Analysis of magnetic salinity water irrigation promoting growth and photosynthetic characterisitcs of Populus×euramericanna 'Neva'

Abstract: The salt stress could injury the photosynthetic mechanism and affect the photosynthetic function of plants. To explore the action of salt stress on plants growth under magnetic treatments (M4,M0 Ms), and to understand the magnetized effect on reducing salt injury, parameters such as different morphological parameters, photosynthesis and the chlorophyll fluorescence parameters, were measured. Some experimental materials, from one-year cutting seedlings of salt-sensitive Populus × euramericanna 'Neva', were irrigated with magnetized 0, 4.0 g/L NaCl solution, others were irrigated with the same solution but non-magnetized (NM0,NM4 NMs). The results showed that: 1) Pn, Gs, Ci, Tr, WUE decreased 1.5%-51.1% in NM4, and M4, Ls increased 12.2% and 26.7% respectively. There were extremely significant differences for them compared to NM0 and M0; the NM0 and M0 maintained higher but Ls lower than that of NMs. They respectively characterized by significant difference among the treatments (P<0.01). 2) ΦEo, Fv/Fm, and PIABS, first increased and then decreased with prolonging of stress time, showed same trend. Compared with NM0 and M0, the treatments in different group showed extremely significant difference (P<0.01); the Ms kept a relatively higher level compared to NMs, and the increasing proportion was within 0.12%-18.2%. 3) Compared with the control treatments (NM0, M0), the salt-stressed treatments decreased in the height, branch diameter, single leaf area, biomass parameters, root, and leaf biomass allocation proportions, with the increasing extent of 10.7%-55.8% for these parameters. The stem biomass, increasing from 15.8% to 20.9%, had extremely significant differences among the four groups (P<0.01). The Ms also kept a relatively higher level among those 6 biomass indexes compared to NMs. 4) The morphological parameters of root system declined, by 12.8%-51.5% in salinity treatments, but Ms kept higher than NMs, and there were extremely significant difference for the overall level of performances (P<0.01). Salt in soil could reduce the root/shoot ratio, root diameter, length, area and volume, which maintained higher levels of root morphological parameters in Ms respectively. There were extremely significant differences except the root volume compared with NM0 and M0 (P<0.01). In conclusions, the salt injury to photosynthetic mechanism of plants in Ms was less than in NMs which was beneficial to maintaining the integrity of the photosynthetic organ function, and thus-increasing physiological and biochemical activities in plants and promoting its growth.