Proline Accumulation in Response to Magnetic Fields in Date Palm (Phoe- nix dactylifera L.)

Proline accumulation is a common biochemical indicator for assessing environmental stress in plants. The objective of this study was to determine the effect of various doses of two types of magnetic fields on date palm (Phoenix dactylifera L. (cv. Khalas) seedlings based on proline accumulation. The first type involved static magnetic field (SMF) generated by an electromagnetic circuit set at 10, 50, and 100 mT for 30, 60, 120, 180, 240 and 360 min. The second type involved alternating magnetic field (AMF) generated by a magnetic resonance imaging (MRI) device set at 1.5 T for 1, 5, 10, and 15 min. Following exposure to radiation, the seedlings were grown in potting soil for 4 weeks after which proline analysis was conducted. The results showed a significant two-way interaction between SMF intensity and exposure duration. At the lowest intensity, 10 mT, proline concentration increased in response to longer exposure durations reaching a maximum at 240 min. Beyond this duration, reduction in proline concentration occurred. In contrast, at 50 and 100 mT, proline concentration decreased as the exposure duration was increased. AMF significantly reduced proline concentration after as short as a 1-min exposure. This study would facilitate investigations related to stress physiology and in vitro selection of date palm tissue culture.