Plant Growth Hormones

Discussion in 'Plants: Science and Cultivation' started by Shaista, Oct 23, 2003.

  1. Shaista

    Shaista Member

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    Plant Growth Regulators

    I am working with different Plant growth hormones like BA (benzylaminopurine), IBA (3-Indolebutyric acid), NAA (a-naphthalene acetic acid), K (Kinetin) etc. Two hormones are confusing. BA and IBA, giving me different results ….. Mostly BA is used for shooting but in my experiment I am getting significant roots from callus …. And similarly IBA is commonly used for rooting and I am getting shoots … Why is this happening ???? Does it happen normally or related to plant’s own characteristics ?????
     
    Last edited: Feb 3, 2004
  2. T. Shane Freeman

    T. Shane Freeman Active Member

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    Shiasta,

    What species is the callus tissue taken from?
    - Monocot or Dicot?
    - Angiosperm or Gymnosperm?

    Where on the plant is the callus taken from?
    - Root, Shoot, Node, Internode, etc?

    IBA, as you already know, is currently the most common of the various forms of auxin used to promote rooting. It along with NAA are found within the various commercial root-promoting powders. It is put there to specifically promote rooting, just like nature intended. Therefore, I am also stumped why your trials are showing shoot development, instead of roots! Are you sure that you don't have a mislabelled vial/bottle by chance............

    BA, a member of the cytokinins, is highly active and is typically found throughout an entire plant. I remember from my physiology class that one has to be careful when applying any cytokinin, for they are ratio-sensitive. If a high ratio of application is practiced, meristematic cells are produced in the callus, which divide and give rise to others that develop into buds, stems, and leaves, NOT roots. But if the cytokinin ratio of application is lowered, root formation is favored. By choosing the proper rate of application, calli from many species can be made to develop into an entirely new plant. Perhaps, your rate of application is too great............

    Just some thoughts!

    T. Shane Freeman
     
  3. Shaista

    Shaista Member

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    Shane,

    Thank you very much for your thoughts. Actually I was working with anther culture of Datura innoxia. I was trying to develop a protocol for callogenesis and organogenesis from anthers as explants. I used relatively matured anthers for this study. As you know! Anthers at very early stages of development (immature anthers) can produce haploid, diploid and even triploid plants, but my work was a little different. I could develop callus by using 2,4-D, NAA and Kinetin in MS medium. But when I transferred this anther-derived callus to MS medium with BA (0.5–2 mg/l) I observed rooting. I can send you some picture as well. But I am sure it was not mislabeled. I observed rooting from callus at the concentrations of 1 mg/l and 2 mg/l BA in MS medium. And IBA didn’t show rooting at all. Shooting was good when I used IBA, BA, IAA, Kinetin, in different combinations but rooting was only observed with BA and IAA. For a little explanation I must say …. From callus, I could develop roots using BA but no other hormone showed rooting from callus. While shoots transferred to full strength as well as half strength MS medium with these combinations showed no rooting except IAA alone at the concentration of 2 mg/l. But rooting was very rare in my experiment. I couldn’t develop a complete plantlet with plenty of roots. Any other suggestion !!!!!!!!!
     

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