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

Evaluate the net energetic gain of the process, Q. How many ATP molecules a...

Q. How many ATP molecules are made after the aerobic respiration and what is the net energetic gain of the process? After aerobic respiration 38 ATP molecules are made with the

A field trip to observe flowers, A field trip to observe flowers:- Plan...

A field trip to observe flowers:- Plan a field trip to view flowers in bloom. If no interesting wildflowers can be found growing near the school, the trip can be planned to a p

What is atomic constipation, Q. What is Atomic constipation? This type ...

Q. What is Atomic constipation? This type is most common; often it is called the "lazy .bowel". There is a loss of muscle tone causing weak peristalsis, the causes are: a) L

Biotic potential curve and the real population growth curve, Q. What is the...

Q. What is the relationship between environmental resistance and the population growth according to the biotic potential curve and the real population growth curve? The differe

Microbiology, control of microorganisms by chemical method.

control of microorganisms by chemical method.

What is the stage of cellular respiration, What is the stage of cellular re...

What is the stage of cellular respiration during which carbon dioxide is liberated? In aerobic cellular respiration the release of carbon dioxide occurs in the transformation o

What is extracellular digestion, Q. What is extracellular digestion? Ex...

Q. What is extracellular digestion? Extracellular digestion is so that in which food breaking into utile molecules that can be internalized by the cell is done in the extracell

What is defective colour vision, What is Defective Colour Vision Defect...

What is Defective Colour Vision Defective colour vision is often called colour blindness. The ability to appreciate one or more of the primary colours is lacking. This can be e

Define plasma or serum ascorbic acid levels, Define Plasma or serum ascorbi...

Define Plasma or serum ascorbic acid levels? The serum or plasma ascorbic acid levels are used as an index of ascorbic acid nutrition of humans. The normal serum values vary ov

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