The effect of Ca and Al concentration on alleviation of Al toxicity on non-symbiotic growth of groundnut

R. Kasran, Z. H. Shamsuddin and N. J. Grundon

Abstract

A 21-day solution culture study was conducted to determine the external calcium (Ca) concentration required to alleviate aluminium (Al) toxicity on non-symbiotic growth of groundnut (Arachis hypogaea L.) cv. Matjam at pH 4.3. The Ca concentrations were maintained at 500, 1 000, 2 500, 5 000 and 10 000 μM, while the sum activities of monomeric Al species (Σa_Almono) were 0, 15, 30 and 60 μM. The relative yield of plant tops was decreased with Σa_Almono of 15 μM in solution except at 2 500 μM Ca. Relative yields declined further with Σa_Almono of 30 μM, and even further with 60 μM Σa_Almono. The effect was more marked at low Ca concentration. A 2 500 μM external Ca concentration was required to alleviate Al toxicity at 24 μM Σa_Almono. The Ca concentration in the youngest expanded leaf (YEL) decreased with Al treatment but increased with increased Ca concentration in solution. However, magnesium (Mg) concentration in YEL
was decreased with increased Ca and Al.

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