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To evaluate the effects of nitrogen and water stress on allelopathic potential of sorghum (Sorghum bicolor) on the seed germination traits of safflower (Carthamus tinctorius), a factorial experiment was carried out in randomized complete design (CRD) with three replications in the greenhouse and laboratory, College of Agriculture, Shiraz University, Shiraz, Iran in 2012-13. Treatments included irrigation [Normal (I1) and water stress (I2)] and nitrogen [control (no nitrogen), Urea (200 kg N ha-1), Nitroxin (Azotobacter) and Nitrokara (Azospirillum and Azotobacter) inoculation per kg seeds]. Extracts were prepared from sorghum shoot resiude in 5, 10, 15 and 20 (W/V) and were applied to individual Petri dishes distilled water was used as control treatment. Also, foliar applications of extracts were applied in treatments under the greenhouse conditions and sorghum dried residues were also mixed with the soil in amounts of 0, 5, 10, 15, and 20 g after the first irrigation. Analysis of variance showed that interaction effects of sorghum extract type and its concentration had significant effects on all traits except relative water content. Safflower germination percentage reduced with increase in concentration. 5, 10 and 15% concentrations of Nitrokara under normal irrigation had 34, 22 and 12%, effects on allelopathy index of safflower respectively. Whereas concentration of 20% extract, decreased allelopathy index by 71%. The effects antagonist on length and dry weights of roots and shoots was observed when biofertilizer treatments (Nitroxin and Nitrokara) applied. In addition, more synergist effects were obtained when urea extract was appliedt under water stress. The results of foliar application revealed a decrease in CAT and POD activities in leaves of safflower when urea was usedunder water stress conditions. However, the lowest germination rate and primary growth of safflower was abserved when urea applied under water stress conditions.

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In order to evaluate the effect of different levels of defoliation and grain removal on grain yield and photosynthesis rate of sunflower, a factorial experiment was conducted based on randomized complete block design with three replications during 2012 growing season at College of Agriculture, Shiraz University. Treatments were defoliation at 3 levels (0, 50, and 75%) in heading stage and grain removal (without grain removal (control), removal of one half of the grains in inner or side parts) at pollination stage. It appeared that defoliation resulted in reduction of grain yield, 1000 grain weight and grain number. Apparently increased photosynthetic rates of reminder leaves may be considered a response to the reduction of leaf area however it did not generally sufficient to compensate the reduction of leaf area. The highest reduction of grain yield was recorded in 75% defoliation and removal of one-half of the grains in inner parts of head, compared to control. It can be concluded that grain yield of sunflower is more determined by limited source.

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Most crops are sensitive to salt stress, however, this sensitivity was differ in different growth stages. In current research, the effect of varied salt stress levels (0.4, 4, 7 and 10 dS m^-1) in different growth stages (5 leaf, stem elongation and flowering) was examined on morpho-physiological, and content of sodium and potassium in rape seed Sarigol cultivar in a controlled experiment based on a completely randomized design with three replications at College of Agriculture, Shiraz University in 2014. Salt stressed plants had the lowest amount of plant height (27%), leaf number (30%), leaf area (31%), shoot (45%) and root dry weight (40%) and shoot (47%), and root K⁺ concentrations (54%) and had the greatest amount of chlorophyll content index (20%) and shoot (5 flod) and root Na⁺ (1.8 flod) concentrations; which this change was intensified by increasing in salinity level. Salt stress changed sodium distribution, so that in saline conditions shoot/root Na⁺ was significantly more than non-saline conditions. With the delay in stress applying, the negative effect of salinity was reduced; 10 dS m^-1 salinity at 5 leaves and flowering were respectively associated with 78.8 and 30.2 percent reductions in shoot dry weight and with 68.6 and 26.7 percent reduction in root dry weight, compared to control. Although salt stress at 5 leaves had more and at flowering had less impact; however, increasing in stress level in all three stages intensified negative effects of salinity. If the current results were confirmed in complementary and long term researches, rape seed could be irrigated with relative saline water at late of the growing season under limited fresh water regions.