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

INVERTIBREATHE, #question.WRITE THE CHARACTER AND CLASSIFICATION OF MOLLUSC...

#question.WRITE THE CHARACTER AND CLASSIFICATION OF MOLLUSCA ?

What are the main components of the cytoskeleton, The cytoskeleton is a net...

The cytoskeleton is a network of very little tubules and filaments spread throughout the cytoplasm of eukaryotic cells. It is made of microtubules, microfilaments and intermediate

Explain theory for determination of fungal and yeast count, Explain the The...

Explain the Theory or Principle for Determination of Fungal and Yeast Count? Fungi are widespread and present on food, equipments and processing and storage facilities. These a

Synthesis and storage of hormone, Synthesis and Storage of Hormone The...

Synthesis and Storage of Hormone The synthesis and storage of hormone depends on the nature of the hormone. Steroid hormones are secreted in diffuse molecular form and usually

What is oxidation and reduction, What is Oxidation and Reduction? Oxid...

What is Oxidation and Reduction? Oxidation and Reduction :   Most people are familiar with oxidation as it pertains to the rusting of metals. Oxygen grabs electrons from iron

Qualities of a good counsellor, It is important to know about qualities of ...

It is important to know about qualities of a counsellor because you will be counselling a diabetic patient and his family members in clinic/home/hospital and therefore, you shoul

Define the term- life on earth, The article entitled "Life on Earth" is try...

The article entitled "Life on Earth" is trying to make the point that RNA likely included before DNA. Forthis article which of the following is false? A. Chains of RNA nucleoti

Marine extremophiles, how to make a assignment on recent research on marine...

how to make a assignment on recent research on marine microbiology

Plant breeding, #questitypes of plant breeding on..

#questitypes of plant breeding on..

Define briefly about the manganese toxicity, Define Briefly about the Manga...

Define Briefly about the Manganese Toxicity? Manganese is considered least toxic of the trace minerals through oral intake. However, some people may be at a risk to develop tox

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