Alleviation of Adverse Effects of Seawater on Growth and Chemical Constituents of Chrysanthemum morifolium by Foliar Fe and Mn Applications

摘要

Chrysanthemum morifolium plants were grown in a pot experiment to investigate the effects of seawater stress using 0, 2, 4 and 8% seawater (SO, S2, S4 and S8, respectively). The plants grown in sandy soil were foliar-sprayed three times with 5 ppm ofMn and/or Fe in addition to the standard fertilizer applied to the soil. The seawater-stressed treatments had a shorter plant height, lower plant Fresh Mass (FM) and Dry Mass (DM), lower flower head fresh mass and smaller flower diameter than the plantsthat were not exposed to seawater. These reductions correlated with the seawater concentration and the foliar applications significantly alleviated these adverse effects. The plants watered with S8 and treated with Mn+Fe had a higher FM (446.4) and DM (25.4 g plant-1) than the SO-watered plants not treated with the foliar fertilizers (404.9 and 17.4 g plant-1), whereas the flower head fresh masses were 96.3 and 108 g plant-1, respectively. Increasing the concentration of seawater from SO to S8 reduced the onset of flowering from 105 to 94 days and the foliar treatment significantly delayed the flowering date, regardless of the type of irrigation water. The S8-watered plants treated with Mn+Fe had significantly higher levels of chlorophylls a and b andcarotenoids than the SO-watered plants sprayed with tap water. Furthermore, the Mn and/or Fe-mediated alleviation of seawater stress in the chrysanthemum plants was associated with higher levels of proline as well as reducing and non-reducing sugars. Inconclusion, overall, the results support the hypothesis that foliar Fe and Mn treatment can alleviate seawater stress in chrysanthemum plants.