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

Explain about blood pressure, Explain about Blood pressure Blood press...

Explain about Blood pressure Blood pressure is explained as the force exerted by the blood against the walls of the arteries. Blood pressure (BP) can be described as the fo

Epiboly of ectoderm, Epiboly of Ectoderm Like the presumptive endoder...

Epiboly of Ectoderm Like the presumptive endodermal notochordal and mesodermal cells migrate inward the areas in the epiblast vacated through them are occupied by expansion (

Chapter-2, multiple choise question

multiple choise question

Lead to protein denaturation, Q. What are some factors that can lead to pro...

Q. What are some factors that can lead to protein denaturation? Protein denaturation can be caused by temperature variation, pH change, changes in the concentration of surround

Define preoperative nutritional care during surgery, Define Preoperative Nu...

Define Preoperative Nutritional Care during Surgery? It can be provided only to prospective candidates of elective surgery and is not feasible for emergency cases. Preoperative

Simple lipids, SIMPLE  LIPIDS They are lipids formed of fatty acids an...

SIMPLE  LIPIDS They are lipids formed of fatty acids and alcohol without any additional group. e.g. fats or true fats,wax,cutin, suberin. Simple lipids are mainly of 2 types

Explain counter stain - ziehl-neelsen method, Explain Counter Stain - Ziehl...

Explain Counter Stain - Ziehl-Neelsen Method? Methylene blue is used to stain previously decolourized cells. All non acid-fast bacteria de-stained by acid alcohol now absorbs c

Homework, 1) a) Initially, how do skeletal muscles (the type of muscle atta...

1) a) Initially, how do skeletal muscles (the type of muscle attached to bones) make ATP? b) write the reaction for this procss (Crp +ADP => Cr + ATP) as a ''coupled'' reaction, id

Explain cori cycle , Under the limiting oxygen conditions experienced in ...

Under the limiting oxygen conditions experienced in by vigorous exercise, the configuration of NADH by glycolysis exceeds the ability of the respiratory chain to oxidize it back to

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