Influence of hydrogel polymer and NO3-: NH4+ ratios on dill (Anethum graveolens L.) seed essential oil composition and yield Journal Article

To evaluate the effects of hydrogel polymer levels (0, 10, 20, 30 g m-2) and NO3:NH4 ratios (0: 100, 25: 75, 50: 50, 75: 25, and 100: 0) on dill seed yield and its essential oil constituents, an experiment was conducted in October 2012 in the experimental field of Islamic Azad University, Jiroft, Iran. Results showed that using 30 g m-2 hydrogel polymer with 75NO3-: 25 NH4+ ratio produced maximum seed yield and the same plus 100NO3-:0NH4+ led to a max essential oil yield. GC-MS analysis indicated that major constituents of dill seed oil were carvone, limonene, dillapiole, α-phellandrene, and trans-dihydrocarvone. The interactive effects of concurrent use of hydrogel polymer and NO3-:NH4+ ratios on the constituents were evaluated: non-use of super-absorbent polymer reduced components like α-terpinene, limonene, dillapiol, and trans-carvone, whereas its addition to such compounds as α-phellandrene, p-cymene, carvone, and trans-dihydrocarvone left a negative effect. In most cases, application of nitrate above 50℅ and reducing ammonium positively increased the compounds

"Salarib a Soil Science Department, Vali-e-Asr Rafsanjan University of Rafsanjan, Rafsanjan, Iran b Islamic Azad University of Jiroft, Jiroft, Iran Received: 14 November 2015; Received in revised form: 13 March 2016; Accepted: 4 May 2016 Abstract To evaluate the effects of hydrogel polymer levels (0, 10, 20, 30 g m-2) and NO3:NH4 ratios (0: 100, 25: 75, 50: 50, 75:25, and 100: 0) on dill seed yield and its essential oil constituents, an experiment was conducted in October 2012 in the experimental field of Islamic Azad University, Jiroft, Iran. The interactive effects of concurrent use of hydrogel polymer and NO3-:NH4+ ratios on the constituents were evaluated: non-use of super-absorbent polymer reduced components like α-terpinene, limonene, dillapiol, and trans-carvone, whereas its addition to such compounds as α-phellandrene, p-cymene, carvone, and trans-dihydrocarvone left a negative effect. In addition, the interactive effect of the simultaneous use of various nitrate to ammonium ratios and superabsorbent polymers considerably affected the dill seed essential oil (Figure 2). The evaluation of the interactive effects of the concurrent application of N forms and hydrogel polymer on dill essential oil compounds showed that use of the superabsorbent polymer raised α-terpinene, limonene, dillapiol, and trans-carvone, whereas adding this polymer to α-phellandrene, p-cymene, carvone and trans- dihydrocarvone affected the essential oil composition negatively. Moreover, the significance of the interactive effect of nitrate to ammonium ratio and super-absorbent polymer on dill seed yield and yield components signifies the super-absorbent role in absorbing and conserving water for the plant, leading to an increase in dill yield and yield components."