Effect of Salinity Stress on Nutrient Uptake and Chlorophyll Content of Tropical Turfgrass Species (Report‪)‬

Introduction Salinity is one of the most important abiotic stresses that widely distributed in both irrigated and non-irrigated areas of the world (Ashraf et al, 2008; Kamal Uddin et al, 2009). Salinity imposes ion toxicities (e.g., Na and Cl), ionic imbalance and osmotic stress to the plants including soil permeability problems (Flowers, 1999; Ashraf et al., 2008). Salt tolerance in plants is generally associated with low uptake and accumulation of [Na.sup.+], which is mediated through the control of influx and/ or by active efflux from the cytoplasm to the vacuoles and also back to the growth medium (Jacoby, 1999). In addition to osmotic adjustment, genotypic differences in inorganic ions uptake under salinity have implications for maintaining adequate nutrition and for optimizing nutrients/elements related salinity tolerance mechanisms. Uptake of essential ions (both cations and anions) including [K.sup.+], [Ca.sup.2+], [Mg.sup.2+], N[H.sub.4.sup.+], and N[O.sub.3]- have been reported to be suppressed in various species by high levels of NaCl, especially in saline soil and irrigation water (Rubinigg et al., 2003). Plant biomass production depends on the accumulation of carbon products through photosynthesis, but elevated salinity can adversely affect photosynthesis (Muns and Termaat, 1986; Macler, 1988). Many attempts have been made to detect differences in salinity tolerance of crop species or cultivars by measuring the modification of composition and function of the photosynthetic apparatus, changes in chlorophyll concentration (Leidi et al., 1991; Lutts et al., 1996 Kaya et al., 2007; Shabala et al., 2005). So the study on nutrient uptake and chlorophyll content in tropical turfgrass under salinity stress may be helpful in breeding for the development of salt tolerant cultivars. Therefore, the current study is designed to address the aforesaid issues critically.