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

What do you mean by pelvic girdle, What do you mean by Pelvic Girdle? B...

What do you mean by Pelvic Girdle? Bones in vertebrates which connect the appendages on left and right side of the posterior appendicular skeleton to each other. Pelvic girdles

Somatic and germline gene therapy, All the cells present in the body contai...

All the cells present in the body contain genes and an approach targeted to modulate the expression of genes is known as gene therapy. This novel approach has emerged by the end of

Explain the metabolic alterations during cancer, Explain the Metabolic Alte...

Explain the Metabolic Alterations during Cancer? As we have studied earlier, patients with advanced cancer experience profound anorexia, early satiety, changes in the structure

How can you identify the signs and symptoms, Identify the signs and symptom...

Identify the signs and symptoms associated with death from mercury. Explain Please.

Medicines and drugs - impacts on biodiversity, Q. Medicines and Drugs - imp...

Q. Medicines and Drugs - impacts on biodiversity? The World Health Organization (WHO) has listed over 21,000 plant names (including synonyms) that have recorded medical uses ar

Explain anaplerotic reactions, Anaplerotic Reactions Anaplerotic  reac...

Anaplerotic Reactions Anaplerotic  reactions are  reactions  that  replenish the  intermediates of  citric acid cycle. The  special  enzymatic mechanisms  by  which  the  pool

Endocrine glands, Endocrine glands Endocrine glands have no ducts - ...

Endocrine glands Endocrine glands have no ducts - so these are also called as ductless glands Eg.Pituitary etc., These glands secrete chemical substances called HORMONES

Explain both food and light as zeitgebers, Must account for both food AND l...

Must account for both food AND light as zeitgebers Because of the continuous light / dark periods of the year; light not always able to act as a zeitgeber. Food

How much dna is in each stage, In meiosis - starting from stage G1 through ...

In meiosis - starting from stage G1 through the completion of meiosis, how much DNA is in each stage/phase when referring to the nucleus of spermatagonia?

Collecting tubule - vertebrate kidney, Normal 0 false false ...

Normal 0 false false false EN-IN X-NONE X-NONE MicrosoftInternetExplorer4

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