The effect of Ca and Al concentration on alleviation of Al toxicity on non-symbiotic growth of groundnut (Kesan kepekatan Ca dan Al untuk mengurangkan keracunan Al terhadap pertumbuhan bukan simbiotik kacang tanah)

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 ( ∑ a Almono ) were 0, 15, 30 and 60 µM. The relative yield of plant tops was decreased with ∑ a Almono of 15 µM in solution except at 2 500 µM Ca. Relative yields declined further with ∑ a Almono of 30 µM, and even further with 60 µM ∑ a 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 ∑ a 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.