Abstract
Energy dispersive X-ray microanalyzer (EDX) is efficient for individual selection of high-Mg plants by using ashed samples. Ashed sample preparation is time and labor intensive. This experiment was initiated for introducing X-ray microanalysis of fresh leaf tissues for individual selection and thus expedite the term necessary for sample preparation as well as individual selection. The approach was justified by using two tall fescue populations, HiMag and Kentucky 31 (Ky-31), having known differences in Mg contents. Plants were evaluated for mineral contents by energy reflectance X-ray fluorescence(ERF) analyzer and for relative densities of minerals in fresh leaf tissues (epidermis, fiber, mesophyll, phloem, vascular bundle sheath, xylem) by EDX analyzer. HiMag tall fescue showed higher Mg and Ca contents while lower K content than Ky-31 tall fescue. This trend was consistent for relative densities of minerals in different tissues of the cultivars. Among the tissues, mineral densities in xylem showed better correlations with whole plant mineral contents. Plants selected according to the higher Mg densities in xylem tissue had high Mg and Ca contents while low K contents, which indicates the high-Mg plants. This suggests the applicability of using relative density of minerals in xylem tissue for individual selection of high-Mg plants.
