Effect of NaCl on Growth and Mineral Nutrition of Laurel (Laurus nobilis L.)

Laurel, Laurus nobilis L., is a strict endemic species of natural vegetation of the Mediterranean region which is known for its medicinal, aromatic, forestry, ornamental and culinary properties. This has resulted in the species becoming rare or threatened with risk of extinction in Tunisia. Many factors can affect the production of this valuable plant including salinity, which appears to be most important, mainly in coastal areas. The present work has been carried out to test this hypothesis. The effect of different concentrations of NaCl (0, 50, 100 and 150 mM) of irrigation water on growth, SPAD index, chlorophyll fluorescence and mineral content of laurel was studied. The experiment was carried out in Tunis, in the year 2013. The results revealed that increasing NaCl concentrations significantly reduced fresh and dry weight of certain organs of the plant, SPAD index and chlorophyll fluorescence compared with the control. Application of NaCl induced also an increase in Na, Cl, K, P and N contents in leaves while Ca content decreased with increasing salt stress. Based on the present results, it can be concluded that laurel is an intermediate salt sensitive shrub.