Geotropism - root and shoot morphogenesis, Biology

Assignment Help:

Geotropism - Root and Shoot Morphogenesis

Roots always grow towards gravity. The lot threshold of geotropic response requires as little time as one minute Gravity pulls auxin to lower side, causing promotion of growth of root tip and elongation. Ethylene induced by auxins also play a role in geotropism. Immediate transient release of ethylene is often part of geotropic response. There are special crystals in plant cells which are heavy enough to perceive gravity. These crystals move towards the direction of gravity and exert a pressure on those of sides of cells, perhaps stimulating a series of changes including auxin production influencing the growth of cells in the direction of gravitation field.

i)  Perception: How does a plant part detect direction of the environmental stimulus that causes the tropism? Where in the plant is located the perception mechanism? It has been difficult to answer these questions for plants, because, in contrast to animals, they do not have specific organs for each function.

ii) Transduction: Whatever be the mechanism of perception. How does it convert or transduce it into a message of stimulus direction to the cells in the organ where tropistic movement occurs? What metabolic or growth regulator changes occur in response to the environmental stimulus? This has been an especially active area of research in biology.

iii) Response: What actually happens during tropistic bending or other responses? Any hypothesis put forth to explain the mechanism of perception and transduction must account for the observed response. Yet the details of each response have been rather neglected for the past few decades-until quite recently. Early researches in the late 1800s and early 1900s made many careful studies of tropistic responses, discovering that cells on one side of the organ grow more than those on the other side, accounting for bending. The result of early workers were either overlooked or completely forgotten, and are beginning to be appreciated for their significance.


Related Discussions:- Geotropism - root and shoot morphogenesis

Describe schizocoelus and its role., Describe Schizocoelus and its role. ...

Describe Schizocoelus and its role. One of two ways that a body cavity forms within mesoderm. (The other is enterocoelic pouching.) Block of mesoderm splits apart to create the

Illustrate about nervous system, Illustrate about Nervous System Functi...

Illustrate about Nervous System Functional unit of nervous system is neuron. Neuron is nerve cell. Information passes through neurons by nerve impulses. Nervous system corre

Explain the mechanism of enzyme action, Question 1 Give an account of t...

Question 1 Give an account of t-RNA 2 Write short note on Competitive inhibition 3 What are ketone bodies? Write the mechanism of ketogenesis 4 Describe the properties of nucle

What are the four groups of protozoans, What are the four groups of protozo...

What are the four groups of protozoans? The four major groups of protozoans are the sarcodines (that form pseudopods, like amoebae), the mastigophores (flagellated, such as the

Respiration – protozoan, Respiration – Protozoan Gas exchange occurs b...

Respiration – Protozoan Gas exchange occurs by the diffusion of oxygen across the cell membrane. Some protozoan utilize this oxygen but are also capable of anaerobic respirati

Define criteria for assessment of pyridoxine status, Define Criteria for As...

Define Criteria for Assessment of Pyridoxine Status? Vitamin B 6 status is most appropriately evaluated by using a combination of indicators,  namely plasma PLP concentration,

What are the components of a balanced diet, Components of a Balanced Diet ...

Components of a Balanced Diet Food which we eat, has effect on the growth and development, and the maintenance of normal body functions. Hence, a good balanced diet is needed t

Direction does growth of one side of branch, To which direction does the gr...

To which direction does the growth of one side of branch, a stem or root induce the structure to curve? Whenever one side of a branch, stem or root grows more than the other si

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

The social environment - stress of hospitalization, The Social Environment ...

The Social Environment   When the child is admitted to the hospital his social environment is totally changed and all health team members are strangers for him. It is your resp

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