Influence of aluminium and nitrate on root growth and mineral nutrition of Norway spruce (Piceaabies) seedlings
Norway spruce (Piceaabies) (L.) Karst.) seedlings were grown in nutrient solutions containing 334, 664, or 1000 μmol•dm−3 nitrate in the presence or absence of 500 μmol•dm−3 aluminium. Over 7 days the rate of root elongation was severely reduced by Al, irrespective of the NO3 concentration. Root elongation was inhibited within 12 h of exposure and this was associated with a displacement of Ca and Mg by Al in the roots. After 35 days, Al significantly reduced Mg and Ca contents of roots and needles. This effect was independent of the NO3 supply. Root growth was stimulated at 1000 μmol•dm−3 NO3 compared with 664 and 334 μmol•dm−3 NO3. This stimulation was inhibited by 500 μmol•dm−3 Al. The results show that spruce seedlings are sensitive to Al, and that NO3 does not modify the toxicity of Al.