Dynamic Development of White Lupin Rootlets Along a Cluster Root

White lupin produces cluster roots in response to phosphorus deficiency. Along the cluster root, numerous short rootlets successively appear, creating a spatial and temporal gradient of developmental stages that constitutes a powerful biological model to study the dynamics of the structural and functional evolution of these organs. The present study proposes a fine histochemical, transcriptomic and functional analysis of the rootlet development from its emergence to its final length. Between these two stages, the tissue structures of the rootlets were observed, the course of transcript expressions for the genes differentially expressed was monitored and some physiological events linked to Pi nutrition were followed. A switch between (i) a growing phase, in which a normal apical meristem is present and (ii) a specialized phase for nutrition, in which the rootlet is completely differentiated, was highlighted. In the final stage of its determinate growth, the rootlet is an organ with a very active metabolism, especially for the solubilization and absorption of several nutrients. This work discusses how the transition between a growing to a determinate state in response to nutritional stresses is found in other species and underlines the fundamental dilemma of roots between soil exploration and soil exploitation.

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Update on White Lupin Cluster Root Acclimation to Phosphorus Deficiency Update on Lupin Cluster Roots

PLANT PHYSIOLOGY ◽

10.1104/pp.111.175174 ◽

2011 ◽

Vol 156 (3) ◽

pp. 1025-1032 ◽

Cited By ~ 46

Author(s):

Lingyun Cheng ◽

Bruna Bucciarelli ◽

Jianbo Shen ◽

Deborah Allan ◽

Carroll P. Vance

Keyword(s):

Phosphorus Deficiency ◽

White Lupin ◽

Cluster Roots ◽

Cluster Root

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

Horticulturae ◽

10.3390/horticulturae7090302 ◽

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.

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Expression of plasma membrane H+ -ATPase in cluster roots of white lupin under phosphorus deficiency

Journal of Plant Nutrition and Soil Science ◽

10.1002/jpln.201900124 ◽

2019 ◽

Vol 182 (6) ◽

pp. 867-870

Author(s):

Sophie Stein ◽

Franziska Faust ◽

Stephan Jung ◽

Sven Schubert

Keyword(s):

Plasma Membrane ◽

Phosphorus Deficiency ◽

White Lupin ◽

Cluster Roots

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Cluster root formation by Gymnostoma papuanum (Casuarinaceae) in relation to aeration and mineral nutrient availability in water culture

Canadian Journal of Botany ◽

10.1139/b90-323 ◽

1990 ◽

Vol 68 (12) ◽

pp. 2564-2570 ◽

Cited By ~ 30

Author(s):

Suzanne Racette ◽

Isabelle Louis ◽

John G. Torrey

Keyword(s):

Root Growth ◽

Root Formation ◽

Phosphorus Deficiency ◽

Lateral Roots ◽

Critical Factor ◽

Mineral Nutrient ◽

Cluster Roots ◽

Phosphorus Level ◽

Water Culture ◽

Cluster Root

The term cluster root is used to refer to a dense cluster of determinate lateral roots (rootlets), in preference to the terms proteoid root and proteoid-like root used by other authors. Cluster roots are often formed by the actinorhizal plant Gymnostoma papuanum. In water culture, cluster root formation by G. papuanum was influenced by aeration, phosphorus level, and nitrogen source. Aeration was a critical factor, with nonaerated rooted cuttings having far fewer cluster roots than aerated ones. Phosphorus deficiency was the single nutrient deficiency that led to increased cluster root formation. Seedlings, grown under conditions of either low (0.8 mg∙L−1) or no phosphorus, responded by devoting a greater portion of root growth to the production of cluster roots, with no overall reduction in root growth for 6 weeks. The response to varying phosphorus level was modified by providing nitrogen in different forms. Supplying nitrogen as ammonium resulted in low levels of cluster root formation. Supplying nitrate to nodulated seedlings led to an increase in cluster root formation in comparison with plants that depended solely upon dinitrogen fixation by Frankia. Greatest cluster root formation occurred on plants grown in aerated water cultures supplied with nitrate and with little or no phosphorus. Key words: Gymnostoma papuanum, cluster roots, proteoid roots, phosphorus deficiency.

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