Root surface phosphatase activity in ecotypes of Aegilops peregrina

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Abstract
The relationships between root surface phosphatase activity and the edaphic factors of their native habitats were investigated in four ecotypes of Aegilops peregrina (Hack.) Maire et Weil. In one set of experiments plants were grown in phosphate‐deficient nutrient solution cultures (5 μM) with three pH values: 5.5, 6.5 and 7.5. In a second series, plants were grown in both P‐poor and P‐rich soils.Results showed an optimal activity of the commonly‐described root surface acid phosphatase of pH 4.5–5.0 in the ecotypes Meron (a P‐poor montmorillonitic, typical mediterranean Terra‐Rossa soil) and Har‐Hurshan (a P‐rich calcareous soil). However, in the ecotypes Malkiya (a P‐rich kaolinitic Terra‐Rossa) and Bet‐Guvrin (a P‐rich calcareous soil) the optimal activity of the phosphatase occurred at pH 6.0. The pH level of the growth solution had no effect on the pH of optimal activity of the phosphatase in the ecotypes Malkiya and Bet‐Guvrin, but it somewhat affected their level of activity.Phosphatase activity was stimulated when plant roots were grown in a P‐poor soil, as compared to the activity of those which were grown in a P‐rich soil. Plants of the Malkiya ecotype exhibited the strongest activation of phosphatase as compared to the other three ecotypes. It seems that ecotypes which have evolved in P‐rich soils may regulate their root surface phosphatase activity better than those which have evolved in P‐poor soils.