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

What are the antigen-respective antibodies abo blood group, What are the an...

What are the antigens and the respective antibodies of the ABO blood group system? The ABO blood system contain the erythrocytic antigens A and B that can be attacked by the an

What er the parafunctional habits, What er the Parafunctional Habits P...

What er the Parafunctional Habits Parafunctional Habits like bruxism and clenching create mechanical and biological problems due to overloading and are considered to be one of

Why are euglenas involved in polemics, Q. Why are euglenas involved in pole...

Q. Why are euglenas involved in polemics related to their taxonomic classification? Euglenas are involved in taxonomic polemics because they tend to be classified sometimes as

What are the effects of protease inhibitors, What are the effects of protea...

What are the effects of protease inhibitors?  In experimental animals, they have been found to be associated with growth inhibition and pancreatic hypertrophy. A negative feedb

What is the karyotype found in down syndrome, What is the karyotype found i...

What is the karyotype found in Down syndrome? Down syndrome is an aneuploidy, i.e., a numeric changing of chromosomes within the cells compared to the normal number of chromoso

Antimicrobial prophylaxis - number of doses, Timing and number of doses ...

Timing and number of doses It has been common practice to give antibiotics at the time of anesthesia induction, which results in adequate serum and tissue levels of the drugs;

Explain homozygosity and heterozygosity, What is the difference between hom...

What is the difference between homozygosity and heterozygosity? Homozygosity happens when an individual has two identical alleles of a gene, for instance, AA or aa. Heterozygos

Class polychaeta - classification of coelom, Class Polychaeta - Classificat...

Class Polychaeta - Classification of Coelom There are mainly marine forms with distinct head, having eyes and tentacles, segments have lateral projections of the body wall ter

One benefit of including vegetable fibre in the diet, State one benefit of ...

State one benefit of including vegetable fibre (roughage) in the diet   Vegetable fibre retains water (keeping the faeces soft and bulky), stops constipation, decreases the

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