Cytokinins - apical dominance, Biology

Assignment Help:

Cytokinins - Apical Dominance

Cytokinins are also involved in the regulation of apical dominance. Wickson and Thimann studied the interaction of cytokinins and auxins in controlling the apical dominance. They isolated and cultured pea the stem sections in nutrient media containing auxins and no auxins. In the absence of auxins growth of lateral buds was not prevented. However, if cytokinins were added along with auxins, the inhibition of lateral buds was released. Wickson and Thimann also demonstrated the effect of cytokinins on entire shoots. When the intact shoot was soaked in a solution of kinetin, growth of lateral buds occurred even in the presence of shoot apical buds.

From this observation it was inferred that apical dominance exhibited by the shoot apex was overcome by the application of cytokinins. The present concept is that apical dominance is controlled by a balance between cytokinin and auxin concentrations. Some investigators suggest the possible inhibitory influence of cytokinins on auxin production. The cytokinin application to the lateral buds may inhibit the synthesis of certain forms of IAA oxidase, normally induced by IAA translocated from the terminal bud. With the repression of IAA oxidase, the spared auxin may stimulate lateral bud growth and shoot development. In addition to the possible inhibition of IAA degradation, cytokinins may initiate a sink effect at the site of lateral buds to attract diversion of nutrients from other regions.


Related Discussions:- Cytokinins - apical dominance

Chronic respiratory disease (crd), C h r on i c respiratory disease (C...

C h r on i c respiratory disease (CRD) Infection with Mycoplasma gallisepticum is characterized by slow onset; CRD is seen in chickens, turkeys, and other birds. Ducks f

Transcription of eukaryotic protein coding genes, 1. The transcription and ...

1. The transcription and replication of DNA requires a multitude of protein complexes a. Describe the events that occur during the initiation of transcription of eukaryotic prot

Pisces, what is the mode of nutrition in pisces

what is the mode of nutrition in pisces

Examples of natural selection, EXAMPLES OF NATURAL SELECTION - 1 .   ...

EXAMPLES OF NATURAL SELECTION - 1 .       INDUSTRIAL MELANISM - First studied by Fischer & Ford (1845) on pepperd moth (Biston betularia) of two types : grey moth (B.

Membrane oxygenators-type of oxygenators , Membrane Oxygenators: They are...

Membrane Oxygenators: They are more physiological and are similar to natural lungs. There is separation of blood and gas by membrane across which gas exchange takes place. There

What are interferons, Interferons are small glycoproteins formed by virus-i...

Interferons are small glycoproteins formed by virus-infected cells that inhibit viral infection. They are heterogeneous. Gamma interferons induce MHC class II antigens in macrophag

What is the tertiary structure of a protein, The tertiary protein structure...

The tertiary protein structure is a spatial conformation additional to the secondary structure in which the alpha helix or the beta-sheet folds up itself. The forces that stay the

Oogenesis, New advancements and discoveries related to oogenesis

New advancements and discoveries related to oogenesis

Function of adenosine in brain, Q. Function of Adenosine in brain? Aden...

Q. Function of Adenosine in brain? Adenosine has four different receptor subtypes (A1, A2A, A2B and A3). Adenosine A2A receptors are concentrated in striatum. Adenosine recepto

Define the criteria for an indicator organism, Define the Criteria for an I...

Define the Criteria for an Indicator Organism? Following criteria are suggested for an indicator organism: i. It should be suitable for the analysis of all types of water, i

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd