Application of growth regulators plays important role under salt conditions. Perspectives to overcome these limitations by chitosan nanoparticle (CSNP: 0, 0.25, 0.5, and 1%) and pyridoxine (PN: 0, 0.03, 0.06, and 0.09%) seed priming was studied in both experiments with milk thistle seeds exposed to NaCl as salt stress (0, 50, 100, and 150 mM). Salinity threshold and EC50 (the salinity level that 50% of germination reduction) achieved 74.85 and 213.5 mM, respectively. A significant reduction in germination percentage (49.12%), seedling length (50.07%), and seedling vigor index (67.39%) while, a significant increase in superoxide dismutase activity (54.63%) were achieved at 150 mM NaCl in compared to the control treatment. The highest germination rate was resulted by 100 mM NaCl and 0.25% CSNP and the least (2.86 seed/day) by 150 mM NaCl and without CSNP. The salt stress significantly decreased photosynthetic pigments; however, the largest value of chlorophyll a, b, and total was related to without NaCl and 1% CSNP and the least value of traits (6.1, 1.67, and 7.77 µg/g FW) to non-application of CSNP under 150 mM NaCl. PN application was caused decrease in free proline content compared to the non-application treatment. The most pronounced effects of CSNP and PN were recorded in 0.25 and 0.09% concentrations, respectively. The finding of this study leads to the conclusion that seed priming with CSNP and PN by improving physiological mechanisms such as photosynthetic pigment synthesis, antioxidant enzyme activities, and free proline content increased salt tolerance in milk thistle seedling.

Zinc has an important role in plants survival under environmental stress conditions. Nano technology can be used in crop production to increase yield. In order to evaluate sunflower responses to Zno nanoparticle, an experiment was conducted in Agricultural Research Center of Islamic Azad University, Birjand branch, Iran. The experimental design was a split plot based on randomized complete block with three replications. Two irrigation treatments (full irrigation and 50% water requirement) were as main plots and 7 ZnO fertilizer levels (control, three bulk ZnO treatments and three nano ZnO treatments) were as sub plot. Water stress reduced significantly seed and biomass yield. All ZnO application treatments increased significantly seed yield mainly through increasing seed number per head. Harvest index was not significantly affected by irrigation and ZnO treatments. Deficit irrigation significantly increased seed and biomass WUE 43.6 and 40.2 percent, respectively. In full irrigation treatment the highest seed and biomass WUE were related to bulk ZnO treatments, but in water stress condition the highest biomass WUE was related to NZnO treatment. Totally the result indicated that application of nano ZnO increased seed yield and water use efficiency. 

Sorghum [Sorghum bicolor (L.) Moench] is among the most important warm-season forages that is grown in mainly arid and semiarid regions of southeastern Iran. Irrigation water is an energy-intensive input and it is also becoming scarce and costly in this country. Soil application of polymeric materials such as Superab A200 (SAP) can increase soil water storage capacity and increase water use effi ciency (WUE). Th e objective of this study was to investigate the eff ect of diff erent rates of SAP and irrigation regimes on dry matter yield, WUE, and some physiological and yield-related traits of Speedfeed sorghum. Th e experiment was conducted in Zahedan, Iran, during the 2009 and 2010 seasons under limited irrigation regimes (irrigation aft er 40, 60, 80, and 100% crop evapotranspiration = ET c ) and four rates of SAP application (0, 75, 150, and 225 kg ha -1 ). Results indicated signifi cant eff ects of irrigation regimes, SAP levels, and their interaction. Th e analysis for dry matter, WUE, and benefi t/cost ratio showed that applying SAP at 100% ET c had no eff ect on these traits, but in the treatments with water defi cit, it improved all the studied traits of sorghum. With regard to economic analysis, applying 75 kg ha -1 SAP for a decrease in the sorghum's water requirement of as much as 20% is economically justifi ed at moderate water defi cits.

Normally the productivity of cropping systems in arid and semi-arid regions is very low. The sustainable agricultural systems try to fi nd out environmental friendly technologies based on physical and biological treatments to increase crop production. In this study two irrigation treatments (control and water stress) and six methods of fertilizer treatment (control, NPK-F, using magnetic band-M, using silver nano particles-N, M+N and M+N+50% F) on performance of ajowan were compared. Results showed that treatments with magnetic fi eld or base fertilizer had more yield compared to the control and silver nanoparticles (N) treatments. Application of silver nanoparticles had no positive effect on yield. The highest seed and biomass WUE achieved in base fertilizer or magnetic fi eld treatments. Under water stress treatment, seed WUE signifi cantly increased. In conclusion magnetic fi eld exposure, probably by encourage nutrient uptake effi ciency could be applied to reduce fertilizer requirement. On the other hand the cultivation of plants under low MF could be an alternative way of WUE improving.

A common problem with vegetable production in drought areas is low crop stand, but germination data are limited and inconsistent for cumin. Different priming methods positively affect the enhancement of seed germination and seedlings growth, especially under stress conditions. The objective of this study was to assess the effects of different priming treatment (unprimed seeds as control, hydro-priming, salicylic acid, jasmonic acid, paclobutrazol, and chitosan) on cumin seed germination indices and physiological traits under osmotic stress (0, -5, and -10 bar; induced by polyethylene glycol-6000). Seed germination of cumin was reduced by 9.77% and 23.95% under osmotic potential -5 and -10 bar, respectively, compared with non-stressed conditions. Nevertheless, priming enhanced germination indices and improved photosynthetic pigments and activity of peroxidase, catalase, and superoxide dismutase enzymes at all potential osmotic levels compared with non-primed seeds. Seed treated by jasmonic acid showed the highest seedling vigor index and chlorophyll and carotenoids content under stress and non-stress conditions. Under the high level of osmotic potential (-10 bar), jasmonic acid treatment was caused increasing by 59.3%, 55.19%, 54.26%, 57.52%, and 47.72% of seedling vigor index, total chlorophyll, chlorophyll a, b, and carotenoids content, respectively. In conclusion, the jasmonic acid priming can modify the negative effects of the osmotic stress by improved physiological traits resulting in enhanced germination parameters.