Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Phototropism - Root and Shoot Morphogenesis
Paratonic growth movement of part of a plant in response to light, e.g. bending of stems of indoor plants towards a window, brought about by increased elongation of cells in growth region at tip of stem on shaded side. Coleoptiles of dark grown Avena seedlings bend towards light, when we provide unilateral light. The tip is found to be playing a role. Actually the tip is site of auxin production. If the tip is removed there is no response to unilateral light. But an agar block containing auxins can substitute for the tip and coleoptile would bend towards the light as if it had not been decapitated. The coleoptile bends towards light because of unequal elongation of cells on two sides. The cells on the darker side elongate faster than those cells on two sides exposed to light.
Generally accepted that effect is due to greater concentration of auxin on dark side than on side facing light but some recent evidence suggests asymmetric distribution of some co-factor that influences auxin effect. Shoots always bend and grow towards light. It is an adaptive mechanism, no doubt. Here, also the auxin is agents that mediate light control just as in coleoptile. One question that needs to be asked is whether the extent of phototropism is proportional to the duration of exposure to light. Secondly, whether the magnitude of curvature is proportional to the energy content of the inducing light.
Which are the plant tissues responsible for the supporting of the plant? The plant supporting tissues are the collenchyma and the sclerenchyma. The collenchyma is made of li
What is the function of the umbilical cord? The umbilical cord is a set of blood vessels that connects the fetus with the placenta. In the fetus one extremity of the cord inse
What is Class Reptilia ? Class Reptilia include the vertebrates that have successfully transitioned to a terrestrial lifestyle by evolving protective scales and a "land egg."
Dormancy - Plant Growth Substances Dormancy can be defined as a state of suspended growth and metabolism. When most plants are exposed to seasonal periods of very inclement we
Deficiency of vitamin -A (hypovitaminosis-A) Vitamin A deficiency develops due to insufficient supply of the vitamin or its defective absorption from alimentary tract. The defi
Explain the Metabolism - Zinc? Zinc has been found to play an important biological role in our body. Zinc ions can be chelated and precipitated by a number of chelating agents
How does the study of fossils strengthen the theory of evolution? The study of fossils reveals ancient and extinct species having many same structures to others of the present
Explain the Adsorption or Binding Ability? Some fibre components have the ability to bind (adsorb) substances in the gastrointestinal tract. Wheat bran, guar gum, mannan and is
Explain the Crestal Bone Levels Crestal Bone Levels: Bone levels should be assessed on the mesial and distal surfaces of implants. Any changes between visits should be documen
Define Water of hydration and Bound Water - Water Found in Food? Water of hydration: This moisture is chemically bound to the constituents of the material and in most cases w
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!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd