Influence of different intensities of magnetic field on germination, vegetative growth and some physiological aspects of salinity- stressed cucumber By Ali H Ibrahim Assistant Prof., Botany Dept., Faculty of Science At Al-Arish, Suez Canal Univ. 1

The presentation will include: 1-INTRODUCTION 2-MATERIALS & METHODS 3-MAIN RESULTS & INTERPRETATION 4-CONCLUSION 2 Outline Of The Presentation

1- INTRODUCTION 3

INT. Salinity is one of the major environmental factors limiting worldwide productivity and distribution of crops in agriculture (PARIDA and DAS, 2005). One way to overcome the problem of salinity is by exogenous application of advanced chemicals such as plant growth regulators. The negative impact of these chemicals on the environment has led the agricultural scientists to explore the influence of physical factors such as magnetic fields on plants (TANVIR et al., 2012; BILALIS et al., 2013). The literature survey reveals that most studies have been concerned with the interactive effect of magnetic field and salinity stress on plants during the 4

germination stage ( CAKMAK et al., 2010; THOMAS et al., 2013). L ittle researches have been carried out to explore this dual effect at vegetative growth and late growth stages. Cucumber was selected for this study due to its sensitivity to salinity, whereas its growth can be reduced by an irrigation water with an EC higher than 1.2 dS/m (CHARTZOULAKIS, 1992). Furthermore, no information is available about the effect of seed magnetization on cucumber vegetative growth.  Objectives of the study: To investigate the influence of different intensities of magnetic field on seed germination, vegetative growth, membranes stability and some biochemical aspects of cucumber grown in salinity stress conditions. 5

2- MATERIALS & METHODS 6

 Seeds material Seeds of cucumber (Cucumis sativus L. var. Beit Alpha) were used.  Magnetic field treatments  Seeds sterilization.  Seeds soaking.  Seeds packing in a cylinder of filter paper.  Seeds exposure to different magnetic fields using the dia, para and ferromagnetism apparatus (0.0 mT, 50 mT, 100 mT and 200 mT, at 30 seconds and 1/2 hour exposure time). 7

Fig.1. Dia, para and ferromagnetism apparatus 8

 Germination experiment (for 5 days)  Experimental treatments (14 treatments) 9 Exposure period Magnetic intensity mT)) Salinity level s, ½ h s, ½ h s, ½ h % seawater 30 s, ½ h5010 % seawater 30 s, ½ h10010 % seawater 30 s, ½ h20010 % seawater

 Measured parameters 1-Germination percentage. 2-Seedlings biomass and vigour. Vigour index = Germination % × Seedling length 3-Assay of amylase Starch–Iodine method with UV-Vis spectrophometer. 4- Peroxidase activity. Spectrophotometerically by guaiacol oxidation method 5- Total RNA RNA in the samples was purified by silica-gel column (SGC)-based isolation technology at FARP and measured by UV spectrophotometer. 10

Follow up Measured parameters in germination stage : 6- Total protein Digestion, distillation and titration for total N determination at FARP. 7- Metallic ions Na and K by flame photometer. Fe by atomic absorption spectrophotometer 8-Total soluble sugars Spectrophotometrically by the anthrone method. 11

 Vegetative growth experiment  Growth conditions Pot experiment for 5 weeks where the plants subjected to day night natural condition. Half of pots were irrigated with 10% seawater.  Measured parameters 1-Shoot biomass. 2- photosynthetic pigments. 3- Membranes electrolytes leakage. Based on measurement of electrical conductivity of leaves ( initial EC initial, first EC and total EC).  Statistical analysis SPSS version 15 software. 12

3-RESULTS & Discussion 13

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mT 50 mT 30s 50 mT 1/2h 100 mT 30s 100 mT 1/2h 200 mT 30s 200 mT 1/2h 0.0 mT 50 mT 30s 50 mT 1/2h 100 mT 30s 100 mT ½ h 200 mT 30 s 200 mT ½ h Controls Salinity stress

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4- CONCLUSION 24

Conclusion 1-The effect of magnetic field on cucumber depends on magnetic intensity and exposure period. 2- The optimum doses to mitigate the adverse effect of salinity stress on the used variety in germination and vegetative stages is 50 mT for 1/2 h and 100 mT for 30 sec. 3- The enhancement effect of 50 mT for 30 seconds appeared in the vegetative stage only. 4- The promotive effect of these magnetic treatments was attributed mainly to the enhancement in total RNA, soluble sugars, amylase activity and total chlorophylls, and reduction in the electrolyte leakage. 5- High magnetic doses e.g. 200 mT for 1/2 h had a negative impact on cucumber. 25

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