Enhanced nutrient uptake in salt-stressed Mentha piperita using magnetically treated water.

The improvement of the growth and quality of medicinal plants under stress is of significance, worldwide. The hypothesis was to alleviate salinity stress in Mentha piperita by enhancing nutrient uptake using magnetically treated water, which to our knowledge has not been previously investigated. The objective was to test the effects of magnetized water (using alternating magnetic fields) (main plots, M1-M4 representing control, 100, 200, and 300 mT, respectively), salinity (subplots, S1-S4 representing control, 40, 80, and 120 mM NaCl, respectively), and growth medium (sub-subplots, X1-X4 representing coco peat, palm, coco peat + perlite, and palm + perlite, respectively) on M. piperita nutrient uptake in the greenhouse. The M treatments, especially the 100 and 200 mT levels, significantly increased plant N (1.08%, S3M4X1), P (0.89%, S3M3X1), K (3.23%, S3M3X1), Ca (53.6 mg/kg, S4M4X4), and Mg (39.63 mg/kg, S3M3X2) concentrations (compared with control at 0.71, 0.49, 2.4, 26.63, 1.63) even at the highest level of salinity. Magnetically treated water also significantly enhanced plant Fe and Zn concentration to a maximum of 750 µg/kg (M4S3X1) and 94.67 µg/kg (S4M4X3), under salinity stress, respectively. The single and the combined use of organic and mineral media significantly affected plant nutrient uptake, especially when used with the proper rate of M treatment. If combined with the proper growth medium, the magnetized water may be more effective on the alleviation of salt stress in Mentha piperita by enhancing nutrient uptake.

Pepermint (Mentha piperita L.) growth and biochemical properties affected by magnetized saline water.

Due to the limitation of suitable water for crop production in the world, recycling water is among the most proper methods enhancing water efficiency and availability. One modern method, which is of economic, health, and environmental significance, and may improve water properties for plant use is water magnetization. Medicinal plants are of nutritional, economic and medical values and their growth decreases under salinity stresses. This research was hypothesized and conducted because there is not any data, to our knowledge, on the use of magnetized salty water affecting the growth and biochemical properties of peppermint (Mentha piperita L.). The experiment was a split plot design with three replicates. The main plots consisted of magnetic fields at control (M1), 100 mT (M2), 200 mT (M3), and 300 mT (M4), the sub-plots consisted of salinity treatments (NaCl) at control (S1), 4 dS/m (S2), 8 dS/m (S3), and 12 dS/m (S4), and the growth media including cocopeat (X1), palm (X2), cocopeat + perlite (V/V = 50, X3) and palm + perlite (V/V = 50, X4) were located in the sub-sub-plots. Different plant growth and biochemical properties including plant fresh and dry weight, plant menthol, menthone, chlorophyll and proline contents were determined. Analysis of variance indicated the significant effects of experimental treatments and their interactions on the growth and biochemistry of peppermint. Different magnetic fields significantly increased plant growth, and interestingly with increasing the salinity level the alleviating effects of magnetic field on salinity stress became more clear (significant interaction between salinity and magnetic field treatments). Cocopeat was the most efficient growth medium. At the third level of salinity (8 dS/m) just the two levels of 100 and 200 mT increased plant menthol concentration. Treatments M3S2X4 and M1S1X1 resulted in the highest (38%) and the least menthol percentage (13%), respectively. Treatments S2 and M2 and M3 significantly increased plant menthone concentration, especially in the growth media of X1 and X3. However, at the third level of salinity, M3 and M4 were the most effective treatments. The highest (25.8%) and the least (1.2%) concentrations of menthone were related to treatments M3S2X4 and M2S4X1, respectively. The results indicated that it is possible to alleviate the stress of salinity on peppermint growth and improve its biochemical (medicinal) properties using magnetized salty water, although proline concentration was not much affected by the magnetic field.