Effects of cation leaching on mineral cycling and transpiration: investigations with beech seedlings, <i>Fagus sylvatica</i> L.

Abstract

Beech seedlings (Fagus sylvatica L.) were sprayed with acidic or ammonium-rich solutions of different concentrations, 10^-3 or 10^-5 mol l^-1 H⁺ or NH₄ ⁺ . Whilst the leaching of Ca and Mg was increased by the more acid treatment, the K leaching was decreased. On the other hand, the concentrated NH₄ ⁺ mist led to a substantial increase in the leaching of K. As a consequence of the greater uptake of cations due to their leaching, more protons were released to the nutrient solution and into the rhizosphere of potted plants. Increased transpiration was observed following the application of acidic mist to the plants in nutrient solution but decreased stomatal diffusive resistance of potted plants was detected only at night. Acid mist caused changes in stomatal behaviour that were responsible for a rapid and greater water loss of detached leaves.