Root-released organic acids and phosphorus uptake of two barley cultivars in laboratory and field experiments.

摘要

After cultivation in nutrient solution for 21 days, barley cv. Marinka produced more root dry matter than Sonate, but similar amounts of shoot dry matter. However, the shoot dry matter of Marinka had a lower P content than that of Sonate. The totalP uptake per plant did not differ between the cultivars. Marinka retained more P in roots. In sterile nutrient solution culture, the cultivars differed mainly in release of organic acids from the roots, with Marinka releasing 3 times more citric acid andnearly 2 times more acetic acid than Sonate. The cultivars had similar root hair lengths and they did not differ in depletion of available soil P fraction in the rhizosphere. Marinka absorbed nearly twice as much P from the strongly adsorbed soil P fraction as Sonate. Under field conditions, Marinka absorbed more P and produced more shoot dry matter. The higher P uptake by Marinka than Sonate can be attributed to its ability to acquire P from strongly adsorbed soil P by releasing more organic acids, especially citric acid, from its roots.