Is there a critical level of shoot phosphorus concentration for cluster-root formation in Lupinus albus?

2008 ◽  
Vol 35 (4) ◽  
pp. 328 ◽  
Author(s):  
Haigang Li ◽  
Jianbo Shen ◽  
Fusuo Zhang ◽  
Caixian Tang ◽  
Hans Lambers
Keyword(s):  
Organic Matter ◽  
Root Formation ◽  
Critical Level ◽  
Lupinus Albus ◽  
White Lupin ◽  
Cluster Roots ◽  
Proton Release ◽  
P Concentration ◽  
Citrate Exudation ◽  
P Supply

This study examined the effects of localised phosphorus (P) supply on cluster-root formation and citrate exudation in white lupin (Lupinus albus L. cv. Kiev Mutant). White lupin plants were grown in nutrient solutions with a range of P supplies in a split-root system with one root half deprived of P and the other root supplied with 0, 2, 5, 8, 10 or 75 μm P. Plants were also grown in soil with or without organic matter added to the top layer. The proportion of cluster roots as a percentage of the total root biomass decreased similarly on both root halves with increasing P supply in the hydroponic experiments. More than 18% of the P taken up by the P-supplied root halves was incorporated into the P-deprived halves. Irrespective of the P supply or organic matter addition in the experiments, the proportion of cluster roots and the rate of citrate exudation decreased sharply with increasing P concentration in the shoots up to a critical level of 2–3 mg P g–1 dry weight. In contrast, the rate of proton release was higher in P-deprived root halves than in P-supplied ones. The formation of cluster roots is regulated by shoot P concentration with a critical level of 2–3 mg g–1. Citrate exudation is predominantly governed by shoot P status, whereas proton release strongly responds to local P supply.

Wheat and white lupin differ in root proliferation and phosphorus use efficiency under heterogeneous soil P supply

2011 ◽  
Vol 62 (6) ◽  
pp. 467 ◽  
Author(s):  
Qifu Ma ◽  
Zed Rengel ◽  
Kadambot H. M. Siddique
Keyword(s):  
Root Zone ◽  
White Lupin ◽  
Cluster Roots ◽  
Phosphorus Use Efficiency ◽  
P Deficiency ◽  
Soil P ◽  
P Use Efficiency ◽  
P Concentration ◽  
Use Efficiency ◽  
P Supply

Heterogeneity of soil nutrients, particularly phosphorus (P), is widespread in modern agriculture due to increased adoption of no-till farming, but P-use efficiency and related physiological processes in plants grown in soils with variable distribution of nutrients are not well documented. In a glasshouse column experiment, wheat (Triticum aestivum L.) and white lupin (Lupinus albus L.) were subjected to 50 mg P/kg at 7–10 cm depth (hotspot P) or 5 mg P/kg in the whole profile (uniform P), with both treatments receiving the same amount of P. Measurements were made of plant growth, gas exchange, P uptake, and root distribution. Plants with hotspot P supply had more biomass and P content than those with uniform P supply. The ratios of hotspot to uniform P supply for shoot parameters, but not for root parameters, were lower in L. albus than wheat, indicating that L. albus was better able than wheat to acquire and utilise P from low-P soil. Cluster roots in L. albus were enhanced by low shoot P concentration but suppressed by high shoot P concentration. Soil P supply decreased root thickness and the root-to-shoot ratio in wheat but had little effect on L. albus. The formation of cluster roots in low-P soil and greater proliferation and surface area of roots in the localised, P-enriched zone in L. albus than in wheat would increase plant P use in heterogeneous soils. L. albus also used proportionally less assimilated carbon than wheat for root growth in response to soil P deficiency. The comparative advantage of each strategy by wheat and L. albus for P-use efficiency under heterogeneous P supply may depend on the levels of P in the enriched v. low-P portions of the root-zone and other soil constraints such as water, nitrogen, or potassium supply.

scholarly journals Nodulated White Lupin Plants Growing in Contaminated Soils Accumulate Unusually High Mercury Concentrations in Their Nodules, Roots and Especially Cluster Roots

Horticulturae ◽  
2021 ◽  
Vol 7 (9) ◽  
pp. 302
Author(s):  
Miguel A. Quiñones ◽  
Susana Fajardo ◽  
Mercedes Fernández-Pascual ◽  
M. Mercedes Lucas ◽  
José J. Pueyo
Keyword(s):  
Contaminated Soils ◽  
Lupinus Albus ◽  
White Lupin ◽  
Cluster Roots ◽  
Cluster Root ◽  
Bioaccumulation Factors ◽  
Aerial Parts ◽  
High Mercury ◽  
Lupinus Albus L ◽  
Hg Accumulation

Two white lupin (Lupinus albus L.) cultivars were tested for their capacity to accumulate mercury when grown in Hg-contaminated soils. Plants inoculated with a Bradyrhizobium canariense Hg-tolerant strain or non-inoculated were grown in two highly Hg-contaminated soils. All plants were nodulated and presented a large number of cluster roots. They accumulated up to 600 μg Hg g−1 DW in nodules, 1400 μg Hg g−1 DW in roots and 2550 μg Hg g−1 DW in cluster roots. Soil, and not cultivar or inoculation, was accountable for statistically significant differences. No Hg translocation to leaves or seeds took place. Inoculated L. albus cv. G1 plants were grown hydroponically under cluster root-promoting conditions in the presence of Hg. They accumulated about 500 μg Hg g−1 DW in nodules and roots and up to 1300 μg Hg g−1 DW in cluster roots. No translocation to the aerial parts occurred. Bioaccumulation factors were also extremely high, especially in soils and particularly in cluster roots. To our knowledge, Hg accumulation in cluster roots has not been reported to date. Our results suggest that inoculated white lupin might represent a powerful phytoremediation tool through rhizosequestration of Hg in contaminated soils. Potential uptake and immobilization mechanisms are discussed.

scholarly journals Nitric oxide is the shared signalling molecule in phosphorus- and iron-deficiency-induced formation of cluster roots in white lupin (Lupinus albus)

2012 ◽  
Vol 109 (6) ◽  
pp. 1055-1064 ◽  
Author(s):  
Zhi Bin Meng ◽  
Li Qian Chen ◽  
Dong Suo ◽  
Gui Xin Li ◽  
Cai Xian Tang ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Iron Deficiency ◽  
Lupinus Albus ◽  
White Lupin ◽  
Cluster Roots ◽  
Signalling Molecule

Root-derived auxin contributes to the phosphorus-deficiency-induced cluster-root formation in white lupin (Lupinus albus)

2012 ◽  
Vol 148 (4) ◽  
pp. 481-489 ◽  
Author(s):  
Zhi Bin Meng ◽  
Xue Di You ◽  
Dong Suo ◽  
Yun Long Chen ◽  
Caixian Tang ◽  
...  
Keyword(s):  
Root Formation ◽  
Phosphorus Deficiency ◽  
Lupinus Albus ◽  
White Lupin ◽  
Cluster Root

scholarly journals Leaf Phosphorus Concentration Regulates the Development of Cluster Roots and Exudation of Carboxylates in Macadamia integrifolia

2021 ◽  
Vol 11 ◽  
Author(s):  
Xin Zhao ◽  
Yang Lyu ◽  
Kemo Jin ◽  
Hans Lambers ◽  
Jianbo Shen
Keyword(s):  
Critical Value ◽  
Cluster Roots ◽  
Phosphorus Concentration ◽  
Acid Phosphatases ◽  
P Deficiency ◽  
Cluster Root ◽  
Macadamia Integrifolia ◽  
P Concentration ◽  
Leaf P ◽  
P Supply

Phosphorus (P) deficiency induces cluster-root formation and carboxylate exudation in most Proteaceae. However, how external P supply regulates these root traits in Macadamia integrifolia remains unclear. Macadamia plants were grown hydroponically with seven P levels to characterize biomass allocation, cluster-root development, and exudation of carboxylates and acid phosphatases. Plant biomass increased with increasing P supply, peaking at 5 μM P, was the same at 5–25 μM P, and declined at 50–100 μM P. Leaf P concentration increased with increasing P supply, but shoot biomass was positively correlated with leaf P concentration up to 0.7–0.8 mg P g–1 dry weight (DW), and declined with further increasing leaf P concentration. The number of cluster roots declined with increasing P supply, with a critical value of leaf P concentration at 0.7–0.8 mg P g–1 DW. We found a similar trend for carboxylate release, with a critical value of leaf P concentration at 0.5 mg g–1 DW, but the activity of acid phosphatases showed a gradually-decreasing trend with increasing P supply. Our results suggest that leaf P concentration regulates the development and functioning of cluster roots, with a critical P concentration of 0.5–0.8 mg g–1, above which macadamia growth is inhibited.

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