Salinity tolerance traits in three grass species:Potential selection criteria for varieties for future sustainable farming

In this thesis, we tested Puccinellia maritima as a model forage grasses under saline conditions in comparison with two other grass species Festuca rubra and Lolium perenne. We compared different cultivation substrates under salt treatment with harvest for mimic cutting regime. The results demonstrate that, under simulated grazing or cutting conditions, P. maritima is the superior salinity tolerant specie, under even high salt conditions. During short term and long-term salinity, P. maritima maintain a high photosynthetic electron transport rate and maximum photosynthetic efficiency (Fv/Fm). The root system architecture (RSA) of P. maritima responds very differently from the other two. P. maritima increases the seminal root length under moderate salinity. The root surface ion flux under salt and salt addition varies in ion transportation. A moderate salinity addition (50 mM NaCl) fails to induce P. maritima loss of H and K. The higher salt of 100 mM induces quite less K flux in P. maritima than L. perenne and F. rubra, and the salt shock recovered fast within 5 min to a stable status. Meanwhile, we isolated endophytes from salt marsh F. rubra and inserted to the commercial F. rubra, leading to shoot growth and decreasing of the K+ loss. This experiment highlights that not only the halophyte plant itself but also endophytic fungi are important. In breeding programs, these different traits could be exploited, within subspecies as they are examples associated with (temporary) reduced above ground productivity