Physiological Responses of Two Morinda Species under Saline Conditions

A pot experiment was conducted to investigate the effects of different salt concentrations on growth features, photosynthetic pigments and nutrient status in two species of Morinda: Morinda citrfolia and Morinda pubescens seedlings. Increased salinity had significantly altered the qualitative growth parameters measured in terms of height and average leaf area. It was also observed that the chl. a, chl. b and total chlorophylls decreased with increasing salinity treatments in leaves of M. pubescens while in leaves of M. citrifolia chl. a and total chlorophylls remains stable under saline conditions whereas chl. b exhibited increasing trend with increasing salt doses. The level of sodium content in leaves of M. citrifolia increased with increasing salinity treatment, the potassium content also increased with increasing salinity treatments in leaves of M. pubescens and M. citrifolia. The Ca content is significantly reduced at 200 and 300 mM NaCl concentrations in M. pubescens leaves. The growth, photosynthetic pigments and nutrient responses of Morinda to different salt stress conditions indicated that this species could resilient to salt availabilities at lower concentrations and adapt to salinity conditions very well.