Accumulation and distribution of mineral elements in the annual lupins Lupinus albus L. and Lupinus angustifolius L

Abstract

The mineral nutrition of L. albus and L. angustifolius was studied under nutrient-sufficient conditions in sand culture.

Mineral accumulation by both species was closely synchronized with dry matter accumulation. Fruits acquired major proportions of the nitrogen, phosphorus, potassium, magnesium and zinc of both species. Leaflets were major sites of accumulation of calcium, iron and manganese; stem and petioles accumulated substantial amounts of potassium, phosphorus, magnesium, copper and sodium. Intensities of intake of calcium, magnesium and iron by roots of L. angustifolius were higher than in L. albus. The situation was reversed for sodium.

Cotyledon reserves of nitrogen, phosphorus, potassium and zinc were mobilized to seedling parts with 85–97% efficiency, other elements much less effectively. During fruiting, vegetative parts of the shoot showed net losses of 60–80% of their nitrogen, phosphorus and potassium, 20–50% of their magnesium, iron, zinc, manganese and copper, and less than 15% of their calcium and sodium. Mobilization from vegetative structures was generally more efficient in L. albus than in L. angustifolius. Leaflets showed higher mobilization efficiencies than stem and petioles.

Post-anthesis mobilization furnished the equivalent of 23–59% of the fruit's intake of nitrogen, phosphorus, potassium, magnesium and manganese, 10–25% of the zinc, calcium, iron and copper, and 2% or less of the sodium. Nitrogen, phosphorus and potassium attained higher concentrations in fruits than in mature, non-reproductive parts; less mobile elements (calcium, sodium, iron and manganese) showed the opposite effect. Concentrations of sodium and manganese were especially low in fruits of L. angustifolius compared with L. albus.