فاطمه سادات مسلمی

The use of salt tolerant plants in arid and semi-arid regions of the world, including Iran, is one of the ways to achieve high yields. The aim of this study was to investigate the effect of different salinity treatments in hydroponic culture on physiological characteristics, phenylalanine-ammonialyase (PAL) activity and also the small amount of flavonoid compounds kaepmferol and quercetin in field saffron (Crocus sativus L.). For this purpose, saffron corms were planted in pots containing perlite and irrigated in controlled laboratory conditions with ½ Hoagland nutrient solutions containing concentrations of 0, 30, 60, 90, 120 and 150 mM sodium chloride. Based on the obtained results, the effect of salinity stress was not significant on chlorophyll a and b levels at 5% level. Carotenoids and glucose levels in the 60 mM treatment had a significant increase of 27% and 56%, respectively, compared to the control treatment. The effect of salinity on leaf amino acid proline was not significant..The relative water content (RWC) in 150 mM with a decrease of 20%, had the highest decrease compared to the control treatment. The activity of PAL enzyme in only 150 mM had a significant increase of 50%. The amount of kaempferol in all concentrations except 150 mM and the amount of quercetin in only 150 mM showed a significant increase (100%) compared to the control treatment. It seems that according to the test results, the tolerance threshold of saffron plant to salt is in the range of 60 to 90 mM and the defense mechanisms mentioned in this range and above help the plant to tolerate salt.

In order to investigate the effect of salinity stress on the amount of two important metabolites of saffron (Crocin) and Picrocrocin (Flavor Factor), saffron corms were planted in hydroponic conditions in pots containing perlite and in controlled laboratory conditions with 100 ml of ½ Hoagland nutrient solution containing 0, 30, 60, 90, 120 and 150 mM Sodium chloride (NaCl) were irrigated for four weeks. After flowering, stigmas were harvested and crocin and picrocrocin were separated and purified by high performance liquid chromatography (HPLC) equipped with detector spectrophotometer (HPLC-DAD). The results showed a significant difference in the amount of crocin between different salinity treatments at 5% level, the highest decrease in crocin content was observed at 120 mM NaCl, which was 98% lower than the control treatment. There was no significant difference in picrocrocin in different treatments, but in the 90 and 120 treatments, there was a significant decrease of 45% and 41%, respectively. According to the results of the present study, salinity decreased the secondary metabolites of saffron.