%0 Article
%T Effect of foliar application with acid mist on the photosynthesis of potassium-deficient Scots pine seedlings.
%A Nygren, Pekka
%A Hari, Pertti
%D 1992
%J Silva Fennica
%V 26
%N 3
%R doi:10.14214/sf.a15642
%U https://silvafennica.fi/article/5481
%X <p>The interactive effects of potassium deficit and foliar application with acid water (pH 5.5, 4.5, 4.0 and 3.0 given consecutively) on CO<sub>2</sub> exchange rate of <em>Pinus sylvestris</em> L. seedlings was investigated in field conditions. No reduction of the CO<sub>2</sub> exchange rate was observed in the seedlings supplied with sufficient potassium. Only the seedlings having the lowest needle K concentration (2.4 mgg<sup>-1</sup>) had an apparently low CO<sub>2</sub> exchange rate before the applications with acid water. The CO<sub>2</sub> exchange rate of most of the seedlings with low needle K concentration (3.9–6.0 mgg<sup>-1</sup>) decreased after the acid water application. The threshold acidity for the reduction varied between pH 4,0 and 3.0 depending on the needle K concentration. The reduction was more apparent at high irradiance. It was concluded that acid precipitation disturbs the CO<sub>2</sub> exchange only in conditions of mineral nutrient deficit.</p>
<p>The PDF includes an abstract in Finnish.</p>