Abstract
Three cultivars, including one high-Mg and two commercial cultivars from each of Italian ryegrass, orchardgrass and tall fescue grown under solution culture condition were evaluated for minerals, viz., magnesium (Mg), calcium (Ca), and potassium (K) density by X-ray microanalysis. Three K treatments of 1.0, 5.0 and 25.0mM were superimposed on one-month aged seedlings for 10 days. Increasing solution K concentrations resulted an increase in shoot dry weight of the cultivars. All the high-Mg cultivars of three species showed higher Mg and Ca, and lower K density irrespective of K treatments. These high-Mg cultivars showed significantly higher Mg density in 5.0mM solution K level irrespective of species and experiments. Among the K treatments, cultivars of different species showed highest Mg density in 5.0mM solution K level. Increase or decrease in solution K levels from 5.0mM in the growing medium resulted a decrease in Mg density. There was no difference for Ca density between 1.0 and 5.0mM solution K levels while lowest Ca density was observed in 25.0mM solution K level. There was an increase in K density with increasing solution K concentrations. Consistent trend among the high-Mg cultivars of the three species for higher Mg density in 5.0mM solution K level within the species and experiments, suggests that while using X-ray microanalysis, 5.0mM level of K under solution culture condition is the best for screening plants with higher Mg density.
