the effect of foliar application of ascorbic acid and sodium nitroprusside on grain protein content, yield and some agronomic traits of safflower under water deficit stress

abstractbackground and purpose nowadays, the application of antioxidants and plant growth regulators has discussed for decreasing the negative effect of different stresses. ascorbic acid and sodium nitroprusside have substance caused witch the resistance to biotic and abiotic stresses. to evaluate the effect of ascorbic acid and sodium nitroprusside foliar application on some traits of safflower (carthamus tinctorius), a field experiment was carried out in split plot factorial based on randomized complete block design in university of shahrood.materials and methods two levels of irrigation, including 8 days interval (well watered) and 16 days interval (water deficit stress) were in main plot, and foliar application of sodium nitroprusside in 3 levels (0, 50 and 100 µm) and ascorbic acid in 3 levels (0, 10 and 20 mm) were in sub plots. stress treatment applied after plants establishment completely. the first foliar application of sodium niroprusside and ascorbic acid was performed in 63 and 65 days after sowing respectively and then repeat after 1 week. resultsresults showed that water stress decreased the capitol diameter, kernel weight, fertile capitol weight and number of seeds in capitol. ascorbic acid foliar application increased fertile capitol weight and capitol diameter. the number of infertile capitol decreased by ascorbic acid and sodium nitroprusside foliar application. ascorbic acid in 20 mm concentration increased significantly 0.69% in seed protein compared with control. the fertile capitol weight and capitol diameter increased significantly by sodium nitroprusside foliar application. seed protein increased by application 100 µm concentration. seed yield by application 100 µm sodium nitroprusside concentration was 13.2% more than control. the result showed that application 100 mm sodium nitroprusside concentration and 20 mm ascorbic acid concentration contained fertile capitol weight and increasing 35.1 percentage compared with control. conclusion20 mm ascorbic acid and 100 mm sodium nitroprusside concentration can introduced as the best treatment compound.keywords: ascorbate, drought stress, nitric oxide.resultsresults showed that water stress decreased the capitol diameter, kernel weight, fertile capitol weight and number of seeds in capitol. ascorbic acid foliar application increased fertile capitol weight and capitol diameter. the number of infertile capitol decreased by ascorbic acid and sodium nitroprusside foliar application. ascorbic acid in 20 mm concentration increased significantly 0.69% in seed protein compared with control. the fertile capitol weight and capitol diameter increased significantly by sodium nitroprusside foliar application. seed protein increased by application 100 µm concentration. seed yield by application 100 µm sodium nitroprusside concentration was 13.2% more than control. the result showed that application 100 mm sodium nitroprusside concentration and 20 mm ascorbic acid concentration contained fertile capitol weight and increasing 35.1 percentage compared with control. conclusion20 mm ascorbic acid and 100 mm sodium nitroprusside concentration can introduced as the best treatment compound.keywords: ascorbate, drought stress, nitric oxide.