Effects of different salt concentrations and pH conditions on growth of Pennisetum clandestinum Hochst (kikuyu grass)

The effects of different salt concentrations and acidity on the growth of Pennisetum clandestinum, a perennial wild grass native to Kenya were tested to verify its adaptability to stress conditions and its possible use on Southern Italian soils. The root growth, the biomass and the activities of glutamine synthetase (GS), glutamate synthetase (GOGAT), glutamate dehydrogenase (GDH), phosphoenolpyruvate carboxylase (PEPC), and malate dehydrogenase (MDH), the key enzymes involved in ammonium and carbon metabolism, were tested. The data obtained showed that Kikuyu grass grew well in nutrient solutions with 50 and 100 mM NaCl or nutrient solutions with pH values of 4 and 5. But very high salt concentration and very low acidity reduced the plant growth. The enzyme activities of GS, GOGAT and PEPC were decreased when the grasses were treated with a salt concentration of 200 mM or grown in a solution with pH 3. The GDH activities increased in leaves of Kikuyu grass grown with a salt concentration of 200 mM, but decreased in leaves of those grown at very low pH. The MDH activities increased in leaves and roots of Kikuyu grass grown at pH 3, but decreased in leaves of those treated with a 200 mM salt solution. In conclusion, Kikuyu grass has a wide adaptability to stress conditions, therefore, it is possible to use it to prevent soil erosion in Southern Italy or in other similar soils with unfavourable environmental conditions for other plant species.