions, most crops are grown under irrigation, and inadequate irrigation ABSTRACT Ethylene synthesis is accelerated in response to environmental stresses like salinity. Excess amount of ethylene has a negative impact on root elongation, seedlings, growth of leaves in plants. Aim of the work was study the effect of Pseudomonas mendocina containing plasmid carrying gene encoding 1-aminocyclopropane-1-carboxylate deaminase (ACD) on resistance of wheat plant under salt stress. Surface sterilized seeds of wheat plant were germinated in petri plates. Uniformly buds were selected, and were used in pot and greenhouse. Salinity as 172 and 207 mM NaCl were prepared for wheat plant in pot and 207 mM in greenhouse by irrigation of NaCl solution. acdS gene was cloned in P. mendocina and transformed bacterium was used in experiments . Results in pot experiment revealed that in 172mM salinity, cloned P. mendocina in comparison with plants treated by wild type of P. mendocina, exceeding the length of the stem by 11.6%, biomass by 43.7% and root length by % 47.5. In 207 mM NaCl results were as 2.65%, 20.6% and 11.9% respectively. Experiment in greenhouse showed that wheat plants treated by a suspension of cloned P. mendocina, in comparison with those treated by wild type of P. mendocina had 38.8% greater length of stem, 23.3% more root length and 28.6% more biomass. Wheat plants treated by cloned P. mendocina in comparison with plants without bacterial treatment had 43.8% greater length of stem, 5.5% more root length and 28.6% more biomass. It is concluded that enhancement of ACC-deaminase activity resulted in excess resistance of wheat in saline environments.

Objective It is necessary to evaluate the harmful or useful effects of electromagnetic waves on living organisms and determine the threshold of these radiations. In this research, the effect of magnetic fields on the growth of gram-positive ( Staphylococcus aureus ) and gram-negative ( Escherichia coli ) bacteria has been evaluated.Results In Gram-negative bacteria such as E. coli in both magnetic fields 1mT and 2mT at different frequencies, an additive effect was seen on the growth of bacteria. When the frequency increased the trend of increasing bacterial growth, slowed. In Gram-positive bacteria such as Staphylococcus, this effect was less. In 1mT magnetic field, the growth of bacteria was seen but the 2mT field was virtually ineffective and the differences between two groups at different frequencies were not significant. Also, significant changes didn't observe with increasing frequency. Study of bacterial growth in terms of frequency in both case and control groups showed an increasing trend. With increasing frequency from 50 Hz to 150Hz significantly increased the rate of bacterial growth and the growth in the higher frequencies more than lower frequencies. Magnetic field had increment effect on the growth of bacteria. This effect was greater on gram-negative than on gram-positive.

Objective: The effects of electromagnetic waves on the growth of living organisms and the determination of the threshold of these radiations have remained elusive. Therefore, in this research, we have investigated the growth rate of gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria that had been exposed to the different frequencies of electromagnetic fields. Results: The more frequency increased the slower bacteria grew; however, in gram-positive bacteria such as S. aureus, this effect was seen less. The effect of the 1mT electromagnetic field in the growth of S. aureus was significant between the two groups, nonetheless, in the 2mT electromagnetic field, the effect was not significant between the two groups at different frequencies. Noteworthy, no significant change was observed by increasing the frequency in S. aureus exposed bacteria in comparison to the control group. The study of bacterial growth in terms of frequency in both case and control groups showed an increasing trend. Increasing the frequency from 50 Hz to 150Hz, significantly, enhanced the rate of bacterial growth. On the whole, the magnetic field had an increment effect on the growth of bacteria; in fact, this effect was greater on the gram-negative than on the gram-positive bacteria.