Plant and Soil

, Volume 157, Issue 1, pp 121–129 | Cite as

The 2,4-D-induced wheat para-nodules are modified lateral roots with structure enhanced by rhizobial inoculation

  • Perigio B. FranciscoJr.
  • Shoichiro Akao
Research Article


Nodular outgrowths (para-nodules orp-nodules) on the roots of wheat (Triticum aestivum L.) cv. Miskle seedlings were induced by treatment with 0.3 and 0.6 mg L-1, 2,4-dichlorophenoxyacetate (2,4-D). When co-inoculated withRhizobium trifolii strain ATCC 14480, morep-nodules were formed at these levels andp-nodulation occured at 0.1 mg L-1 indicating that inoculation enhances 2,4-D-inducedp-nodulation. Similar to lateral roots, thep-nodules arose from the pericycle opposite the phloem tissues and were free from the cortical cells of the parental root at all stages of development. Structurally, thep-nodules exhibited tissue differentiation. They possessed a highly organized central vascular cylinder connected to that of the parent root, an endodermis, a cap, and an apical and lateral meristems.P-nodules formed by 2,4-D treatment alone were irregularly lobed due to uncoordinated activity of the apical meristem, while those in the combined 2,4-D and inoculation treatment were more globose. The results of the present study indicate that the 2,4-D-induced wheatp-nodules are modified lateral roots, the structure of which is enhanced by rhizobial inoculation.

Key words

2,4-dichlorophenoxyacetate para-nodule Rhizobium trifolii structure Triticum aestivum L. wheat 


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Copyright information

© Kluwer Academic Publishers 1993

Authors and Affiliations

  • Perigio B. FranciscoJr.
    • 1
  • Shoichiro Akao
    • 2
  1. 1.Institute of Biology, College of ScienceUniversity of the PhilippinesQuezon CityPhilippines
  2. 2.Laboratory of Nitrogen FixationNational Institute of Agrobiological ResourcesTsukuba City, IbarakiJapan

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