Mineral element concentration of two barley cultivars in relation to water deficit and aluminum toxicity

Abstract

Abstract The separate and combined effects of water and Al stress on concentrations of P, K, Ca, Mg, Fe, Mn, Zn, Cu, B, Al, Sr, and Ba were determined in tops of ‘Dayton’ (Al‐tolerant) and ‘Kearney’ (Al‐sensitive) barley (Hordeum vulgäre L.) grown in an acid, Al‐toxic, Tatum subsoil (clayey, mixed, thermic, Typic Hapludult). Plants were grown 4 weeks in a plant growth chamber at high (pH 4.7) or low (pH 6.6) Al stress. During the last 2 weeks they were also subjected to low (‐20 to ‐40 kPa), moderate (‐40 to ‐60 kPa), or high (‐60 to ‐80 kPa) water stress. In general, Al stress had a greater overall effect on mineral element concentration of tops than water stress. Aluminum stress significantly decreased concentrations of P, Ca, and Mg and increased concentrations of Zn, Sr, and Ba, irrespective of the cultivar or water stress treatment. Cultivar differences in Mn concentration were observed with Al stress under all water stress conditions. In each case, Mn concentration was lower in ‘Kearney’ than in ‘Dayton’. Potassium, Ca, and Mg were lower in ‘Kearney’ than in ‘Dayton’ only at low and moderate water stress, under low Al stress, ‘Kearney’ had significantly higher concentrations of K and Ca than did ‘Dayton’ under all water stress conditions. The effects of water stress on mineral element concentration varied greatly with cultivar, Al stress treatment, and severity of water stress. Under high Al stress, increasing drought conditions from low water stress (‐20 to ‐40 kPa) to high water stress (‐60 to ‐80 kPa) significantly increased the concentrations of Ca, K, Zn, Sr, and Ba in Al‐sensitive ‘Kearney’ and reduced the concentrations of Zn, Sr, and Ba in Al‐tolerant ‘Dayton'; P and Mg concentration were unaffected by water stress. In contrast, under low Al stress, a corresponding increase in water stress significantly increased the concentrations of Ca and reduced that of P in ‘Kearney’ and increased Ca and B concentration in ‘Dayton'; Mg concentrations were unaffected in either cultivar. Thus, it appears that Al stress and water stress had opposite effects on Ca accumulation in barley tissue.