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.
Explain Diagnostic Approach to Congenital Heart Disease ? It is often easy to recognise the presence of CHD in older children and adults. As in any other form of heart disease
Are sex-linked diseases associated only to genes of the X chromosome? There are so many X-linked diseases such like, hemophilia B, hemophilia A and adrenoleukodystrophy, but re
Stages of Wilm's tumour We shall now discuss about the various stages of Wilm's tumour. The extent of disease is staged according to the findings of surgery and the presen
How do the repairing enzymes of the genetic system act? There are enzymes inside the cells that detect errors or alterations in DNA molecules and begin a repair of those errors
Does pH affect the enzyme activity? The concentration of hydrogen ions in solution affects the enzyme activity. Every enzyme has maximal efficiency under an optimum pH. As p
Triacylglycerols, cholesterol and phospholipids are associatively insoluble in aqueous solution. Thus, they are transported around the body in the blood as parts of lipoproteins.
Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4
What are the kinds of plant geotropisms? Why do the root and the stem present opposite geotropisms? The kinds of geotropisms are the positive geotropism, that in which the plan
BIOLOGICAL PROPERTIES OF PROTOPLASM - 1 . Respiration - Oxidation of food to liberate energy is respiration. Every living beings respire but every living beings do no
What are likely to be (a) the coldest, (b) the warmest parts of the body? The extremities of the body (hands and fingers, feet and toes, ears and nose) are likely to be the col
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