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

Effects of noise - noise pollution, Effects of Noise - Noise Pollution ...

Effects of Noise - Noise Pollution Noise can affect in the following three ways: Interferes with communication, Diminishes hearing and Affects health and even

Lateral roots - root apex, Lateral Roots - Root Apex Lateral roots no...

Lateral Roots - Root Apex Lateral roots normally arise at a definite distance behind the tip from areas close to or opposite the points of xylem star. So, a triarch root can

Why dietary supplements do not speed up a child''s growth, Why Dietary supp...

Why Dietary supplements do not speed up a child's growth? Dietary supplements do not "speed up" a child's growth and development: There is no scientific evidence that me

How dietary iron is absorbed in my blood vessels, What pathway does dietary...

What pathway does dietary iron follow in blood vessels

Similarities between cardiac, SIMILARITIE S BETWEEN CARDIAC AND SKELETAL M...

SIMILARITIE S BETWEEN CARDIAC AND SKELETAL MUSCLES - Both cardiac and skeletal muscles are made up of elongated fibres which have numerous myofibrils. The myofibrils of

Rabbit femur, describe the features of the rabbit femur bone

describe the features of the rabbit femur bone

Explain antimicrobial prophylaxis, Explain Antimicrobial Prophylaxis An...

Explain Antimicrobial Prophylaxis Antimicrobial prophylaxis can decrease the incidence of infection, particularly surgical site infection, after certain operations, but this be

What is telophase, What is telophase? Telophase is the cell divides apa...

What is telophase? Telophase is the cell divides apart and screws itself.

Determine nutritional requirements for high altitude, Determine Nutritional...

Determine Nutritional Requirements for High Altitude? High terrestrial altitudes and mountains have aroused great fascination and cham for mankind. Every year millions of peopl

Determine the end of the meiotic process during oogenesis, What is the rela...

What is the relation among fecundation and the end of the meiotic process during oogenesis? The oocyte II only completes the second meiotic division (interrupted at metaphase) i

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