Phosphorus efficiency of plants

Abstract

F6hse et al. (1988) have shown that P influx per unit root length in seven plant species growing in a low-P soil varied from 0.6 × 10 -14 to 4.8 × 10 -14 mol cm-ls -1. The objective of this work was to investigate the reasons for these differences. No correlation was found between P influx and root radius, root hairs, cation-anion balance and Ca uptake. However, when root hairs were included in mathematical model calculations, the differences of P influx could be accounted for. These calculations have shown that in soils low in available P, contribution to P uptake by root hairs was up to 90% of total uptake.The large contribution of root hairs to P uptake was partly due to their surface area, which was similar to that of the root cylinder. However, the main reason for the high P uptake efficiency of root hairs was their small radius (approx. 5 × 10 -4 c m ) and their perpendicular growth into the soil from the root axis. Because of the small radius compared to root axes, P concentration at root hair surfaces decreased at a slower pace and therefore P influx remained higher. Under these conditions higher Ima x (maximum influx) or smaller K m values (Michaelis constant) increased P influx. The main reasons for differences found in P influx among species were the size of Ima x and the number and length of root hairs. In a soil low in available P, plant species having more root hairs were able to satisfy a higher proportion of their P demand required for maximum growth.

Root Hair Development in the Grasses: What We Already Know and What We Still Need to Know

“…In barley (Brown et al, 2012) and maize (Zhu et al, 2010), low P availability induces an increase in RH length, which is assumed to boost the efficiency of P uptake (Haling et al, 2013). Under P-limiting conditions, up to 90% of the mineral appears to be taken up by the RHs in different plant species (Fohse et al, 1991), a proportion that readily explains the major difference in the P acquisition capacity between barley accessions that form short as opposed to long RHs (Gahoonia and Nielsen, 2004;Brown et al, 2012). The importance of RHs for both cadmium and zinc acquisition has been illustrated by comparing the performance of the barley root-hairless mutant bald root barley (brb) with that of its parent cv Pallas.…”

Screening Chinese Wheat Germplasm for Phosphorus Efficiency in Calcareous Soils

“…Some researchers have also found that P or other nutrient efficiency can be achieved by uptake or utilization efficiency (Clark, 1983;Gabelman and Gerloff, 1983;Föhse et al, 1988;Sattelmacher et al, 1994). Other researchers have observed that at high P supply, P efficiency was more favored by a high P uptake, Table 6 Phosphorus uptake and utilization efficiency of wheat genotypes at the shooting stage in the pot experiment P concentration P uptake P-utilization efficiency mg g whereas in P-deficiency conditions it was likely explained by a high internal P-utilization efficiency (Stelling et al, 1996).…”

Absorção de fósforo em doze genótipos de milho inoculados com fungo micorrízico arbuscular em solo de cerrado

“…Tais diferenças têm sido relacionadas, basicamente, à eficiência com que as plantas absorvem o nutriente da solução e/ou utilizam-no internamente (FURLANI et al, 1985;FÖHSE et al, 1988;JONES et al, 1992). Vários fatores distinguem a capacidade de absorção de fósforo entre genótipos.…”