Interactive effect of salinity and zinc stress on growth and photosynthetic responses of the perennial grass, Polypogon monspeliensis

A glasshouse experiment was designed to investigate the interactive effect of zinc from 0 to 300 ppm and/or 150 mM NaCl on the growth and the photosynthetic apparatus of Polypogon monspeliensis from two Tunisian provenances (North and South) seedlings by measuring Growth, photosynthesis, chlorophyll fluorescence and chlorophyll concentration after 30 days of treatments. These parameters were severely reduced by this heavy metal. The zinc excess involves the degradation of photosystem II and the chlorophyll decomposition. However, these effect of Zn concentrations alleviated by 150 mM of NaCl. Adequate Zn also prevents uptake and accumulation of Na and Cl− in shoot, by increasing membrane integrity of root cells. Our results show that at the same time, the variation of these parameters depends on the seeds origin, Zn stress and saline conditions.