High magnesium concentration in serpentine soils does not affect the

Serpentine soils have some unusual properties such as low Ca and high Mg concentrations and also some of the heavy metals which are the inducers of high plant endemism. One of the possible causes of endemism could be Ca sensitivity and high Mg requirement. Since Mg and Ca interact in uptake and transport by plants, the effect of Mg in Ca sensitivity was studied in Alyssum inflatum which is a serpentine endemic from western Iran and its Ca sensitivity has proved. The seeds were harvested from thier natural habitats and the plants were cultivated in greenhouse using of a solution culture on chemically inert substrate of Perlite. A modified one forth strength Hoagland solution was used and different concentrations of Ca and Mg were achieved. To determine the viability of plants, the appearance of plants including wilting and drying of the shoot, and root cell death were determined using of Evan’s blue staining. The results showed that the plants were sensitive to high concentrations of both of cations of Ca and Mg. Effect of Ca/Mg ratios on survival of plants was important provided that the absolute concentrations of the elements were low. The results suggested that one of the endemism reasons on serpentine soils was Ca sensitivity while high Mg concentrations did not decrease the sensitivity.