The calcium nutrition of bambara groundnut (Vigna subterranea (L.) Verdc.)

Abstract

It is known that the calcium (Ca) requirement of the pods of groundnut (Arachis hypogaea (L.)) will be met by direct uptake of this element by the subterrean pods from the soil. In bambara groundnut (Vigna subterranea (L.) Verdc.), however, some plants have been found to develop some of their pods above-ground. This suggests that the Ca supply of bambara groundnut pods deviates from that in groundnut. Therefore, to elucidate the Ca nutrition of bambara groundnut, with particular emphasis on the supply and internal distribution of Ca within the pod, three experiments were conducted consecutively, in which Ca supply to the roots and pods of bambara groundnut was varied independently using a "double-pot technique". It appeared that calcium supplied to the podding medium was not taken up by the pods. Hence the pods are completely dependent on Ca taken up by the roots. The total Ca accumulated in hull and seed was found to be related to the dry matter mass of each of the two pod compartments. It was found that the amount of Ca accumulated in the pods was low compared with that of leaves. Within the pods, the calcium concentration in hulls was significantly higher than that of the seed. In all cases calcium concentrations in the seed were extremely low, even when external Ca supply was abundant. This suggests that in bambara groundnut, Ca transport from the hull to the seed is the most limiting step in the supply of Ca to the seed.

Ageing, dehulling and cooking of Bambara groundnuts: consequences for mineral retention and in vitro bioaccessibility

“…According to the literature, the accumulation of Ca in the seed coat is attributed to its restricted movement from the seed coat to the cotyledon during seed development due to the formation of insoluble Ca oxalates in the seed coat. 35,36 The same trend was reported in white and mottled common bean varieties, where 70% of total Ca was associated with the seed coat. 37 In contrast, dehulling was not a significant main effect influencing the concentration of Mg, Fe or Zn (Table 3).…”

Changes in Seed Quality during Seed Development and Maturation of Bambara Nut (Vigna subterranea (L.) Verdc.) Landraces

“…One likely efect of the environment could arise from the soil factors of Ca levels and associated acidity of the two sites, with a much higher Ca value for Ocettoke than Koro and lower acidity at Ocettoke than Koro. Tis is due to the fact that Ca is perhaps the most limiting nutrient element in BN seed development [34].…”