PJB-2017-881
SALINITY AND WATER DEFICIT EFFECTS ON SEED GERMINATION AND RECOVERY OF Lotus POPULATIONS COLLECTED IN NORTHERN TUNISIA
RIM HAJRI
Abstract
Trials were set to assess salinity and water deficit effects on seed germination and recovery of populations of Lotus creticus L. and Lotus ornithopodioides L. species collected from different bioclimatic regions in northern Tunisia. Salinity treatments were 0, 50, 100, 150, 200 and 250 mM of NaCl. Water deficits of 0, -0.2, -0.6, -0.8 and 1.0 MPa were induced using polyethylene glycol 8000 (PEG-8000). Seeds of L. creticus L. species collected from Tabarka region weighted 3.39 g/1000 seeds compared to less than half of this weight for all other Lotus populations with no effect on seeds germination capacity. Lotus creticus L. seeds collected from Seddine region showed 80% germination at 250 mM of NaCl compared to 55.7% for Tabarka populations. Seed germination of L. ornithopodioides L. was not affected by salinity regardless of population provenance indicating species tolerance to salinity. At -0.4 MPa water potential deficit, seed germination of L. creticus L. collected from Seddine region was reduced by 14% compared to 48.5% reduction for seeds from Tabarka provenance which can indicate its tolerance to water stress. Lotus ornithopodioides L. seed germination was reduced by 47% at -0.2 MPa and almost inhibited at -0.6 MPa water potential indicating species low tolerance to water stress. Lotus species ungerminated seeds under salinity and PEG-8000 induced water deficit treatments recovered their germination capacity when transferred to distilled water regardless of species and provenances.
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