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

Chances of hypothermia, Name two ways in which the chances of hypothermia c...

Name two ways in which the chances of hypothermia can be reduced during outdoor activities. Eating well before going out and wearing warm, wind-proof clothing can reduces the c

Homeostasis, negative and positive feedback

negative and positive feedback

Male reproductive system - semen, SEMEN - Sperms and secretion of acces...

SEMEN - Sperms and secretion of accesory glands collectively known as seminal fluid or semen. It is milky, semi-solid in nature having particular smell. pH : 7.35 - 7.5. Spe

Explain precautions for isolation of pure culture, Explain Precautions for ...

Explain Precautions for Isolation of Pure Culture? 1. Plating of the medium should be done 24 hours before performing the streaking. There should not be any moisture on the

Evolutionary changes in humans, Evolutionary changes that occurred in human...

Evolutionary changes that occurred in humans are - Development of prominent chin. Increase in cranial capacity. Reduction of brow-ridges. Development of speech. Developme

Is there a exchange of cells between the mother, Is there a exchange of cel...

Is there a exchange of cells between the mother and the fetus through the placenta? Under normal conditions, there is not a passage of cells across the placenta during gestati

Determine the light-near dissociation test, Determine the Light-Near Dissoc...

Determine the Light-Near Dissociation Test The near  response should be  tested  in  a well  lit room  so that  the object  is clearly visible. The patient  is given  an  accom

Animal Cells, what are the functions of cytoplasm ?

what are the functions of cytoplasm ?

Explain the toxicity of folate, Explain the Toxicity of Folate? There ...

Explain the Toxicity of Folate? There is no evidence to suggest that it is possible to consume sufficient natural folate to pose a risk of toxicity. However, this clearly does

Describe about the term - bacterial infections, Describe about the term - B...

Describe about the term - Bacterial Infections Bacterium is a loose generic name for any microorganism (typically one celled) that has no chlorophyll and multiplies by simple d

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