Accumulation of some essential nutrients by lentil (Lens culinaris) plants at low potassium regimes

The effect of low K+ regimes on a salt-tolerant line ILL 6796 and a salt-sensitive line ILL 6439 of lentil (Lens culinaris) was studied in a pot experiment in glasshouse conditions. Plants of the two lines were treated with 78, 39, 19.5, and 9.75 mg K+ L(-1) in the Rorison's nutrient solution. The salt-tolerant line had a higher content of shoot dry matter at the lowest external K+ concentration than the salt-sensitive line; the former was superior also in seed yield to the latter. K+ deficiency resulted in lowering the absorption of N and P in the leaves, roots, and seeds of both lines. However, the salt-tolerant line ILL 6796 accumulated significantly greater amounts of N and P in the leaves than the salt-sensitive line ILL 6439. K+ concentrations in the leaves and roots of both lines decreased with decrease in K+ concentrations of the growth medium, whereas Ca2+ concentrations were little affected. ILL 6796 had a greater amount of Ca2+ in the leaves than that in ILL 6439, but a reverse pattern was observed in leaf K+. Mg2+ concentrations in the leaves and roots of both lines declined with decrease in external K+ concentrations, whereas those in the seed increased. There was no effect of K+ deficiency on the absorption of trace elements Fe, Mn, Zn, and Cu in both lines, and the lines had almost similar amounts of these elements. From this study it is clear that in lentil, uptake of major nutrients such as N, P, and Mg was perturbed at K+ deficiency, but in contrast, the absorption of trace elements, Fe, Mn, Zn, and Cu remained unchanged.