Root Proliferation, Proton Efflux, and Acid Phosphatase Activity in Common Bean (Phaseolus vulgaris) Under Phosphorus Shortage

Abstract

The impact of phosphorus (P) availability on root proliferation, proton efflux, and acid phosphatase activities in roots and leaves was investigated in two lines of common bean (Phaseolus vulgaris): BAT 477 and CocoT. Phosphorus was supplied as KH 2 PO 4 at 0 and 60µmol per plant (0P and 60P, respectively). Under P shortage, the plant growth was more restricted in CocoT than in BAT 477, shoots being more affected than roots. The root area increased significantly at 0P in both lines. Up to 1 week following P shortage, the proton efflux increased in both lines despite a higher extent in BAT 477 as compared to CocoT. Root acid phosphatase activity was significantly higher under P limitation in the both lines, this trend being more pronounced in BAT 477 than in CocoT. This was also true for the leaf acid phosphatase. Regardless of the bean line, higher values were recorded for the old leaves as compared to the young ones for this parameter. Interestingly, a significant correlation between Pi content in old leaves and their acid phosphatase activity was found in P-lacking (0P) plants of the both bean lines, suggesting that acid phosphatase may contribute to increase the phosphorus use efficiency in bean through the P remobilization from the old leaves. As a whole, our results highlight the significance of the root H + extrusion and the acid phosphatase activity rather than the root proliferation in the relative tolerance of BAT 477 to severe P deficiency.

Interactive effects of phosphorus deficiency and exogenous auxin on root morphological and physiological traits in white lupin (Lupinus albus L.)

“…In our study, significantly increased proton release ( Figure 5), citrate exudation ( Figure 6), and acid phosphatase activity ( Figure 7) were observed in P-deficient plants compared with P-sufficient ones. These results are in agreement with previous studies in maize (Zea mays L.) [53], common bean [24], white lupin [2729, 54], and purple lupin (L. pilosus Murr.) [5].…”

“…Under P-deficient conditions, some plants, such as white lupin and common bean (Phaseolus vulgaris L.), release large amounts of carboxylates, acid phosphatase, and protons to mobilize and capture P from soils [5,12,24]. In our study, significantly increased proton release ( Figure 5), citrate exudation ( Figure 6), and acid phosphatase activity ( Figure 7) were observed in P-deficient plants compared with P-sufficient ones.…”

“…Increased acid phosphatase activity under P deficiency is well documented in white lupin and other species [24,67]. In a previous study of white lupin, acid phosphatase activity was greater in CRs of P-deficient plants than in nonCRs or in CRs of P-sufficient plants [54].…”

“…The physiological responses influencing P acquisition include proton release [5,23] as well as exudation of carboxylates [5] and phosphatases [24]. Some plants have developed specialized root structures, called cluster roots (CRs), in response to low P availability [25][26][27][28][29].…”

Genotypic Variation for Phosphorus Efficiency of Pigeonpea Genotypes under Varied Phosphorus Levels

“…Fresh root samples were used for the estimation of acid phosphatase enzyme (APase) activity (Kouas et al, 2009). Root tissue 0.1g was homogenized in a chilled glass mortar with a pestle.…”