Effect of excess aluminum and manganese on Norway spruce seedlings as related to magnesium nutrition

Abstract

Abstract The effects of Al and Mn stress on Norway spruce (Picea abies (L.) Karst.) seedlings were studied in water culture to investigate the role of excess Al and Mn in forest dieback. With low nutrient supply, the plants were affected even at low Al concentrations. Both excess Al and excess Mn induced ‘golden tip chlorosis’ of the needles, which was found to be caused by Mg deficiency. Electron microscopic examination of chlorotic needles revealed starch accumulation and an increase in phenolic inclusions. Excess Al and excess Mn decreased Mg and Ca concentrations in the needles and roots. Increased Mg supply prevented root tip damage under Al stress. The results are discussed with regard to recent forest dieback.