Corn Journal
  • Corn Journal
  • Author
  • Stalk Rot Booklet
  • Seed Testing
  • Corn Genetics
  • Pathology
  • Sponsors
  • Contact
"You can see a lot by just looking"-Yogi Berra

Hormone balance in corn plant

8/16/2018

 
​Cytokinins and auxins are operative during all of the corn plants life, including the movement of sugars to the young kernels.  These two kinds of hormones have different roles in origin and effect on corn growth.  Cytokinins are mostly produced in root tips in root meristems and transported through the water distribution in the xylem tissue.  Auxins are mostly produced in stem meristems and distributed in the phloem system.  Cytokinins are associated with increasing cell division in the stem meristems whereas auxins are involved in cell elongation.  Apical dominance resulting in the corn plant usually having only one upright stem is because of the interactions of the auxins produced in the apical meristem.  Removing that stem tip in early corn development and thus reducing auxin production tips the balance towards more cytokinin and stimulation of cell division in the lateral buds of the corn plant, resulting in branches.
 
Pollination of the multiple ovules in the corn ear results in attraction of cytokinins to each developing kernel.  Moisture stress during the first 10 days after pollination is known to cause early death to some kernels, perhaps because of reduction transportation of cytokinins to the most immature embryos (my conjecture!).  Cell division in the new embryo meristems establishes the movement of sugars through the phloem to the kernels.  Much of the sugar is deposited into the endosperm portion where it is changed to more complex carbohydrates and thus allow the osmotic pressure for more sugar movement towards the kernels.
 
More is known about the effect of these plant hormones on plant growth than all of the mechanisms involved with those effects.  Auxins involvement in cell growth involves softening cell walls, making elongation of cells easier.  Cytokinins have been shown to prevent protein breakdown and activating protein synthesis. 
 
Cytokinins produced in root meristems are transported to and stimulate the cell division in the kernel embryos.  Meristems of those embryos produce auxins.  Auxins are associated with production of ethylene which has been associated with formation of abscission tissue as leaves and fruit mature.  It is assumed that the auxins are associated with formation of the black layer at the base of kernels, resulting in stoppage of movement of material to the kernels.
 
We know that these plant hormones are associated with the growth of corn tissues including the formation of kernels but there remains lots to learn of the actual molecular interactions that allows this to happen.  Meanwhile, corn breeders, agronomists and growers attempt to coordinate it all by selecting the genetics that maximize grain production.

Comments are closed.

    About Corn Journal

    The purpose of this blog is to share perspectives of the biology of corn, its seed and diseases in a mix of technical and not so technical terms with all who are interested in this major crop. With more technical references to any of the topics easily available on the web with a search of key words, the blog will rarely cite references but will attempt to be accurate. Comments are welcome but will be screened before publishing. Comments and questions directed to the author by emails are encouraged.

    Archives

    December 2021
    November 2021
    October 2021
    September 2021
    August 2021
    July 2021
    June 2021
    May 2021
    April 2021
    March 2021
    February 2021
    January 2021
    December 2020
    November 2020
    October 2020
    September 2020
    August 2020
    July 2020
    June 2020
    May 2020
    April 2020
    March 2020
    February 2020
    January 2020
    December 2019
    November 2019
    October 2019
    September 2019
    August 2019
    July 2019
    June 2019
    May 2019
    April 2019
    March 2019
    February 2019
    January 2019
    December 2018
    November 2018
    October 2018
    September 2018
    August 2018
    July 2018
    June 2018
    May 2018
    April 2018
    March 2018
    February 2018
    January 2018
    December 2017
    November 2017
    October 2017
    September 2017
    August 2017
    July 2017
    June 2017
    May 2017
    April 2017
    March 2017
    February 2017
    January 2017
    December 2016
    November 2016
    October 2016
    September 2016
    August 2016
    July 2016
    June 2016
    May 2016
    April 2016
    March 2016
    February 2016
    January 2016
    December 2015

    Categories

    All

    RSS Feed

© COPYRIGHT 2023. ALL RIGHTS RESERVED
  • Corn Journal
  • Author
  • Stalk Rot Booklet
  • Seed Testing
  • Corn Genetics
  • Pathology
  • Sponsors
  • Contact