Effect of phosphate solubilizing microorganisms on quantitative and qualitative characteristics of maize (Zea mays L.) under water deficit stress.

The effect of seed inoculation by phosphate solubilizing microorganisms on growth, yield and nutrient uptake of maize (Zea mays L. SC. 704) was studied in a field experiment. Positive effect on plant growth, nutrient uptake, grain yield and yield components in maize plants was recorded in the treatment receiving mixed inoculum of Glomus intraradices (AM) and Pseudomonas fluorescens (Pf). Co-inoculation treatment significantly increased grain yield, yield components, harvest index, grain N and P, soil available P, root colonization percentage and crop WUE under water deficit stress. In some of investigated characteristics under well-watered conditions, chemical fertilizer treatment was higher than double inoculated treatments, but this difference was not significant. Seed inoculation only with AM positively affected the measured parameters as amount as co-inoculated treatments. According to the results showed in contrast to the inoculated treatments with AM+Pf and AM, the application of alone Pf caused a comparatively poor response. Therefore, this microorganism needs to a complement for its activity in soil. All of measured parameters in inoculated treatments were higher than uninoculated treatments under water deficit stress conditions. Furthermore, the investigated characteristics of co-inoculated plants under severe water deficit stress conditions were significantly lower than co-inoculated plants under well-watered and moderate-stressed conditions. Therefore it could be stated, these microorganisms need more time to fix and establishing themselves in soil. The present finding showed that phosphate-solubilizing microorganisms can interact positively in promoting plant growth as well as P uptake of maize plants, leading to plant tolerance improving under water deficit stress conditions.

Grazing affects essential oil compositions of Artemisia sieberi Besser.

This study was conducted in order to study the effect of grazing on quality and quantity of Artemisia sieberi essential oil in Kerman province of Iran. Vegetation sites of Artemisia sieberi under three grazing intensity (heavy, moderate and non-grazed) with the same ecological conditions were selected based on distance of water resource and nomad tent in Khabre National Park and near rangelands. Within each sits, two individual plants sampled at random in full flowering stage. The oils were obtained by hydrodistillation of air-dried samples and were analyzed by GC-MS. The main constituents of oils were as follows: non-grazed site; 1,8cineol (29.9%), myrcene (14.1%), moderate grazed site; myrcene (15.9%), 1,8cineol (15.1%), Eudesm-7(11)-en-4-ol (11.1%) and heavy grazed site; 4-tepinyl acetate (23.3%), davanone (21.9%), p-cymene (19%).