Evaluation of changes in fatty acid profile, grain, and oil yield of Carthamus tinctorius L. in response to foliar application of polyamine compounds under deficit irrigation conditions

Safflower is an oilseed plant rich source of omega 3 and 6 whose fatty acids composition may be affected by water deficit stress. Thus, filed experiments were conducted in Tehran, Iran during 2017 and 2018 growing seasons to investigate the influence of foliar application polyamines on fatty acid compositions and agronomic traits under deficit irrigation stress as a split plot with four replications. The studied treatments included irrigation at two levels of normal irrigation (I1, 50 %) and deficit irrigation at flowering stage (12, 75 %) (irrigation after depletion of 50 % and 75 % moisture of field capacity, respectively) as the main plot and foliar application treatments at 10 levels included (water foliar application or control, foliar application putrescine, spermidine and spermine each in concentrations (50, 100, 200 mu mol L-1)) as the subplot. Foliar application of putrescine under 12 enhanced grain and oil yield by 721.7 and 120.7 kg ha(-1), respectively, on average in the two years of experiment compared with the control treatment. The total polyunsaturated and unsaturated fatty acids (Sigma PLIFA and Sigma UFA), UFA (omega 3 and 6), ratio of Sigma PUFA to saturated fatty acids (Sigma SFA), harvest index and oil content rose under 12 conditions in both years of the experiment with spermine foliar application. Foliar application of putrescine also increased omega 6, Sigma PUFA and Sigma UFA under I1 conditions in both years. The results of this experiment indicate that foliar application of polyamines can improve grain and oil yield and quality of fatty acids of safflower under irrigation regimes.

Automated summary

The study indicates that foliar application of polyamines can improve grain and oil yield as well as the quality of fatty acids in safflower crops under water deficit stress, especially with putrescine application during the flowering stage.