Re: Hormones

> 
> Joanne Pyszczek wrote:
> >
> >>
> > OK Jim, So when you bud isolate  a plant it causes a release of hormones to
> > encourage the dormant buds to grow?  I may be slow but I'll figure it out
> > eventually.
> > Joanne
> > jopyz@earthlink.net
> > ........................................
> 
> Hi Joanne and others
> 
> I would describe what happens within the rhizome when one "isolates" a
> bud somewhat differently. Bud isolation is a term that Ran uses...it is
> his property, his concept, his discovery. He is letting us use his term
> because we are displaying courtesy by acknowledging his "creatorship".
> This method consists of an incomplete shield-shaped cut around one or
> more dominate buds on the rhizome. The cut does not go down very far
> into the rhizome. I have discussed in private with Ran my opinion of
> what I think happens and I believe he agreed with me. In this case the
> auxin (Indoleacetic Acid) produced by the meristem inside the dominant
> bud around which a cut is made, can not travel to other areas within the
> rhizome. The cut in the rhizome  separates rhizome tissue near the bud
> from the rest of the rhizome. Auxin can not travel by diffusion or by
> any other means because of this physical separation of tissue. Therefore
> there is less auxin in total rhizome tissue which might INHIBIT other
> buds from growing. This allows other less dominant, dormant buds on the
> rhizome to assume a greater degree of apical dominance perhaps when
> environmental factors allow...such as when the temperatures allow growth
> to occur. This cut does not prevent the bud "isolated" from possessing
> its own apical dominance. In the spring it would normally sprout as a
> dominant bud or shoot. Other buds on the rhizome would also sprout with their share of a newly established apical dominance pattern.
> 
> There is also the interacting effect of Abscisic Acid (ABA) with the
> auxin (IAA). At  certain times in the fall, the content of ABA in the
> rhizome may be high enough for ALL buds to be dormant. In this case the
> influence of the different quantities of IAA in different areas of the
> rhizome (such as when we "isolate" a bud) is over-ridden by ABA, the
> natural hormone that controls dormancy.
> 
> I am glad you had only one question. Even that one took a lot of
> explanation. Did I explain how the auxins and ABA hormone works so that
> you understand? Overall understanding is helped by realizing where the
> auxins and ABA hormones are produced and how and when they move in plant
> tissues. The Chart on Hormones helps one understand this.
> 
> Jim

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