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

Seedling Changes

5/11/2021

 

The initial roots growing from the embryo radical supply the emerging seedling with water and nutrients. Other changes then occur.
 
After the first corn leaves emerge, the hormonal message to the mesocotyl tissue is to stop pushing upwards. Apical meristem, at the tip of the mesocotyl is now below the soil surface where the first leaf is attached. Photosynthesis now drives the metabolism of the young seedling as it switches from dependence upon the seed endosperm for carbohydrates.  Cell division in the meristem produces new leaves, each attached to the young stem under the soil surface and attached in distinct clusters of newly dividing cells called nodes.  These nodes are then stimulated to produce roots at about the time the 4th leaf appears in the young seedling.  Because the roots are being produced from stem tissue, they are called adventitious roots.  As the primary root, that had grown initial seed, loses its energy source, adventitious roots become the main roots for the plant.
 
The first 4-5 nodes of the young stem remain underground, each producing the roots for the plant, even as the first leaves remain attached at the same locations.  What appears to be stem in a 4-5 leaf seedling is a compilation of leaf sheaths tightly wrapped together while the actual stem remains beneath the surface. The underground stem portion, formerly attached to the mesocotyl, with adventitious roots becomes known as the crown.  Eventually the mesocotyl deteriorates as it is deprived on nutrition and loses resistance to the many soil organisms.
 
As the stem growing point eventually emerges above the soil surface a few exposed nodes will often form the brace roots to further support the adult plant. A lot of changes in a relatively short time after seed is planted.


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