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

Explain failing implant and biologic failure, Explain Failing implant and b...

Explain Failing implant and biologic failure Failing implant : An implant that is progressively losing bone but is clinically stable (firm) can be defined as failing. Bio

Essay, “Define nosocomial infections. Discuss the factors that might influe...

“Define nosocomial infections. Discuss the factors that might influence whether a patient may acquire nosocomial infection. How might these risks be reduced?”

Explain about dry heat sterilization, Q. Explain about Dry heat sterilizati...

Q. Explain about Dry heat sterilization? It is used to sterilize glass ware, forceps, scissors, scalpels, all glass syringes, swabs, some pharmaceuticals products such as liqui

Paper points & chemicals removal of gutta percha, Paper points & chemicals ...

Paper points & chemicals removal of gutta percha: -  Flushing action: residual of qutta- percha and sealers chemically solvent by floating pulp chamber with chloroform. -  Chem

How to use a key, Q. How to Use a Key? The use of a key is analogous to...

Q. How to Use a Key? The use of a key is analogous to travelling a high way, that forks repeatedly, each fork having roadside directions. If a traveller follows the proper dire

Water-soluble vitamins for school children and adolescents, Determine Water...

Determine Water-soluble vitamins needs of school children and adolescents? The suggested requirements are given in Table 15.2 (ICMR 1990). Thiamine is computed as 0.5 mg/1000 K

Preprocedure care, BRONCHOSCOPY: Bronchoscopy is the passage of lighte...

BRONCHOSCOPY: Bronchoscopy is the passage of lighted bronchoscope into the bronchial tree. Bronchoscopy may be performed with  rigid steel of flexible fiberoptic instruments.

Define promoting food security to control under nutrition, Define Promoting...

Define Promoting food security to control under nutrition? Public distribution of food grains through a network of ration shops, particularly to reach the population below the

Explain the organisation of the intensive care unit, Explain the organisati...

Explain the organisation of the intensive care unit? The following kinds of professional groups are required in the day to day functioning of a modern intensive care unit: Th

Define limitations of agar syringe or agar sausage method, Define Limitatio...

Define Limitations of Agar Syringe or Agar Sausage Method? (i) It is applicable to surfaces with low contaminants. (ii) Problem of spreading colonies may occur. (iii) Col

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